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.

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.

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.

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.

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.

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.

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 has been an improvement in safety procedures and a reduction in transfusion use, errors and serious adverse reactions still occur and often go unreported.

Mild allergic reactions during blood transfusion are relatively common and typically occur within a few minutes of starting the transfusion. These reactions happen when patients have antibodies that react with foreign plasma proteins in the transfused blood components. Symptoms of mild allergic reactions include urticaria, Pruritus, and hives.

Anaphylaxis, on the other hand, is much rarer and occurs when an individual has previously been sensitized to an allergen present in the blood. When re-exposed to the allergen, the body releases IgE or IgG antibodies, leading to severe symptoms such as bronchospasm, laryngospasm, abdominal pain, nausea, vomiting, hypotension, shock, and loss of consciousness. Anaphylaxis can be fatal.

Mild allergic reactions can be managed by slowing down the transfusion rate and administering antihistamines. If there is no progression after 30 minutes, the transfusion may continue. Patients who have experienced repeated allergic reactions to transfusion should be given pre-treatment with chlorpheniramine. In cases of anaphylaxis, the transfusion should be stopped immediately, and the patient should receive oxygen, adrenaline, corticosteroids, and antihistamines following the ALS protocol.

The table below summarizes the main transfusion reactions and complications, along with their features and management:

Complication | Features | Management
Febrile transfusion reaction | 1 degree rise in temperature, chills, malaise | Supportive care, paracetamol
Acute haemolytic reaction | Fever, chills, pain at transfusion site, nausea, vomiting, dark urine | STOP THE TRANSFUSION, administer IV fluids, diuretics if necessary
Delayed haemolytic reaction | Fever, anaemia, jaundice, haemoglobinuria | Monitor anaemia and renal function, treat as required
Allergic reaction | Urticaria, Pruritus, hives | Symptomatic treatment with ant

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).

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.

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.

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.

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).

Immunoglobulin light chains that are present in the urine are commonly known as Bence-Jones proteins (BJP). These proteins are primarily observed in individuals with multiple myeloma, although they can occasionally be detected in Waldenström macroglobulinemia, although this is a rare occurrence. It is important to note that BJP in the urine is not observed in the other conditions mentioned in this question.

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.

Protamine sulphate is a potent base that forms a stable salt complex with heparin, an acidic substance. This complex is inactive and is used to counteract 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.

Apart from its ability to neutralize heparin, protamine sulphate also possesses a weak intrinsic anticoagulant effect. This is believed to be due to its inhibition of the formation and activity of thromboplastin.

To administer protamine sulphate, it is slowly injected intravenously. The dosage should be adjusted based on the amount of heparin to be neutralized, the time elapsed since heparin administration, and the aPTT. For every 100 IU of heparin, 1 mg of protamine is required for neutralization. However, the maximum adult dose within a 10-minute period should not exceed 50 mg.

It is important to note that protamine sulphate has additional effects on the body. It acts as a depressant on the heart muscle and may lead to bradycardia and hypotension. These effects are caused by complement activation and the release of leukotrienes.

Auer rods are small, needle-shaped structures that can be found within the cytoplasm of blast cells. These structures have a distinct eosinophilic appearance. While they are most frequently observed in cases of acute myeloid leukemia, they can also be present in high-grade myelodysplastic syndromes and myeloproliferative disorders.

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.

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.

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

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.

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.

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.

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.

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.

Methaemoglobinaemia is a condition that can be caused by nitrates, including amyl nitrite.

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%.

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.

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.

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

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.

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.