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Question 1
Correct
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A patient is experiencing upper gastrointestinal bleeding after receiving heparin. You determine that protamine sulfate should be used to reverse the anticoagulation. How much protamine sulfate is needed to neutralize 200 IU of heparin?
Your Answer: 2 mg
Explanation:Protamine sulphate is a potent base that forms a stable salt complex with heparin, an acidic substance. This complex renders heparin inactive, making protamine sulphate a useful tool for neutralizing the effects of heparin. Additionally, protamine sulphate can be used to reverse the effects of LMWHs, although it is not as effective, providing only about two-thirds of the relative effect.
It is important to note that protamine sulphate also possesses its own weak intrinsic anticoagulant effect. This effect is believed to stem from its ability to inhibit the formation and activity of thromboplastin.
When administering protamine sulphate, it is typically done through slow intravenous injection. The dosage should be adjusted based on the amount of heparin that needs to be neutralized, the time that has passed since heparin administration, and the aPTT (activated partial thromboplastin time). As a general guideline, 1 mg of protamine can neutralize 100 IU of heparin. However, it is crucial to adhere to a maximum adult dose of 50 mg within a 10-minute period.
It is worth mentioning that protamine sulphate can have some adverse effects. It acts as a myocardial depressant, potentially leading to bradycardia (slow heart rate) and hypotension (low blood pressure). These effects may arise due to complement activation and leukotriene release.
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This question is part of the following fields:
- Haematology
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Question 2
Correct
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A 35-year-old man from Spain is found to have anemia. The results of his blood tests are as follows:
Hemoglobin (Hb): 9.3 g/dl (13-17 g/dl)
Mean Corpuscular Volume (MCV): 66 fl (80-100 fl)
Platelets: 219 x 109/l (150-400 x 109/l)
Serum Ferritin: 169 mg/l (15-200 mg/l)
Serum Iron: 200 mg/l (30-230 mg/l)
Hemoglobin A2 (HbA2): 6%
Blood Film: Presence of target cells
What is the MOST LIKELY diagnosis for this individual?Your Answer: Beta thalassaemia trait
Explanation:The beta thalassaemias are a group of blood disorders that occur when there is an abnormality in the production of the globin chains. These disorders are inherited in an autosomal recessive manner. In individuals with beta thalassaemia trait, there is a slight decrease in the production of beta-globin chains. This condition is most commonly found in people of Mediterranean and Asian descent.
The presentation of beta thalassaemia trait is characterized by a mild form of microcytic hypochromic anaemia. This type of anaemia can be challenging to differentiate from iron deficiency anaemia. However, it can be distinguished from iron deficiency anaemia by the presence of normal iron levels. Another useful marker for diagnosing beta thalassaemia trait is an elevated HbA2 level. A value greater than 3.5% is considered diagnostic for this condition.
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This question is part of the following fields:
- Haematology
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Question 3
Incorrect
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A 32-year-old woman with chronic anemia secondary to a diagnosis of sickle cell disease receives a blood transfusion. A few minutes after the blood transfusion has started, she experiences wheezing, chest discomfort, nausea, and widespread itching with a rash. Her blood pressure drops to 76/40 mmHg.
What is the most suitable course of treatment for this patient?Your Answer: Slow the transfusion rate and administer antihistamines
Correct Answer: Stop the transfusion and administer adrenaline
Explanation:Blood transfusion is a potentially life-saving treatment that can provide great clinical benefits. However, it also carries several risks and potential problems. These include immunological complications, administration errors, infections, immune dilution, and transfusion errors. While there have been improvements in safety procedures and efforts to minimize the use of transfusion, errors and serious adverse reactions still occur and often go unreported.
One rare complication of blood transfusion is transfusion-associated graft-vs-host disease (TA-GVHD). This condition typically presents with fever, rash, and diarrhea 1-4 weeks after the transfusion. Laboratory findings may show pancytopenia and abnormalities in liver function. Unlike GVHD after marrow transplantation, TA-GVHD leads to severe marrow aplasia with a mortality rate exceeding 90%. Unfortunately, there are currently no effective treatments available for this condition, and survival is rare, with death usually occurring within 1-3 weeks of the first symptoms.
During a blood transfusion, viable T lymphocytes from the donor are transfused into the recipient’s body. In TA-GVHD, these lymphocytes engraft and react against the recipient’s tissues. However, the recipient is unable to reject the donor lymphocytes due to factors such as immunodeficiency, severe immunosuppression, or shared HLA antigens. Supportive management is the only option for TA-GVHD.
The following summarizes the main complications and reactions that can occur during a blood transfusion:
Complication Features Management
Febrile transfusion reaction
– Presents with a 1-degree rise in temperature from baseline, along with chills and malaise.
– Most common reaction, occurring in 1 out of 8 transfusions.
– Usually caused by cytokines from leukocytes in transfused red cell or platelet components.
– Supportive management, with the use of paracetamol for symptom relief.Acute haemolytic reaction
– Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine.
– Often accompanied by a feeling of ‘impending doom’.
– Most serious type of reaction, often due to ABO incompatibility caused by administration errors.
– Immediate action required: stop the transfusion, administer IV fluids, and consider diuretics if necessary.Delayed haemolytic reaction
– Typically occurs 4-8 days after a blood transfusion.
– Symptoms include fever, anemia and/or hyperbilirubinemia -
This question is part of the following fields:
- Haematology
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Question 4
Incorrect
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A 45-year-old woman undergoes a blood transfusion for anemia caused by excessive vaginal bleeding. While receiving the second unit of blood, she experiences sensations of both heat and coldness. Her temperature is recorded at 38.1ºC, whereas her pre-transfusion temperature was 37ºC. Apart from this, she feels fine and does not exhibit any other symptoms.
What is the probable cause of this transfusion reaction?Your Answer: Bacterial contamination
Correct Answer: Cytokines from leukocytes
Explanation:Blood transfusion is a crucial medical treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion use, errors and adverse reactions still occur. One common adverse reaction is febrile transfusion reactions, which present as an unexpected rise in temperature during or after transfusion. This can be caused by cytokine accumulation or recipient antibodies reacting to donor antigens. Treatment for febrile transfusion reactions is supportive, and other potential causes should be ruled out.
Another serious complication is acute haemolytic reaction, which is often caused by ABO incompatibility due to administration errors. This reaction requires the transfusion to be stopped and IV fluids to be administered. Delayed haemolytic reactions can occur several days after a transfusion and may require monitoring and treatment for anaemia and renal function. Allergic reactions, TRALI (Transfusion Related Acute Lung Injury), TACO (Transfusion Associated Circulatory Overload), and GVHD (Graft-vs-Host Disease) are other potential complications that require specific management approaches.
In summary, blood transfusion carries risks and potential complications, but efforts have been made to improve safety procedures. It is important to be aware of these complications and to promptly address any adverse reactions that may occur during or after a transfusion.
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This question is part of the following fields:
- Haematology
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Question 5
Incorrect
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A 20 year old college student comes to the ER with a sore throat that has been bothering them for the past 10 days. After conducting a physical examination, you inform the patient that you suspect they may have glandular fever. You proceed to order blood tests.
Which of the following findings would support a diagnosis of glandular fever?Your Answer: Monocytosis
Correct Answer: Lymphocytosis
Explanation:In the blood tests, certain findings can support a diagnosis of glandular fever. One of these findings is lymphocytosis, which refers to an increased number of lymphocytes in the blood. Lymphocytes are a type of white blood cell that plays a crucial role in the immune response. In glandular fever, the Epstein-Barr virus (EBV) is the most common cause, and it primarily infects and activates lymphocytes, leading to their increased numbers in the blood.
On the other hand, neutropenia (a decreased number of neutrophils) and neutrophilia (an increased number of neutrophils) are not typically associated with glandular fever. Neutrophils are another type of white blood cell that helps fight off bacterial infections. In glandular fever, the primary involvement is with lymphocytes rather than neutrophils.
Monocytosis, which refers to an increased number of monocytes, can also be seen in glandular fever. Monocytes are another type of white blood cell that plays a role in the immune response. Their increased numbers can be a result of the immune system’s response to the Epstein-Barr virus.
Eosinophilia, an increased number of eosinophils, is not commonly associated with glandular fever. Eosinophils are white blood cells involved in allergic reactions and parasitic infections, and their elevation is more commonly seen in those conditions.
In summary, the presence of lymphocytosis and possibly monocytosis in the blood tests would support a diagnosis of glandular fever, while neutropenia, neutrophilia, and eosinophilia are less likely to be associated with this condition.
Further Reading:
Glandular fever, also known as infectious mononucleosis or mono, is a clinical syndrome characterized by symptoms such as sore throat, fever, and swollen lymph nodes. It is primarily caused by the Epstein-Barr virus (EBV), with other viruses and infections accounting for the remaining cases. Glandular fever is transmitted through infected saliva and primarily affects adolescents and young adults. The incubation period is 4-8 weeks.
The majority of EBV infections are asymptomatic, with over 95% of adults worldwide having evidence of prior infection. Clinical features of glandular fever include fever, sore throat, exudative tonsillitis, lymphadenopathy, and prodromal symptoms such as fatigue and headache. Splenomegaly (enlarged spleen) and hepatomegaly (enlarged liver) may also be present, and a non-pruritic macular rash can sometimes occur.
Glandular fever can lead to complications such as splenic rupture, which increases the risk of rupture in the spleen. Approximately 50% of splenic ruptures associated with glandular fever are spontaneous, while the other 50% follow trauma. Diagnosis of glandular fever involves various investigations, including viral serology for EBV, monospot test, and liver function tests. Additional serology tests may be conducted if EBV testing is negative.
Management of glandular fever involves supportive care and symptomatic relief with simple analgesia. Antiviral medication has not been shown to be beneficial. It is important to identify patients at risk of serious complications, such as airway obstruction, splenic rupture, and dehydration, and provide appropriate management. Patients can be advised to return to normal activities as soon as possible, avoiding heavy lifting and contact sports for the first month to reduce the risk of splenic rupture.
Rare but serious complications associated with glandular fever include hepatitis, upper airway obstruction, cardiac complications, renal complications, neurological complications, haematological complications, chronic fatigue, and an increased risk of lymphoproliferative cancers and multiple sclerosis.
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This question is part of the following fields:
- Haematology
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Question 6
Correct
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You review the blood results of a 65-year-old woman. Her full blood count is shown below:
Hb 11.9 g/dl (13-17 g/dl)
MCV 82 fl (80-100 fl)
WCC 18.4 x 109/l (4-11 x 109/l)
Neut 4.0 x 109/l (2.5-7.5 x 109/l)
Lymph 13.3 x 109/l (1.3-3.5 x 109/l)
Platelets 156 x 109/l (150-400 x 109/l)
What is the SINGLE most likely diagnosis?Your Answer: Chronic lymphocytic leukaemia
Explanation:Chronic lymphocytic leukaemia (CLL) is the most common type of leukaemia in adults. It occurs when mature lymphocytes multiply uncontrollably. About 95% of cases are of B-cell lineage.
CLL is typically a slow-growing form of leukaemia and is often discovered incidentally during routine blood tests. As the disease progresses, patients may experience swollen lymph nodes, enlarged liver and spleen, anemia, and increased susceptibility to infections.
This condition primarily affects adult men, with over 75% of CLL patients being men over the age of 50.
A blood test for CLL usually reveals an increased number of lymphocytes (typically more than 5 x 109/l, but it can be higher). Advanced stages of the disease may also show normochromic, normocytic anemia. A peripheral blood smear can confirm the presence of lymphocytosis, and smudge cells are often observed.
The Binet system is used to stage CLL, categorizing it as follows:
– Stage A: Hemoglobin (Hb) levels above 10 g/dl, platelet count above 100 x 109/l, involvement of fewer than 3 lymph node areas.
– Stage B: Hb levels above 10 g/dl, platelet count above 100 x 109/l, involvement of more than 3 lymph node areas.
– Stage C: Hb levels below 10 g/dl, platelet count below 100 x 109/l, or both.Early stages of CLL (Binet stage A and B without active disease) do not require immediate treatment and can be monitored through regular follow-up and blood tests. Patients with more advanced disease have various treatment options available, including monoclonal antibodies (such as rituximab), purine analogues (like fludarabine), and alkylating agents (such as chlorambucil).
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This question is part of the following fields:
- Haematology
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Question 7
Incorrect
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A 45-year-old patient with a history of exhaustion and weariness undergoes a complete blood count. The results reveal the presence of macrocytic anemia.
Which of the following is the LEAST probable underlying diagnosis?Your Answer: Hydroxyurea usage
Correct Answer: Thalassaemia
Explanation:Anaemia can be categorized based on the size of red blood cells. Microcytic anaemia, characterized by a mean corpuscular volume (MCV) of less than 80 fl, can be caused by various factors such as iron deficiency, thalassaemia, anaemia of chronic disease (which can also be normocytic), sideroblastic anaemia (which can also be normocytic), lead poisoning, and aluminium toxicity (although this is now rare and mainly affects haemodialysis patients).
On the other hand, normocytic anaemia, with an MCV ranging from 80 to 100 fl, can be attributed to conditions like haemolysis, acute haemorrhage, bone marrow failure, anaemia of chronic disease (which can also be microcytic), mixed iron and folate deficiency, pregnancy, chronic renal failure, and sickle-cell disease.
Lastly, macrocytic anaemia, characterized by an MCV greater than 100 fl, can be caused by factors such as B12 deficiency, folate deficiency, hypothyroidism, reticulocytosis, liver disease, alcohol abuse, myeloproliferative disease, myelodysplastic disease, and certain drugs like methotrexate, hydroxyurea, and azathioprine.
It is important to understand the different causes of anaemia based on red cell size as this knowledge can aid in the diagnosis and management of this condition.
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This question is part of the following fields:
- Haematology
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Question 8
Incorrect
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A 60-year-old woman has recently been diagnosed with Hodgkin’s lymphoma.
Which characteristic is considered to be a ‘B’ symptom of Hodgkin’s lymphoma?Your Answer: Pruritus
Correct Answer: Night sweats
Explanation:The ‘B’ symptoms associated with Hodgkin’s lymphoma include fever, night sweats, and weight loss. Fever is defined as a body temperature exceeding 38 degrees Celsius. Night sweats refer to excessive sweating during sleep. Weight loss is considered significant if it amounts to more than 10% of a person’s body weight over a period of six months. It is important to note that pain after consuming alcohol is a distinctive sign of Hodgkin’s lymphoma, but it is not classified as a ‘B’ symptom. This symptom is relatively rare, occurring in only 2-3% of individuals diagnosed with Hodgkin’s lymphoma.
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This question is part of the following fields:
- Haematology
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Question 9
Incorrect
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A 45-year-old man receives a blood transfusion for anemia secondary to excessive nosebleeds. While receiving the second unit, he complains of experiencing alternating sensations of heat and cold. His temperature is measured at 38.1ºC, compared to his pre-transfusion temperature of 37ºC. Apart from this, he feels fine and does not exhibit any other symptoms.
What is the most suitable course of treatment in this case?Your Answer: Stop the transfusion and administer diuretics
Correct Answer: Supportive measures and paracetamol
Explanation:Blood transfusion is a crucial medical treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion use, errors and adverse reactions still occur. One common adverse reaction is febrile transfusion reactions, which present as an unexpected rise in temperature during or after transfusion. This can be caused by cytokine accumulation or recipient antibodies reacting to donor antigens. Treatment for febrile transfusion reactions is supportive, and other potential causes should be ruled out.
Another serious complication is acute haemolytic reaction, which is often caused by ABO incompatibility due to administration errors. This reaction requires the transfusion to be stopped and IV fluids to be administered. Delayed haemolytic reactions can occur several days after a transfusion and may require monitoring and treatment for anaemia and renal function. Allergic reactions, TRALI (Transfusion Related Acute Lung Injury), TACO (Transfusion Associated Circulatory Overload), and GVHD (Graft-vs-Host Disease) are other potential complications that require specific management approaches.
In summary, blood transfusion carries risks and potential complications, but efforts have been made to improve safety procedures. It is important to be aware of these complications and to promptly address any adverse reactions that may occur during or after a transfusion.
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This question is part of the following fields:
- Haematology
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Question 10
Incorrect
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A 32-year-old woman with a history of sickle-cell disease undergoes a blood transfusion for severe anemia. Four weeks later, she arrives at the Emergency Department complaining of a skin rash, high temperature, and diarrhea. The medical team orders blood tests, which reveal low levels of all blood cells and abnormal liver function. What is the most probable transfusion reaction that occurred?
Your Answer: TRALI
Correct Answer: Graft-vs-host disease
Explanation:Blood transfusion is a potentially life-saving treatment that can provide great clinical benefits. However, it also carries several risks and potential problems. These include immunological complications, administration errors, infections, immune dilution, and transfusion errors. While there have been improvements in safety procedures and efforts to minimize the use of transfusion, errors and serious adverse reactions still occur and often go unreported.
One rare complication of blood transfusion is transfusion-associated graft-vs-host disease (TA-GVHD). This condition typically presents with fever, rash, and diarrhea 1-4 weeks after the transfusion. Laboratory findings may show pancytopenia and abnormalities in liver function. Unlike GVHD after marrow transplantation, TA-GVHD leads to severe marrow aplasia with a mortality rate exceeding 90%. Unfortunately, there are currently no effective treatments available for this condition, and survival is rare, with death usually occurring within 1-3 weeks of the first symptoms.
During a blood transfusion, viable T lymphocytes from the donor are transfused into the recipient’s body. In TA-GVHD, these lymphocytes engraft and react against the recipient’s tissues. However, the recipient is unable to reject the donor lymphocytes due to factors such as immunodeficiency, severe immunosuppression, or shared HLA antigens. Supportive management is the only option for TA-GVHD.
The following summarizes the main complications and reactions that can occur during a blood transfusion:
Complication Features Management
Febrile transfusion reaction
– Presents with a 1-degree rise in temperature from baseline, along with chills and malaise.
– Most common reaction, occurring in 1 out of 8 transfusions.
– Usually caused by cytokines from leukocytes in transfused red cell or platelet components.
– Supportive management, with the use of paracetamol for symptom relief.Acute haemolytic reaction
– Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine.
– Often accompanied by a feeling of ‘impending doom’.
– Most serious type of reaction, often due to ABO incompatibility caused by administration errors.
– Immediate action required: stop the transfusion, administer IV fluids, and consider diuretics if necessary.Delayed haemolytic reaction
– Typically occurs 4-8 days after a blood transfusion.
– Symptoms include fever, anemia and/or hyperbilirubinemia -
This question is part of the following fields:
- Haematology
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Question 11
Incorrect
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You assess a patient with sickle cell disease and a past medical history of multiple recurrent painful episodes. What is the approved treatment for reducing the frequency of painful crises in individuals with sickle cell disease?
Your Answer: Methotrexate
Correct Answer: Hydroxyurea
Explanation:The majority of treatments provided to individuals with sickle cell disease are supportive measures that have limited impact on the underlying pathophysiology of the condition.
Currently, the only approved therapy that can modify the disease is Hydroxyurea. This medication is believed to function by increasing the levels of fetal hemoglobin, which in turn decreases the concentration of HbS within the cells and reduces the abnormal hemoglobin tendency to form polymers.
Hydroxyurea is currently authorized for use in adult patients who experience recurrent moderate-to-severe painful crises (at least three in the past 12 months). Its approval is specifically for reducing the frequency of these painful episodes and the need for blood transfusions.
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This question is part of the following fields:
- Haematology
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Question 12
Incorrect
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A 42-year-old man with systemic lupus erythematosus (SLE) has been diagnosed with anaemia of chronic disease.
Which SINGLE statement regarding anaemia of chronic disease is true?Your Answer: There is usually a macrocytic anaemia
Correct Answer: Total iron binding capacity is usually reduced
Explanation:Anaemia of chronic disease is a type of anaemia that can occur in various chronic conditions, such as rheumatoid arthritis, systemic lupus erythematosus, tuberculosis, malignancy, malnutrition, hypothyroidism, hypopituitarism, chronic kidney disease, and chronic liver disease. The underlying mechanisms of this type of anaemia are complex and not fully understood, with multiple contributing factors involved. One important mediator in inflammatory diseases like rheumatoid arthritis is interleukin-6 (IL-6). Increased levels of IL-6 lead to the production of hepcidin, a hormone that regulates iron balance. Hepcidin prevents the release of iron from the reticulo-endothelial system and affects other aspects of iron metabolism.
Anaemia of chronic disease typically presents as a normochromic, normocytic anaemia, although it can also be microcytic. It is characterized by reduced serum iron, reduced transferrin saturation, and reduced total iron-binding capacity (TIBC). However, the serum ferritin levels are usually normal or increased. Distinguishing anaemia of chronic disease from iron-deficiency anaemia can be challenging, but in iron-deficiency anaemia, the TIBC is typically elevated, and serum ferritin is usually low.
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This question is part of the following fields:
- Haematology
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Question 13
Correct
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A 68-year-old woman presents with a 4-month history of easy bruising and fatigue. She has also experienced frequent nosebleeds over the past few weeks. She has had two respiratory infections and a urinary tract infection in the recent months and reports feeling unwell. You have arranged for her to undergo a series of blood tests, and the results of her complete blood count are as follows:
Hemoglobin (Hb): 7.4 g/dl (13-17 g/dl)
Mean Corpuscular Volume (MCV): 103 fl (80-100 fl)
Platelets: 46 x 109/l (150-400 x 109/l)
White Blood Cell Count (WCC): 4.4 x 109/l (4-11 x 109/l)
Neutrophils: 0.8 x 109/l (2.5-7.5 x 109/l)
Lymphocytes: 3.4 x 109/l (1.3-3.5 x 109/l)
Monocytes: 0.4 x 109/l (0.2-0.8 x 109/l)
Reticulocytes: 70 x 109/l (50-100 x 109/l)
What is the SINGLE most likely diagnosis?Your Answer: Myelodysplastic syndrome
Explanation:Myelodysplastic syndromes are a group of disorders affecting the haemopoietic stem cell, leading to ineffective production of myeloid blood cells. These conditions typically manifest between the ages of 60 and 75 and are more prevalent in men than women.
The clinical features of myelodysplastic syndromes include tiredness due to anaemia (the most common presentation), easy bruising, and a tendency to bleed. Laboratory findings often reveal anaemia (usually macrocytic or normocytic), neutropenia, thrombocytopenia, and abnormal cell morphology with oddly shaped macrocytes.
Chronic lymphocytic leukaemia (CLL) is the most common form of adult leukaemia, primarily affecting B-lymphocytes. It often presents asymptomatically in patients who undergo routine blood tests revealing elevated white cell counts and lymphocytosis. Men over the age of 50 account for over 75% of CLL cases. Blood films typically show a predominance of mature-looking lymphocytes and smear cells.
Iron deficiency anaemia is characterized by hypochromic microcytic anaemia and a reduced red blood cell count. Peripheral blood smears in iron deficiency anaemia may exhibit poikilocytosis (varying shapes) and anisocytosis (varying sizes). Pencil cells are also observed in this condition.
Vitamin B12 and folate deficiency can also cause macrocytic anaemia. However, the severity of anaemia and macrocytosis would generally need to be much more pronounced to result in neutropenia and thrombocytopenia. Therefore, a myelodysplastic syndrome is more likely in such cases.
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This question is part of the following fields:
- Haematology
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Question 14
Incorrect
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A 72-year-old woman with a history of atrial fibrillation presents with gastrointestinal bleeding. During the interview, you learn that she is currently on dabigatran etexilate.
What is the most appropriate option for reversing the effects of dabigatran etexilate?Your Answer: Protamine sulphate
Correct Answer: Idarucizumab
Explanation:Dabigatran etexilate is a medication that directly inhibits thrombin, a protein involved in blood clotting. It is prescribed to prevent venous thromboembolism in adults who have undergone total hip or knee replacement surgery. It is also approved for the treatment of deep-vein thrombosis and pulmonary embolism, as well as the prevention of recurrent episodes in adults.
The duration of treatment with dabigatran etexilate should be determined by considering the benefits of the medication against the risk of bleeding. For individuals with temporary risk factors such as recent surgery, trauma, or immobilization, a shorter duration of treatment (at least three months) may be appropriate. On the other hand, individuals with permanent risk factors or those with idiopathic deep-vein thrombosis or pulmonary embolism may require a longer duration of treatment.
Dabigatran etexilate is also indicated for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation who have additional risk factors such as previous stroke or transient ischemic attack, symptomatic heart failure, age 75 years or older, diabetes mellitus, or hypertension.
One of the advantages of dabigatran etexilate is its rapid onset of action. Additionally, routine monitoring of anticoagulant activity is not necessary as traditional tests like INR may not accurately reflect its effects. However, it is important to monitor patients for signs of bleeding or anemia, as hemorrhage is the most common side effect. If severe bleeding occurs, treatment with dabigatran etexilate should be discontinued.
There are certain situations in which dabigatran etexilate should not be used. These include active bleeding, a significant risk of major bleeding (such as recent gastrointestinal ulcer, oesophageal varices, recent brain, spine, or ophthalmic surgery, recent intracranial hemorrhage, malignant neoplasms, or vascular aneurysm), and as an anticoagulant for prosthetic heart valves.
In the UK, idarucizumab is the first approved agent that can reverse the anticoagulant effect of dabigatran etexilate.
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This question is part of the following fields:
- Haematology
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Question 15
Incorrect
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A 65 year old is brought to the emergency department due to confusion and mild fever. It is suspected that the patient has a urinary tract infection. The patient's family member informs you that the patient takes warfarin for atrial fibrillation but is unsure if they have taken it correctly due to confusion. An INR test is conducted and the result comes back as 8.2.
What would be the most suitable course of action?Your Answer: Give 25–50 u/kg four‐factor prothrombin complex concentrate
Correct Answer: Give vitamin K 1 mg by mouth
Explanation:When the INR (International Normalized Ratio) is above 8 but there is no sign of bleeding, the usual approach is to stop administering warfarin and instead provide oral vitamin K. If the INR is below 8 and there is no evidence of bleeding, it is appropriate to discontinue warfarin. However, if there is evidence of bleeding or the INR exceeds 8, reversal agents are administered. In cases where the INR is greater than 8 without any bleeding, oral vitamin K is typically prescribed at a dosage of 1-5 mg.
Further Reading:
Management of High INR with Warfarin
Major Bleeding:
– Stop warfarin immediately.
– Administer intravenous vitamin K 5 mg.
– Administer 25-50 u/kg four-factor prothrombin complex concentrate.
– If prothrombin complex concentrate is not available, consider using fresh frozen plasma (FFP).
– Seek medical attention promptly.INR > 8.0 with Minor Bleeding:
– Stop warfarin immediately.
– Administer intravenous vitamin K 1-3mg.
– Repeat vitamin K dose if INR remains high after 24 hours.
– Restart warfarin when INR is below 5.0.
– Seek medical advice if bleeding worsens or persists.INR > 8.0 without Bleeding:
– Stop warfarin immediately.
– Administer oral vitamin K 1-5 mg using the intravenous preparation orally.
– Repeat vitamin K dose if INR remains high after 24 hours.
– Restart warfarin when INR is below 5.0.
– Seek medical advice if any symptoms or concerns arise.INR 5.0-8.0 with Minor Bleeding:
– Stop warfarin immediately.
– Administer intravenous vitamin K 1-3mg.
– Restart warfarin when INR is below 5.0.
– Seek medical advice if bleeding worsens or persists.INR 5.0-8.0 without Bleeding:
– Withhold 1 or 2 doses of warfarin.
– Reduce subsequent maintenance dose.
– Monitor INR closely and seek medical advice if any concerns arise.Note: In cases of intracranial hemorrhage, prothrombin complex concentrate should be considered as it is faster acting than fresh frozen plasma (FFP).
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This question is part of the following fields:
- Haematology
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Question 16
Incorrect
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You are managing a hypoxic infant in the resuscitation bay. One of the possible diagnoses is methaemoglobinaemia. Can you explain the pathophysiology of methaemoglobinaemia?
Your Answer: Decreased CH3- groups associated with haem group
Correct Answer: Increased levels of haemoglobin which has been oxidised from Fe2+ to Fe3+
Explanation:Methaemoglobinaemia is a condition characterized by high levels of haemoglobin with iron in the ferric (Fe3+) state. This occurs when haemoglobin is oxidized from Fe2+ to Fe3+. Normally, NADH methaemoglobin reductase, also known as Cytochrome b5 reductase, regulates this process by transferring electrons from NADH to methaemoglobin, converting it back to haemoglobin. However, if there is a congenital or acquired dysfunction in the NADH methaemoglobin reductase enzyme system, it can lead to elevated levels of haemoglobin with iron in the Fe3+ state. Unfortunately, Fe3+ is unable to bind to haemoglobin.
Further Reading:
Methaemoglobinaemia is a condition where haemoglobin is oxidised from Fe2+ to Fe3+. This process is normally regulated by NADH methaemoglobin reductase, which transfers electrons from NADH to methaemoglobin, converting it back to haemoglobin. In healthy individuals, methaemoglobin levels are typically less than 1% of total haemoglobin. However, an increase in methaemoglobin can lead to tissue hypoxia as Fe3+ cannot bind oxygen effectively.
Methaemoglobinaemia can be congenital or acquired. Congenital causes include haemoglobin chain variants (HbM, HbH) and NADH methaemoglobin reductase deficiency. Acquired causes can be due to exposure to certain drugs or chemicals, such as sulphonamides, local anaesthetics (especially prilocaine), nitrates, chloroquine, dapsone, primaquine, and phenytoin. Aniline dyes are also known to cause methaemoglobinaemia.
Clinical features of methaemoglobinaemia include slate grey cyanosis (blue to grey skin coloration), chocolate blood or chocolate cyanosis (brown color of blood), dyspnoea, low SpO2 on pulse oximetry (which often does not improve with supplemental oxygen), and normal PaO2 on arterial blood gas (ABG) but low SaO2. Patients may tolerate hypoxia better than expected. Severe cases can present with acidosis, arrhythmias, seizures, and coma.
Diagnosis of methaemoglobinaemia is made by directly measuring the level of methaemoglobin using a co-oximeter, which is present in most modern blood gas analysers. Other investigations, such as a full blood count (FBC), electrocardiogram (ECG), chest X-ray (CXR), and beta-human chorionic gonadotropin (bHCG) levels (in pregnancy), may be done to assess the extent of the condition and rule out other contributing factors.
Active treatment is required if the methaemoglobin level is above 30% or if it is below 30% but the patient is symptomatic or shows evidence of tissue hypoxia. Treatment involves maintaining the airway and delivering high-flow oxygen, removing the causative agents, treating toxidromes and consider giving IV dextrose 5%.
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This question is part of the following fields:
- Haematology
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Question 17
Correct
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A 35-year-old patient with a history of exhaustion and weariness has a complete blood count scheduled. The complete blood count reveals that she has normocytic anemia.
What is the most probable underlying diagnosis?Your Answer: Haemolysis
Explanation:Anaemia can be categorized based on the size of red blood cells. Microcytic anaemia, characterized by a mean corpuscular volume (MCV) of less than 80 fl, can be caused by various factors such as iron deficiency, thalassaemia, anaemia of chronic disease (which can also be normocytic), sideroblastic anaemia (which can also be normocytic), lead poisoning, and aluminium toxicity (although this is now rare and mainly affects haemodialysis patients).
On the other hand, normocytic anaemia, with an MCV ranging from 80 to 100 fl, can be attributed to conditions like haemolysis, acute haemorrhage, bone marrow failure, anaemia of chronic disease (which can also be microcytic), mixed iron and folate deficiency, pregnancy, chronic renal failure, and sickle-cell disease.
Lastly, macrocytic anaemia, characterized by an MCV greater than 100 fl, can be caused by factors such as B12 deficiency, folate deficiency, hypothyroidism, reticulocytosis, liver disease, alcohol abuse, myeloproliferative disease, myelodysplastic disease, and certain drugs like methotrexate, hydroxyurea, and azathioprine.
It is important to understand the different causes of anaemia based on red cell size as this knowledge can aid in the diagnosis and management of this condition.
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This question is part of the following fields:
- Haematology
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Question 18
Correct
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A 50-year-old patient with a history of exhaustion and weariness has a complete blood count scheduled. The complete blood count reveals the presence of macrocytic anemia.
What is the most probable underlying diagnosis?Your Answer: Myeloproliferative disease
Explanation:Anaemia can be categorized based on the size of red blood cells. Microcytic anaemia, characterized by a mean corpuscular volume (MCV) of less than 80 fl, can be caused by various factors such as iron deficiency, thalassaemia, anaemia of chronic disease (which can also be normocytic), sideroblastic anaemia (which can also be normocytic), lead poisoning, and aluminium toxicity (although this is now rare and mainly affects haemodialysis patients).
On the other hand, normocytic anaemia, with an MCV ranging from 80 to 100 fl, can be attributed to conditions like haemolysis, acute haemorrhage, bone marrow failure, anaemia of chronic disease (which can also be microcytic), mixed iron and folate deficiency, pregnancy, chronic renal failure, and sickle-cell disease.
Lastly, macrocytic anaemia, characterized by an MCV greater than 100 fl, can be caused by factors such as B12 deficiency, folate deficiency, hypothyroidism, reticulocytosis, liver disease, alcohol abuse, myeloproliferative disease, myelodysplastic disease, and certain drugs like methotrexate, hydroxyurea, and azathioprine.
It is important to understand the different causes of anaemia based on red cell size as this knowledge can aid in the diagnosis and management of this condition.
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This question is part of the following fields:
- Haematology
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Question 19
Incorrect
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A 72 year old male visits the emergency department complaining of palpitations and difficulty breathing. An ECG confirms the patient is experiencing atrial fibrillation. Which scoring system is most appropriate for evaluating the patient's requirement for anticoagulation?
Your Answer: CHA2DS2-VASc
Correct Answer:
Explanation:The CHA2DS2-VASc score is a tool used to predict the likelihood of future stroke in individuals with atrial fibrillation (AF). It is scored on a scale of 0-9, with higher scores indicating a higher risk of stroke. If a male has a score of 1 or more, or if a female has a score of 2 or more, it is recommended to start anticoagulation therapy to prevent future strokes. However, it is important to assess the risk of bleeding before initiating anticoagulation using the HAS-BLED score. The HAS-BLED score does not evaluate the risk of stroke, but rather the risk of bleeding. QRISK3, on the other hand, is a tool used to estimate the risk of cardiovascular disease over a 10-year period and is primarily used to determine the benefits of starting lipid lowering drugs. It is the preferred tool recommended by NICE over the Framingham risk score.
Further Reading:
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting around 5% of patients over the age of 70-75 years and 10% of patients aged 80-85 years. While AF can cause palpitations and inefficient cardiac function, the most important aspect of managing patients with AF is reducing the increased risk of stroke.
AF can be classified as first detected episode, paroxysmal, persistent, or permanent. First detected episode refers to the initial occurrence of AF, regardless of symptoms or duration. Paroxysmal AF occurs when a patient has 2 or more self-terminating episodes lasting less than 7 days. Persistent AF refers to episodes lasting more than 7 days that do not self-terminate. Permanent AF is continuous atrial fibrillation that cannot be cardioverted or if attempts to do so are deemed inappropriate. The treatment goals for permanent AF are rate control and anticoagulation if appropriate.
Symptoms of AF include palpitations, dyspnea, and chest pain. The most common sign is an irregularly irregular pulse. An electrocardiogram (ECG) is essential for diagnosing AF, as other conditions can also cause an irregular pulse.
Managing patients with AF involves two key parts: rate/rhythm control and reducing stroke risk. Rate control involves slowing down the irregular pulse to avoid negative effects on cardiac function. This is typically achieved using beta-blockers or rate-limiting calcium channel blockers. If one drug is not effective, combination therapy may be used. Rhythm control aims to restore and maintain normal sinus rhythm through pharmacological or electrical cardioversion. However, the majority of patients are managed with a rate control strategy.
Reducing stroke risk in patients with AF is crucial. Risk stratifying tools, such as the CHA2DS2-VASc score, are used to determine the most appropriate anticoagulation strategy. Anticoagulation is recommended for patients with a score of 2 or more. Clinicians can choose between warfarin and novel oral anticoagulants (NOACs) for anticoagulation.
Before starting anticoagulation, the patient’s bleeding risk should be assessed using tools like the HAS-BLED score or the ORBIT tool. These tools evaluate factors such as hypertension, abnormal renal or liver function, history of bleeding, age, and use of drugs that predispose to bleeding.
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This question is part of the following fields:
- Haematology
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Question 20
Incorrect
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A 68-year-old woman with a history of chronic anemia receives a blood transfusion as part of her treatment protocol. She has a known history of heart failure, for which she takes metoprolol and hydrochlorothiazide. She becomes short of breath, volume overloaded, and edematous during the transfusion.
Which of the following tests will be most useful in confirming the diagnosis?Your Answer: Coombs test
Correct Answer: BNP
Explanation:Transfusion-associated circulatory overload (TACO) is a reaction that occurs when a large volume of blood is infused rapidly. It is the second leading cause of deaths related to transfusions, accounting for about 20% of all fatalities.
TACO typically happens in patients with limited cardiac reserve or chronic anemia who receive a fast blood transfusion. Elderly individuals, infants, and severely anemic patients are particularly vulnerable.
The common signs of TACO include acute respiratory distress, rapid heartbeat, high blood pressure, the appearance of acute or worsening fluid accumulation in the lungs on a chest X-ray, and evidence of excessive fluid retention.
The B-type natriuretic peptide (BNP) can be a helpful diagnostic tool for TACO. Usually, the BNP level is elevated to at least 1.5 times the baseline before the transfusion.
In many cases, simply slowing down the rate of transfusion, positioning the patient upright, and administering diuretics will be sufficient. In more severe cases, the transfusion should be stopped, and non-invasive ventilation may be considered.
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This question is part of the following fields:
- Haematology
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Question 21
Incorrect
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A 45-year-old man presents with fatigue, unintentional weight loss, and a tongue that appears beefy red.
His blood test results are as follows:
Hemoglobin (Hb): 7.4 g/dl (normal range: 11.5-15.5 g/dl)
Mean Corpuscular Volume (MCV): 115 fl (normal range: 80-100 fl)
Platelets: 73 x 109/l (normal range: 150-400 x 109/l)
Intrinsic factor antibodies: positive
Blood film: shows anisocytosis
What is the SINGLE most likely diagnosis?Your Answer: Myelodysplastic syndrome
Correct Answer: Vitamin B12 deficiency
Explanation:Pernicious anaemia is a condition that affects the stomach and is characterized by the loss of gastric parietal cells and impaired secretion of intrinsic factor (IF). IF is crucial for the absorption of vitamin B12 in the ileum, and as a result, megaloblastic anaemia occurs. This condition is commonly seen in individuals who have undergone gastrectomy.
The clinical manifestations of pernicious anaemia include weight loss, loss of appetite, fatigue, diarrhoea, and a distinct lemon-yellow skin color, which is caused by a combination of haemolytic jaundice and the paleness associated with anaemia. Other symptoms may include glossitis (inflammation of the tongue) and oral ulceration. Neurological symptoms can also occur, such as subacute combined degeneration of the spinal cord and peripheral neuropathy. The earliest sign of central nervous system involvement is often the loss of position and vibratory sense in the extremities.
When investigating pernicious anaemia, certain findings may be observed. These include macrocytic anaemia, neutropaenia, thrombocytopaenia, anisocytosis and poikilocytosis on a blood film, low serum B12 levels, elevated serum bilirubin levels (indicating haemolysis), the presence of intrinsic factor antibodies, and a positive Schilling test.
The treatment for pernicious anaemia involves lifelong supplementation of vitamin B12, typically administered through intramuscular injections.
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This question is part of the following fields:
- Haematology
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Question 22
Correct
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A 35-year-old man receives a blood transfusion. Shortly after the transfusion is started, he experiences chills and shivering. His vital signs are as follows: heart rate of 116 beats per minute, blood pressure of 80/48, temperature of 40°C, and oxygen saturation of 97% on room air.
Which of the following transfusion reactions is most likely to have happened?Your Answer: Bacterial contamination
Explanation:Transfusion transmitted bacterial infection is a rare complication that can occur during blood transfusion. It is more commonly associated with platelet transfusion, as platelets are stored at room temperature. Additionally, previously frozen components that are thawed using a water bath and red cell components stored for several weeks are also at a higher risk for bacterial infection.
Both Gram-positive and Gram-negative bacteria have been implicated in transfusion-transmitted bacterial infection, but Gram-negative bacteria are known to cause more severe illness and have higher rates of morbidity and mortality. Among the bacterial organisms, Yersinia enterocolitica is the most commonly associated with this type of infection. This particular organism is able to multiply at low temperatures and utilizes iron as a nutrient, making it well-suited for proliferation in blood stores.
The clinical features of transfusion-transmitted bacterial infection typically manifest shortly after the transfusion begins. These features include a high fever, chills and rigors, nausea and vomiting, tachycardia, hypotension, and even circulatory collapse.
If there is suspicion of a transfusion-transmitted bacterial infection, it is crucial to immediately stop the transfusion. Blood cultures and a Gram-stain should be requested to identify the specific bacteria causing the infection. Broad-spectrum antibiotics should be initiated promptly. Furthermore, the blood pack should be returned to the blood bank urgently for culture and Gram-stain analysis.
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This question is part of the following fields:
- Haematology
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Question 23
Incorrect
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A 68-year-old man with a history of atrial fibrillation (AF) presents a small, surface-level, cut on his leg that is oozing and still bleeding despite applying pressure for approximately 30 minutes. He is currently taking warfarin for his AF and his INR today is 8.6.
What is the most suitable approach to manage the reversal of his warfarin?Your Answer: Stop warfarin and give IV vitamin K and prothrombin complex concentrate
Correct Answer: Stop warfarin and give IV vitamin K
Explanation:The current recommendations from NICE for managing warfarin in the presence of bleeding or an abnormal INR are as follows:
In cases of major active bleeding, regardless of the INR level, the first step is to stop administering warfarin. Next, 5 mg of vitamin K (phytomenadione) should be given intravenously. Additionally, dried prothrombin complex concentrate, which contains factors II, VII, IX, and X, should be administered. If dried prothrombin complex is not available, fresh frozen plasma can be given at a dose of 15 ml/kg.
If the INR is greater than 8.0 and there is minor bleeding, warfarin should be stopped. Slow injection of 1-3 mg of vitamin K can be given, and this dose can be repeated after 24 hours if the INR remains high. Warfarin can be restarted once the INR is less than 5.0.
If the INR is greater than 8.0 with no bleeding, warfarin should be stopped. Oral administration of 1-5 mg of vitamin K can be given, and this dose can be repeated after 24 hours if the INR remains high. Warfarin can be restarted once the INR is less than 5.0.
If the INR is between 5.0-8.0 with minor bleeding, warfarin should be stopped. Slow injection of 1-3 mg of vitamin K can be given, and warfarin can be restarted once the INR is less than 5.0.
If the INR is between 5.0-8.0 with no bleeding, one or two doses of warfarin should be withheld, and the subsequent maintenance dose should be reduced.
For more information, please refer to the NICE Clinical Knowledge Summary on the management of warfarin therapy and the BNF guidance on the use of phytomenadione.
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This question is part of the following fields:
- Haematology
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Question 24
Incorrect
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A 65-year-old patient presents with sudden-onset spontaneous epistaxis. You are struggling to control the bleeding and decide to insert bilateral ‘Rapid Rhino’ nasal packs. The patient informs you that he has von Willebrand disease.
What is dysfunctional in von Willebrand disease?Your Answer: Tissue thromboplastin release
Correct Answer: Platelet adhesion
Explanation:Von Willebrand disease (vWD) is a common hereditary coagulation disorder that affects about 1 in 100 people. It occurs due to a deficiency in Von Willebrand factor (vWF), which is responsible for protecting factor VIII from breaking down too quickly in the blood. Additionally, vWF is necessary for proper platelet adhesion, so a lack of it can lead to abnormal platelet function. As a result, both the APTT and bleeding time are prolonged, while the platelet count and thrombin time remain unaffected.
In many cases, vWD goes unnoticed as patients do not experience any symptoms. It is often diagnosed incidentally during a routine clotting profile check. However, if symptoms do occur, the most common ones are easy bruising, nosebleeds, and heavy menstrual bleeding. In severe cases, more serious bleeding and joint bleeds can occur.
For mild cases of von Willebrand disease, bleeding can be treated with desmopressin. This medication helps increase the patient’s own levels of vWF by releasing stored vWF from the Weibel-Palade bodies in the endothelial cells. These bodies are storage granules found in the inner lining of blood vessels and the heart. In more severe cases, replacement therapy is necessary, which involves infusing cryoprecipitate or Factor VIII concentrate. Replacement therapy is recommended for patients with severe von Willebrand’s disease who are undergoing moderate or major surgical procedures.
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This question is part of the following fields:
- Haematology
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Question 25
Incorrect
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A 40-year-old man has a confirmed diagnosis of von Willebrand disease.
Which of the following abnormalities is MOST likely to appear on his clotting profile?Your Answer: Reduced APTT
Correct Answer: Prolonged APTT
Explanation:Von Willebrand disease (vWD) is a common hereditary coagulation disorder that affects approximately 1 in 100 individuals. It occurs due to a deficiency in Von Willebrand factor (vWF), which plays a crucial role in blood clotting. vWF not only binds to factor VIII to protect it from rapid breakdown, but it is also necessary for proper platelet adhesion. When vWF is lacking, both factor VIII levels and platelet function are affected, leading to prolonged APTT and bleeding time. However, the platelet count and thrombin time remain unaffected.
While some individuals with vWD may not experience any symptoms and are diagnosed incidentally during a clotting profile check, others may present with easy bruising, nosebleeds (epistaxis), and heavy menstrual bleeding (menorrhagia). In severe cases, more significant bleeding and joint bleeding (haemarthrosis) can occur.
For mild cases of von Willebrand disease, bleeding can be managed with desmopressin. This medication works by stimulating the release of vWF stored in the Weibel-Palade bodies, which are storage granules found in the endothelial cells lining the blood vessels and heart. By increasing the patient’s own levels of vWF, desmopressin helps improve clotting. In more severe cases, replacement therapy is necessary. This involves infusing cryoprecipitate or Factor VIII concentrate to provide the missing vWF. Replacement therapy is particularly recommended for patients with severe von Willebrand’s disease who are undergoing moderate or major surgical procedures.
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This question is part of the following fields:
- Haematology
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Question 26
Incorrect
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A 45-year-old patient presents with frequent bruising and recurrent nosebleeds. She informs you that she has a rare platelet disorder and provides you with her outpatient letter from the hematology department, which includes details about the condition. According to the letter, her disorder is attributed to decreased levels of glycoprotein IIb/IIIa.
What is the MOST LIKELY diagnosis for this patient?Your Answer: Von Willebrand disease
Correct Answer: Glanzmann’s thrombasthenia
Explanation:Glanzmann’s thrombasthenia is an uncommon condition affecting platelets, where they have a deficiency or abnormality in glycoprotein IIb/IIIa. This disorder leads to platelet dysfunction and can result in various complications.
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This question is part of the following fields:
- Haematology
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Question 27
Incorrect
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A 62-year-old man with a history of rheumatoid arthritis presents with fatigue. His arthritis is well managed with sulfasalazine. His blood test results are as follows:
Hemoglobin (Hb): 9.8 g/dl (11.5-15.5 g/dl)
Mean Corpuscular Volume (MCV): 80 fl (75-87 fl)
Platelets: 176 x 109/l (150-400 x 109/l)
Serum Iron: 5 mmol/l (10-28 mmol/l)
Total Iron-Binding Capacity (TIBC): 35 mmol/l (45-72 mmol/l)
What is the most likely diagnosis for this patient?Your Answer: Iron-deficiency anaemia
Correct Answer: Anaemia of chronic disease
Explanation:Anaemia of chronic disease is a type of anaemia that can occur in various chronic conditions, such as rheumatoid arthritis, systemic lupus erythematosus, tuberculosis, malignancy, malnutrition, hypothyroidism, hypopituitarism, chronic kidney disease, and chronic liver disease. The underlying mechanisms of this type of anaemia are complex and not fully understood, with multiple contributing factors involved. One important mediator in inflammatory diseases like rheumatoid arthritis is interleukin-6 (IL-6). Increased levels of IL-6 lead to the production of hepcidin, a hormone that regulates iron balance. Hepcidin prevents the release of iron from the reticulo-endothelial system and affects other aspects of iron metabolism.
Anaemia of chronic disease typically presents as a normochromic, normocytic anaemia, although it can also be microcytic. It is characterized by reduced serum iron, reduced transferrin saturation, and reduced total iron-binding capacity (TIBC). However, the serum ferritin levels are usually normal or increased. Distinguishing anaemia of chronic disease from iron-deficiency anaemia can be challenging, but in iron-deficiency anaemia, the TIBC is typically elevated, and serum ferritin is usually low.
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This question is part of the following fields:
- Haematology
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Question 28
Incorrect
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A 32-year-old man receives a blood transfusion and experiences a severe transfusion reaction. His condition quickly worsens, and he ultimately succumbs to this reaction. His death is reported to Serious Hazards of Transfusion (SHOT).
What is the primary cause of transfusion-related fatalities in the United Kingdom?Your Answer: TACO
Correct Answer: TRALI
Explanation:Transfusion-related lung injury (TRALI) is responsible for about one-third of all transfusion-related deaths, making it the leading cause. On the other hand, transfusion-associated circulatory overload (TACO) accounts for approximately 20% of these fatalities, making it the second leading cause. TACO occurs when a large volume of blood is rapidly infused, particularly in patients with limited cardiac reserve or chronic anemia. Elderly individuals, infants, and severely anemic patients are especially vulnerable to this reaction.
The typical signs of TACO include acute respiratory distress, rapid heart rate, high blood pressure, the appearance of acute or worsening pulmonary edema on a chest X-ray, and evidence of excessive fluid accumulation. In many cases, simply reducing the transfusion rate, positioning the patient upright, and administering diuretics will be sufficient to manage the condition. However, in more severe cases, it is necessary to halt the transfusion and consider non-invasive ventilation.
Transfusion-related acute lung injury (TRALI) is defined as new acute lung injury (ALI) that occurs during or within six hours of transfusion, not explained by another ALI risk factor. Transfusion of part of one unit of any blood product can cause TRALI.
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This question is part of the following fields:
- Haematology
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Question 29
Incorrect
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A 35-year-old woman with a history of sickle cell disease undergoes a blood transfusion. After one week, she experiences a slight fever and notices dark urine. Blood tests are ordered, revealing elevated bilirubin and LDH levels, as well as a positive Direct Antiglobulin Test (DAT).
Which of the following transfusion reactions is the most probable cause of these symptoms?Your Answer: TACO
Correct Answer: Delayed haemolytic reaction
Explanation:Blood transfusion is a crucial treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion use, errors and adverse reactions still occur.
Delayed haemolytic transfusion reactions (DHTRs) typically occur 4-8 days after a blood transfusion, but can sometimes manifest up to a month later. The symptoms are similar to acute haemolytic transfusion reactions but are usually less severe. Patients may experience fever, inadequate rise in haemoglobin, jaundice, reticulocytosis, positive antibody screen, and positive Direct Antiglobulin Test (Coombs test). DHTRs are more common in patients with sickle cell disease who have received frequent transfusions.
These reactions are caused by the presence of a low titre antibody that is too weak to be detected during cross-match and unable to cause lysis at the time of transfusion. The severity of DHTRs depends on the immunogenicity or dose of the antigen. Blood group antibodies associated with DHTRs include those of the Kidd, Duffy, Kell, and MNS systems. Most DHTRs have a benign course and do not require treatment. However, severe haemolysis with anaemia and renal failure can occur, so monitoring of haemoglobin levels and renal function is necessary. If an antibody is detected, antigen-negative blood can be requested for future transfusions.
Here is a summary of the main transfusion reactions and complications:
1. Febrile transfusion reaction: Presents with a 1-degree rise in temperature from baseline, along with chills and malaise. It is the most common reaction and is usually caused by cytokines from leukocytes in transfused red cell or platelet components. Supportive treatment with paracetamol is helpful.
2. Acute haemolytic reaction: Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine. It is the most serious type of reaction and often occurs due to ABO incompatibility from administration errors. The transfusion should be stopped, and IV fluids should be administered. Diuretics may be required.
3. Delayed haemolytic reaction: This reaction typically occurs 4-8 days after a blood transfusion and presents with fever, anaemia, jaundice and haemoglobuinuria. Direct antiglobulin (Coombs) test positive. Due to low titre antibody too weak to detect in cross-match and unable to cause lysis at time of transfusion. Most delayed haemolytic reactions have a benign course and require no treatment. Monitor anaemia and renal function and treat as required.
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This question is part of the following fields:
- Haematology
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Question 30
Correct
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A 32-year-old woman with a history of sickle-cell disease undergoes a blood transfusion for severe anemia. Four weeks later, she arrives at the Emergency Department complaining of a skin rash, high body temperature, and diarrhea. Laboratory tests are ordered, revealing low levels of all blood cells and abnormal liver function.
What is the probable cause of this transfusion reaction?Your Answer: T lymphocytes reacting against recipient’s tissues
Explanation:Blood transfusion is a potentially life-saving treatment that can provide great clinical benefits. However, it also carries several risks and potential problems. These include immunological complications, administration errors, infections, immune dilution, and transfusion errors. While there have been improvements in safety procedures and efforts to minimize the use of transfusion, errors and serious adverse reactions still occur and often go unreported.
One rare complication of blood transfusion is transfusion-associated graft-vs-host disease (TA-GVHD). This condition typically presents with fever, rash, and diarrhea 1-4 weeks after the transfusion. Laboratory findings may show pancytopenia and abnormalities in liver function. Unlike GVHD after marrow transplantation, TA-GVHD leads to severe marrow aplasia with a mortality rate exceeding 90%. Unfortunately, there are currently no effective treatments available for this condition, and survival is rare, with death usually occurring within 1-3 weeks of the first symptoms.
During a blood transfusion, viable T lymphocytes from the donor are transfused into the recipient’s body. In TA-GVHD, these lymphocytes engraft and react against the recipient’s tissues. However, the recipient is unable to reject the donor lymphocytes due to factors such as immunodeficiency, severe immunosuppression, or shared HLA antigens. Supportive management is the only option for TA-GVHD.
The following summarizes the main complications and reactions that can occur during a blood transfusion:
Complication Features Management
Febrile transfusion reaction
– Presents with a 1-degree rise in temperature from baseline, along with chills and malaise.
– Most common reaction, occurring in 1 out of 8 transfusions.
– Usually caused by cytokines from leukocytes in transfused red cell or platelet components.
– Supportive management, with the use of paracetamol for symptom relief.Acute haemolytic reaction
– Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine.
– Often accompanied by a feeling of ‘impending doom’.
– Most serious type of reaction, often due to ABO incompatibility caused by administration errors.
– Immediate action required: stop the transfusion, administer IV fluids, and consider diuretics if necessary.Delayed haemolytic reaction
– Typically occurs 4-8 days after a blood transfusion.
– Symptoms include fever, anemia and/or hyperbilirubinemia -
This question is part of the following fields:
- Haematology
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Question 31
Incorrect
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A 68-year-old man with a history of atrial fibrillation (AF) is found to have an INR of 7.3 during a routine check. He is feeling fine and does not have any signs of bleeding.
What is the most suitable approach to reverse the effects of warfarin in this patient?Your Answer: Stop warfarin for 5 days and re-check INR
Correct Answer: Withhold 1-2 doses of warfarin and reduce subsequent maintenance dose
Explanation:The current recommendations from NICE for managing warfarin in the presence of bleeding or an abnormal INR are as follows:
In cases of major active bleeding, regardless of the INR level, the first step is to stop administering warfarin. Next, 5 mg of vitamin K (phytomenadione) should be given intravenously. Additionally, dried prothrombin complex concentrate, which contains factors II, VII, IX, and X, should be administered. If dried prothrombin complex is not available, fresh frozen plasma can be given at a dose of 15 ml/kg.
If the INR is greater than 8.0 and there is minor bleeding, warfarin should be stopped. Slow injection of 1-3 mg of vitamin K can be given, and this dose can be repeated after 24 hours if the INR remains high. Warfarin can be restarted once the INR is less than 5.0.
If the INR is greater than 8.0 with no bleeding, warfarin should be stopped. Oral administration of 1-5 mg of vitamin K can be given, and this dose can be repeated after 24 hours if the INR remains high. Warfarin can be restarted once the INR is less than 5.0.
If the INR is between 5.0-8.0 with minor bleeding, warfarin should be stopped. Slow injection of 1-3 mg of vitamin K can be given, and warfarin can be restarted once the INR is less than 5.0.
If the INR is between 5.0-8.0 with no bleeding, one or two doses of warfarin should be withheld, and the subsequent maintenance dose should be reduced.
For more information, please refer to the NICE Clinical Knowledge Summary on the management of warfarin therapy and the BNF guidance on the use of phytomenadione.
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This question is part of the following fields:
- Haematology
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Question 32
Correct
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A 68-year-old man with a history of atrial fibrillation (AF) presents with a head injury and decreased level of consciousness. He is currently taking warfarin for his AF, and his INR was 2.5 a few days ago. A CT scan of his head reveals the presence of a subdural hematoma.
What is the most suitable approach to manage the reversal of warfarin in this patient?Your Answer: Stop warfarin and give IV vitamin K and prothrombin complex concentrate
Explanation:The current recommendations from NICE for managing warfarin in the presence of bleeding or an abnormal INR are as follows:
In cases of major active bleeding, regardless of the INR level, the first step is to stop administering warfarin. Next, 5 mg of vitamin K (phytomenadione) should be given intravenously. Additionally, dried prothrombin complex concentrate, which contains factors II, VII, IX, and X, should be administered. If dried prothrombin complex is not available, fresh frozen plasma can be given at a dose of 15 ml/kg.
If the INR is greater than 8.0 and there is minor bleeding, warfarin should be stopped. Slow injection of 1-3 mg of vitamin K can be given, and this dose can be repeated after 24 hours if the INR remains high. Warfarin can be restarted once the INR is less than 5.0.
If the INR is greater than 8.0 with no bleeding, warfarin should be stopped. Oral administration of 1-5 mg of vitamin K can be given, and this dose can be repeated after 24 hours if the INR remains high. Warfarin can be restarted once the INR is less than 5.0.
If the INR is between 5.0-8.0 with minor bleeding, warfarin should be stopped. Slow injection of 1-3 mg of vitamin K can be given, and warfarin can be restarted once the INR is less than 5.0.
If the INR is between 5.0-8.0 with no bleeding, one or two doses of warfarin should be withheld, and the subsequent maintenance dose should be reduced.
For more information, please refer to the NICE Clinical Knowledge Summary on the management of warfarin therapy and the BNF guidance on the use of phytomenadione.
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This question is part of the following fields:
- Haematology
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Question 33
Incorrect
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A 68-year-old woman with a history of chronic anemia receives a blood transfusion as part of her treatment plan. She has a known history of heart failure, for which she takes metoprolol and hydrochlorothiazide. Her most recent BNP was measured at 130 pmol/l. Six hours after the start of the transfusion, she experiences shortness of breath and her pre-existing swelling in the legs worsens. Her blood pressure increases to 175/110 mmHg and her BNP is measured again and is now 200 pmol/l.
Which of the following transfusion reactions is most likely to have occurred?Your Answer: Acute haemolytic reaction
Correct Answer: TACO
Explanation:Blood transfusion is a potentially life-saving treatment that can provide great clinical benefits. However, it also carries several risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there has been an increased awareness of these risks and improved reporting systems, transfusion errors and serious adverse reactions still occur and may go unreported.
One specific transfusion reaction is transfusion-associated circulatory overload (TACO), which occurs when a large volume of blood is rapidly infused. It is the second leading cause of transfusion-related deaths, accounting for about 20% of fatalities. TACO is more likely to occur in patients with diminished cardiac reserve or chronic anemia, particularly in the elderly, infants, and severely anemic patients.
The typical clinical features of TACO include acute respiratory distress, tachycardia, hypertension, acute or worsening pulmonary edema on chest X-ray, and evidence of positive fluid balance. The B-type natriuretic peptide (BNP) can be a useful diagnostic tool for TACO, with levels usually elevated to at least 1.5 times the pre-transfusion baseline.
In many cases, simply slowing the transfusion rate, placing the patient in an upright position, and administering diuretics can be sufficient for managing TACO. In more severe cases, the transfusion should be stopped, and non-invasive ventilation may be considered.
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This question is part of the following fields:
- Haematology
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Question 34
Incorrect
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A 65 year old patient arrives at the emergency department complaining of a productive cough and fever. The patient's primary care physician had prescribed antibiotics a few days ago to treat a suspected respiratory infection. The patient's INR is tested as they are on warfarin for atrial fibrillation. The INR comes back as 6.7. How should you approach managing this patient's elevated INR?
Your Answer: Give 5 mg intravenous vitamin K
Correct Answer: Withhold 1-2 doses of warfarin and recheck INR
Explanation:If a patient’s INR reading is above 5, it is necessary to take action. In this case, the patient’s INR is between 5 and 8, but there is no evidence of bleeding. According to the provided table, it is recommended to temporarily stop 1-2 doses of warfarin and closely monitor the INR. While it may be optional to switch antibiotics, it is not a crucial step in this situation.
Further Reading:
Management of High INR with Warfarin
Major Bleeding:
– Stop warfarin immediately.
– Administer intravenous vitamin K 5 mg.
– Administer 25-50 u/kg four-factor prothrombin complex concentrate.
– If prothrombin complex concentrate is not available, consider using fresh frozen plasma (FFP).
– Seek medical attention promptly.INR > 8.0 with Minor Bleeding:
– Stop warfarin immediately.
– Administer intravenous vitamin K 1-3mg.
– Repeat vitamin K dose if INR remains high after 24 hours.
– Restart warfarin when INR is below 5.0.
– Seek medical advice if bleeding worsens or persists.INR > 8.0 without Bleeding:
– Stop warfarin immediately.
– Administer oral vitamin K 1-5 mg using the intravenous preparation orally.
– Repeat vitamin K dose if INR remains high after 24 hours.
– Restart warfarin when INR is below 5.0.
– Seek medical advice if any symptoms or concerns arise.INR 5.0-8.0 with Minor Bleeding:
– Stop warfarin immediately.
– Administer intravenous vitamin K 1-3mg.
– Restart warfarin when INR is below 5.0.
– Seek medical advice if bleeding worsens or persists.INR 5.0-8.0 without Bleeding:
– Withhold 1 or 2 doses of warfarin.
– Reduce subsequent maintenance dose.
– Monitor INR closely and seek medical advice if any concerns arise.Note: In cases of intracranial hemorrhage, prothrombin complex concentrate should be considered as it is faster acting than fresh frozen plasma (FFP).
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This question is part of the following fields:
- Haematology
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Question 35
Incorrect
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A 55-year-old man receives a blood transfusion. Shortly after the transfusion is started, he experiences chills and shivering. His vital signs are as follows: heart rate of 116 beats per minute, blood pressure of 80/48, temperature of 40°C, and oxygen saturation of 97% on room air.
What is the most suitable course of action for treatment?Your Answer: Supportive measures and paracetamol
Correct Answer: Stop the transfusion and administer antibiotics
Explanation:Transfusion transmitted bacterial infection is a rare complication that can occur during blood transfusion. It is more commonly associated with platelet transfusion, as platelets are stored at room temperature. Additionally, previously frozen components that are thawed using a water bath and red cell components stored for several weeks are also at a higher risk for bacterial infection.
Both Gram-positive and Gram-negative bacteria have been implicated in transfusion-transmitted bacterial infection, but Gram-negative bacteria are known to cause more severe illness and have higher rates of morbidity and mortality. Among the bacterial organisms, Yersinia enterocolitica is the most commonly associated with this type of infection. This particular organism is able to multiply at low temperatures and utilizes iron as a nutrient, making it well-suited for proliferation in blood stores.
The clinical features of transfusion-transmitted bacterial infection typically manifest shortly after the transfusion begins. These features include a high fever, chills and rigors, nausea and vomiting, tachycardia, hypotension, and even circulatory collapse.
If there is suspicion of a transfusion-transmitted bacterial infection, it is crucial to immediately stop the transfusion. Blood cultures and a Gram-stain should be requested to identify the specific bacteria causing the infection. Broad-spectrum antibiotics should be initiated promptly. Furthermore, the blood pack should be returned to the blood bank urgently for culture and Gram-stain analysis.
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This question is part of the following fields:
- Haematology
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Question 36
Incorrect
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A 60-year-old man receives a blood transfusion due to ongoing rectal bleeding and a hemoglobin level of 6 mg/dL. Shortly after starting the transfusion, he experiences discomfort and a burning sensation at the site of his IV, along with complaints of nausea, intense lower back pain, and a sense of impending catastrophe. His temperature is measured and found to be 39.2°C.
Which of the following transfusion reactions is most probable in this case?Your Answer: Febrile transfusion reaction
Correct Answer: Acute haemolytic reaction
Explanation:Blood transfusion is a crucial medical treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion usage, errors and adverse reactions still occur.
One serious complication is acute haemolytic transfusion reactions, which happen when incompatible red cells are transfused and react with the patient’s own antibodies. This usually occurs due to human error, such as mislabelling sample tubes or request forms. Symptoms of this reaction include a feeling of impending doom, fever, chills, pain and warmth at the transfusion site, nausea, vomiting, and back, joint, and chest pain. Immediate action should be taken to stop the transfusion, replace the donor blood with normal saline or another suitable crystalloid, and check the blood to confirm the intended recipient. IV diuretics may be administered to increase renal blood flow, and urine output should be maintained.
Another common complication is febrile transfusion reaction, which presents with a 1-degree rise in temperature from baseline, along with chills and malaise. This reaction is usually caused by cytokines from leukocytes in the transfused blood components. Supportive treatment is typically sufficient, and paracetamol can be helpful.
Allergic reactions can also occur, usually due to foreign plasma proteins or anti-IgA. These reactions often present with urticaria, pruritus, and hives, and in severe cases, laryngeal edema or bronchospasm may occur. Symptomatic treatment with antihistamines is usually enough, and there is usually no need to stop the transfusion. However, if anaphylaxis occurs, the transfusion should be stopped, and the patient should be administered adrenaline and treated according to the ALS protocol.
Transfusion-related acute lung injury (TRALI) is a severe complication characterized by non-cardiogenic pulmonary edema within 6 hours of transfusion. It is associated with antibodies in the donor blood reacting with recipient leukocyte antigens. This is the most common cause of death related to transfusion reactions. Treatment involves stopping the transfusion, administering oxygen, and providing aggressive respiratory support in approximately 75% of patients. Diuretic usage should be avoided.
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This question is part of the following fields:
- Haematology
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Question 37
Correct
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A 42-year-old man is found to have 'Reed-Sternberg cells' on his peripheral blood smear.
What is the MOST LIKELY diagnosis for this patient?Your Answer: Hodgkin lymphoma
Explanation:Reed-Sternberg cells are distinctive large cells that are typically observed in Hodgkin lymphoma. These cells are often found to have two nuclei or a nucleus with two lobes. Additionally, they possess noticeable nucleoli that resemble eosinophilic inclusion-like structures, giving them an appearance similar to that of an owl’s eye.
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This question is part of the following fields:
- Haematology
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Question 38
Incorrect
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A 65-year-old patient is presenting with upper gastrointestinal bleeding after receiving heparin. Your decision is to reverse the anticoagulation process.
What is the most appropriate option for reversing heparin?Your Answer: Vitamin K
Correct Answer: Protamine sulphate
Explanation:Protamine sulphate is a potent base that forms a stable salt complex with heparin, an acidic substance. This complex renders heparin inactive, making protamine sulphate a useful tool for neutralizing the effects of heparin. Additionally, protamine sulphate can be used to reverse the effects of LMWHs, although it is not as effective, providing only about two-thirds of the relative effect.
It is important to note that protamine sulphate also possesses its own weak intrinsic anticoagulant effect. This effect is believed to stem from its ability to inhibit the formation and activity of thromboplastin.
When administering protamine sulphate, it is typically done through slow intravenous injection. The dosage should be adjusted based on the amount of heparin that needs to be neutralized, the time that has passed since heparin administration, and the aPTT (activated partial thromboplastin time). As a general guideline, 1 mg of protamine can neutralize 100 IU of heparin. However, it is crucial to adhere to a maximum adult dose of 50 mg within a 10-minute period.
It is worth mentioning that protamine sulphate can have some adverse effects. It acts as a myocardial depressant, potentially leading to bradycardia (slow heart rate) and hypotension (low blood pressure). These effects may arise due to complement activation and leukotriene release.
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This question is part of the following fields:
- Haematology
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Question 39
Incorrect
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You assess a 68-year-old woman with chronic lymphocytic leukemia (CLL).
Which ONE of the following statements about CLL is accurate?Your Answer: A predominance of immature lymphocytes are seen on the blood film
Correct Answer: It is most commonly discovered as an incidental finding
Explanation:Chronic lymphocytic leukaemia (CLL) is the most common form of leukaemia in adults. It occurs when mature lymphocytes multiply uncontrollably. B-cell lineage accounts for about 95% of cases. CLL is typically slow-growing and is often discovered incidentally during routine blood tests. As the disease progresses, patients may experience swollen lymph nodes, enlarged liver and spleen, low red blood cell count, and increased susceptibility to infections. This condition primarily affects adult males, with over 75% of CLL patients being men over the age of 50.
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This question is part of the following fields:
- Haematology
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Question 40
Incorrect
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A 35-year-old man receives a blood transfusion. Shortly after the transfusion is started, he experiences a high body temperature, shivering, and severe shaking. Blood samples are collected for testing, and a diagnosis of bacterial infection related to the transfusion is confirmed.
What is the MOST LIKELY single organism responsible for this infection?Your Answer: Enterococcus faecalis
Correct Answer: Yersinia enterocolitica
Explanation:Transfusion transmitted bacterial infection is a rare complication that can occur during blood transfusion. It is more commonly associated with platelet transfusion, as platelets are stored at room temperature. Additionally, previously frozen components that are thawed using a water bath and red cell components stored for several weeks are also at a higher risk for bacterial infection.
Both Gram-positive and Gram-negative bacteria have been implicated in transfusion-transmitted bacterial infection, but Gram-negative bacteria are known to cause more severe illness and have higher rates of morbidity and mortality. Among the bacterial organisms, Yersinia enterocolitica is the most commonly associated with this type of infection. This particular organism is able to multiply at low temperatures and utilizes iron as a nutrient, making it well-suited for proliferation in blood stores.
The clinical features of transfusion-transmitted bacterial infection typically manifest shortly after the transfusion begins. These features include a high fever, chills and rigors, nausea and vomiting, tachycardia, hypotension, and even circulatory collapse.
If there is suspicion of a transfusion-transmitted bacterial infection, it is crucial to immediately stop the transfusion. Blood cultures and a Gram-stain should be requested to identify the specific bacteria causing the infection. Broad-spectrum antibiotics should be initiated promptly. Furthermore, the blood pack should be returned to the blood bank urgently for culture and Gram-stain analysis.
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This question is part of the following fields:
- Haematology
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Question 41
Incorrect
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You evaluate a 65-year-old woman with a diagnosis of chronic lymphocytic leukemia (CLL).
What is the PRIMARY factor that contributes to the immunodeficiency observed in this condition?Your Answer: Lymphopenia
Correct Answer: Hypogammaglobulinemia
Explanation:All individuals diagnosed with chronic lymphocytic leukaemia (CLL) experience some level of weakened immune system, although for many, it is not severe enough to have a significant impact on their health. Infections are the leading cause of death for 25-50% of CLL patients, with respiratory tract, skin, and urinary tract bacterial infections being the most prevalent. The primary factor contributing to the weakened immune system in CLL patients is hypogammaglobulinaemia, which is present in approximately 85% of all individuals with this condition.
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This question is part of the following fields:
- Haematology
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Question 42
Incorrect
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You evaluate a 30-year-old female patient with sickle-cell disease. She presents with dyspnea and pain in her lower extremities.
Which ONE statement about sickle-cell disease is accurate?Your Answer: It has a genotype HbAS
Correct Answer: Cholelithiasis is a recognised complication
Explanation:HbAS is known as Sickle cell trait, while HbSS is the genotype for Sickle-cell disease. Sickle-shaped red blood cells have a shorter lifespan of 10-20 days compared to the normal red blood cells that live for 90-120 days. Cholelithiasis, a complication of sickle-cell disease, occurs due to excessive bilirubin production caused by the breakdown of red blood cells. The inheritance pattern of sickle-cell disease is autosomal recessive. The disease is caused by a point mutation in the beta-globin chain of hemoglobin, resulting in the substitution of glutamic acid with valine at the sixth position. Individuals with one normal hemoglobin gene and one sickle gene have the genotype HbAS, which is commonly referred to as Sickle Cell trait.
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This question is part of the following fields:
- Haematology
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Question 43
Incorrect
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A 35-year-old woman with a history of sickle cell disease undergoes a blood transfusion. After one week, she experiences a slight fever and notices dark urine. Blood tests are ordered, revealing elevated bilirubin and LDH levels, as well as a positive Direct Antiglobulin Test (DAT).
What is the most probable cause of this transfusion reaction?Your Answer: ABO incompatibility
Correct Answer: Presence of low titre antibody
Explanation:Blood transfusion is a crucial treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion use, errors and adverse reactions still occur.
Delayed haemolytic transfusion reactions (DHTRs) typically occur 4-8 days after a blood transfusion, but can sometimes manifest up to a month later. The symptoms are similar to acute haemolytic transfusion reactions but are usually less severe. Patients may experience fever, inadequate rise in haemoglobin, jaundice, reticulocytosis, positive antibody screen, and positive Direct Antiglobulin Test (Coombs test). DHTRs are more common in patients with sickle cell disease who have received frequent transfusions.
These reactions are caused by the presence of a low titre antibody that is too weak to be detected during cross-match and unable to cause lysis at the time of transfusion. The severity of DHTRs depends on the immunogenicity or dose of the antigen. Blood group antibodies associated with DHTRs include those of the Kidd, Duffy, Kell, and MNS systems. Most DHTRs have a benign course and do not require treatment. However, severe haemolysis with anaemia and renal failure can occur, so monitoring of haemoglobin levels and renal function is necessary. If an antibody is detected, antigen-negative blood can be requested for future transfusions.
Here is a summary of the main transfusion reactions and complications:
1. Febrile transfusion reaction: Presents with a 1-degree rise in temperature from baseline, along with chills and malaise. It is the most common reaction and is usually caused by cytokines from leukocytes in transfused red cell or platelet components. Supportive treatment with paracetamol is helpful.
2. Acute haemolytic reaction: Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine. It is the most serious type of reaction and often occurs due to ABO incompatibility from administration errors. The transfusion should be stopped, and IV fluids should be administered. Diuretics may be required.
3. Delayed haemolytic reaction: This reaction typically occurs 4-8 days after a blood transfusion and presents with fever, anaemia, jaundice and haemoglobuinuria. Direct antiglobulin (Coombs) test positive. Due to low titre antibody too weak to detect in cross-match and unable to cause lysis at time of transfusion. Most delayed haemolytic reactions have a benign course and require no treatment. Monitor anaemia and renal function and treat as required.
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This question is part of the following fields:
- Haematology
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Question 44
Incorrect
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A 70-year-old woman comes in with complaints of tiredness and frequent nosebleeds. During the examination, she displays a widespread petechial rash and enlarged gums.
What is the SINGLE most probable diagnosis?Your Answer: Acute lymphocytic leukaemia (ALL)
Correct Answer: Acute myeloid leukaemia (AML)
Explanation:Leukaemic infiltrates in the gingiva are frequently observed in cases of acute myeloid leukaemia. This type of leukaemia primarily affects adults and is most commonly seen in individuals between the ages of 65 and 70. The typical presentation of acute myeloid leukaemia involves clinical symptoms that arise as a result of leukaemic infiltration in the bone marrow and other areas outside of the marrow. These symptoms may include anaemia (resulting in lethargy, pallor, and breathlessness), thrombocytopaenia (manifesting as petechiae, bruising, epistaxis, and bleeding), neutropenia (leading to increased susceptibility to infections), hepatosplenomegaly, and infiltration of the gingiva.
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This question is part of the following fields:
- Haematology
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Question 45
Incorrect
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A 32-year-old woman with a history of sickle-cell disease receives a blood transfusion for severe anemia. Four weeks later she arrives at the Emergency Department with a skin rash, high temperature, and diarrhea. Blood tests are ordered, revealing low levels of all blood cells and abnormal liver function.
What is the most suitable course of treatment for this patient?Your Answer: Methotrexate
Correct Answer: No effective treatment exists
Explanation:Blood transfusion is a potentially life-saving treatment that can provide great clinical benefits. However, it also carries several risks and potential problems. These include immunological complications, administration errors, infections, immune dilution, and transfusion errors. While there have been improvements in safety procedures and efforts to minimize the use of transfusion, errors and serious adverse reactions still occur and often go unreported.
One rare complication of blood transfusion is transfusion-associated graft-vs-host disease (TA-GVHD). This condition typically presents with fever, rash, and diarrhea 1-4 weeks after the transfusion. Laboratory findings may show pancytopenia and abnormalities in liver function. Unlike GVHD after marrow transplantation, TA-GVHD leads to severe marrow aplasia with a mortality rate exceeding 90%. Unfortunately, there are currently no effective treatments available for this condition, and survival is rare, with death usually occurring within 1-3 weeks of the first symptoms.
During a blood transfusion, viable T lymphocytes from the donor are transfused into the recipient’s body. In TA-GVHD, these lymphocytes engraft and react against the recipient’s tissues. However, the recipient is unable to reject the donor lymphocytes due to factors such as immunodeficiency, severe immunosuppression, or shared HLA antigens. Supportive management is the only option for TA-GVHD.
The following summarizes the main complications and reactions that can occur during a blood transfusion:
Complication Features Management
Febrile transfusion reaction
– Presents with a 1-degree rise in temperature from baseline, along with chills and malaise.
– Most common reaction, occurring in 1 out of 8 transfusions.
– Usually caused by cytokines from leukocytes in transfused red cell or platelet components.
– Supportive management, with the use of paracetamol for symptom relief.Acute haemolytic reaction
– Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine.
– Often accompanied by a feeling of ‘impending doom’.
– Most serious type of reaction, often due to ABO incompatibility caused by administration errors.
– Immediate action required: stop the transfusion, administer IV fluids, and consider diuretics if necessary.Delayed haemolytic reaction
– Typically occurs 4-8 days after a blood transfusion.
– Symptoms include fever, anemia and/or hyperbilirubinemia -
This question is part of the following fields:
- Haematology
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Question 46
Incorrect
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A 6-year-old girl presents with cold-like symptoms that have been present for over two weeks. She is originally from South America. Her mother reports that she has been extremely tired and has been complaining of various aches and pains. During the examination, enlarged lymph nodes are found in her neck, and splenomegaly is detected. She has multiple petechiae on her legs and arms. Her blood test results are as follows:
Hemoglobin: 7.4 g/dl (11.5-15.5 g/dl)
Mean Corpuscular Volume (MCV): 80 fl (75-87 fl)
Platelets: 34 x 109/l (150-400 x 109/l)
White Cell Count (WCC): 34.4 x 109/l (4-11 x 109/l)
What is the most likely diagnosis for this patient?Your Answer: Aplastic anaemia
Correct Answer: Acute lymphoblastic leukaemia (ALL)
Explanation:Acute lymphoblastic leukaemia (ALL) is the most common type of leukaemia that occurs in childhood, typically affecting children between the ages of 2 and 5 years. The symptoms of ALL can vary, but many children initially experience an acute illness that may resemble a common cold or viral infection. Other signs of ALL include general weakness and fatigue, as well as muscle, joint, and bone pain. Additionally, children with ALL may have anaemia, unexplained bruising and petechiae, swelling (oedema), enlarged lymph nodes (lymphadenopathy), and an enlarged liver and spleen (hepatosplenomegaly).
In patients with ALL, a complete blood count typically reveals certain characteristics. These include anaemia, which can be either normocytic or macrocytic. Approximately 50% of patients with ALL have a low white blood cell count (leukopaenia), with a white cell count below 4 x 109/l. On the other hand, around 60% of patients have a high white blood cell count (leukocytosis), with a white cell count exceeding 10 x 109/l. In about 25% of cases, there is an extreme elevation in white blood cell count (hyperleukocytosis), with a count surpassing 50 x 109/l. Additionally, patients with ALL often have a low platelet count (thrombocytopaenia).
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This question is part of the following fields:
- Haematology
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Question 47
Incorrect
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You assess a patient who has recently been diagnosed with chronic myeloid leukemia (CML).
Which ONE statement about CML is accurate?Your Answer: Patients are generally symptomatic during the ‘chronic stage’
Correct Answer: The Philadelphia chromosome is present in over 80% of cases
Explanation:Chronic myeloid leukaemia (CML) is a type of blood disorder that arises from an abnormal pluripotent haemopoietic stem cell. The majority of CML cases, more than 80%, are caused by a cytogenetic abnormality called the Philadelphia chromosome. This abnormality occurs when there is a reciprocal translocation between the long arms of chromosomes 9 and 22.
CML typically develops slowly over a period of several years, known as the chronic stage. During this stage, patients usually do not experience any symptoms, and it is often discovered incidentally through routine blood tests. Around 90% of CML cases are diagnosed during this stage. In the bone marrow, less than 10% of the white cells are immature blasts.
Symptoms start to appear when the CML cells begin to expand, which is known as the accelerated stage. Approximately 10% of cases are diagnosed during this stage. Between 10 and 30% of the blood cells in the bone marrow are blasts at this point. Common clinical features during this stage include tiredness, fatigue, fever, night sweats, abdominal distension, left upper quadrant pain (splenic infarction), splenomegaly (enlarged spleen), hepatomegaly (enlarged liver), easy bruising, gout (due to rapid cell turnover), and hyperviscosity (which can lead to complications like stroke, priapism, etc.).
In some cases, a small number of patients may present with a blast crisis, also known as the blast stage. During this stage, more than 30% of the blood cells in the bone marrow are immature blast cells. Patients in this stage are generally very ill, experiencing severe constitutional symptoms such as fever, weight loss, and bone pain, as well as infections and bleeding tendencies.
Laboratory findings in CML include a significantly elevated white cell count (often greater than 100 x 109/l), a left shift with an increased number of immature leukocytes, mild to moderate normochromic, normocytic anaemia, variable platelet counts (low, normal, or elevated), presence of the Philadelphia chromosome in more than 80% of cases, and elevated levels of serum uric acid and alkaline phosphatase.
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This question is part of the following fields:
- Haematology
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Question 48
Correct
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You review a patient with sickle-cell disease and a history of multiple previous painful episodes. The patient informs you that two other individuals in his family also have sickle-cell disease.
What is the mode of inheritance for sickle-cell disease?Your Answer: Autosomal recessive
Explanation:Sickle-cell disease is a blood disorder that is inherited in an autosomal recessive manner. It is characterized by the production of abnormal red blood cells that have a sickle shape. These abnormal cells are triggered by various factors such as low oxygen levels, dehydration, stress, and infection. The disease is caused by a specific mutation in the beta-globin chain of hemoglobin, resulting in the substitution of glutamic acid with valine at the sixth position. The gene responsible for this mutation is located on chromosome 11.
On the other hand, sickle-cell trait refers to the carrier state of the disease. Individuals with sickle-cell trait have one normal allele and one abnormal allele. Both alleles are co-dominant, meaning that both normal and abnormal hemoglobin are produced. As a result, individuals with sickle-cell trait do not experience the same severity of symptoms as those with sickle-cell disease.
When both parents are carriers of the sickle-cell trait, there is a 50% chance that their child will also be an unaffected carrier, a 25% chance that the child will be unaffected, and a 25% chance that the child will develop sickle-cell disease. This is because the inheritance of the disease follows the principles of autosomal recessive inheritance.
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This question is part of the following fields:
- Haematology
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Question 49
Incorrect
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A 35-year-old woman with a history of sickle cell disease undergoes a blood transfusion. After one week, she experiences a slight fever and notices dark urine. Blood tests are ordered, revealing elevated bilirubin and LDH levels, as well as a positive Direct Antiglobulin Test (DAT).
What is the most suitable course of treatment for this patient?Your Answer: Administer adrenaline and IV fluids
Correct Answer: Monitor renal function and haemoglobin
Explanation:Blood transfusion is a crucial treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion use, errors and adverse reactions still occur.
Delayed haemolytic transfusion reactions (DHTRs) typically occur 4-8 days after a blood transfusion, but can sometimes manifest up to a month later. The symptoms are similar to acute haemolytic transfusion reactions but are usually less severe. Patients may experience fever, inadequate rise in haemoglobin, jaundice, reticulocytosis, positive antibody screen, and positive Direct Antiglobulin Test (Coombs test). DHTRs are more common in patients with sickle cell disease who have received frequent transfusions.
These reactions are caused by the presence of a low titre antibody that is too weak to be detected during cross-match and unable to cause lysis at the time of transfusion. The severity of DHTRs depends on the immunogenicity or dose of the antigen. Blood group antibodies associated with DHTRs include those of the Kidd, Duffy, Kell, and MNS systems. Most DHTRs have a benign course and do not require treatment. However, severe haemolysis with anaemia and renal failure can occur, so monitoring of haemoglobin levels and renal function is necessary. If an antibody is detected, antigen-negative blood can be requested for future transfusions.
Here is a summary of the main transfusion reactions and complications:
1. Febrile transfusion reaction: Presents with a 1-degree rise in temperature from baseline, along with chills and malaise. It is the most common reaction and is usually caused by cytokines from leukocytes in transfused red cell or platelet components. Supportive treatment with paracetamol is helpful.
2. Acute haemolytic reaction: Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine. It is the most serious type of reaction and often occurs due to ABO incompatibility from administration errors. The transfusion should be stopped, and IV fluids should be administered. Diuretics may be required.
3. Delayed haemolytic reaction: This reaction typically occurs 4-8 days after a blood transfusion and presents with fever, anaemia, jaundice and haemoglobuinuria. Direct antiglobulin (Coombs) test positive. Due to low titre antibody too weak to detect in cross-match and unable to cause lysis at time of transfusion. Most delayed haemolytic reactions have a benign course and require no treatment. Monitor anaemia and renal function and treat as required.
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This question is part of the following fields:
- Haematology
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Question 50
Incorrect
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A 35-year-old patient with a history of exhaustion and weariness has a complete blood count scheduled. The complete blood count reveals that she has normocytic anemia.
Which of the following is the LEAST probable underlying diagnosis?Your Answer: Acute haemorrhage
Correct Answer: Hypothyroidism
Explanation:Anaemia can be categorized based on the size of red blood cells. Microcytic anaemia, characterized by a mean corpuscular volume (MCV) of less than 80 fl, can be caused by various factors such as iron deficiency, thalassaemia, anaemia of chronic disease (which can also be normocytic), sideroblastic anaemia (which can also be normocytic), lead poisoning, and aluminium toxicity (although this is now rare and mainly affects haemodialysis patients).
On the other hand, normocytic anaemia, with an MCV ranging from 80 to 100 fl, can be attributed to conditions like haemolysis, acute haemorrhage, bone marrow failure, anaemia of chronic disease (which can also be microcytic), mixed iron and folate deficiency, pregnancy, chronic renal failure, and sickle-cell disease.
Lastly, macrocytic anaemia, characterized by an MCV greater than 100 fl, can be caused by factors such as B12 deficiency, folate deficiency, hypothyroidism, reticulocytosis, liver disease, alcohol abuse, myeloproliferative disease, myelodysplastic disease, and certain drugs like methotrexate, hydroxyurea, and azathioprine.
It is important to understand the different causes of anaemia based on red cell size as this knowledge can aid in the diagnosis and management of this condition.
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This question is part of the following fields:
- Haematology
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