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  • Question 1 - A 26-year-old female with a past medical history of asthma presents to the...

    Correct

    • A 26-year-old female with a past medical history of asthma presents to the Emergency Department with acute dyspnea, accompanied by a tingling sensation in her tongue and a rash after consuming a meal containing shellfish. Her symptoms improve with intramuscular epinephrine and nebulized salbutamol. What is the most effective diagnostic test to confirm if this event was caused by anaphylaxis?

      Your Answer: Serum tryptase

      Explanation:

      After an acute episode of anaphylaxis, the levels of serum tryptase may increase and stay elevated for as long as 12 hours.

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

      The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

      Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

    • This question is part of the following fields:

      • Immunology/Allergy
      1337.1
      Seconds
  • Question 2 - A 23-year-old woman comes to her doctor after finishing her hepatitis B vaccination...

    Correct

    • A 23-year-old woman comes to her doctor after finishing her hepatitis B vaccination series and wants to verify her immunity status. What is the best test to confirm her status?

      Your Answer: Antibody to hepatitis B surface antigen (HBsAg; anti-HBs)

      Explanation:

      Hepatitis B Markers: Understanding Their Significance

      Hepatitis B is a viral infection that affects the liver. There are several markers used to diagnose and monitor the disease, including antibody to hepatitis B surface antigen (anti-HBs), hepatitis B envelope antigen (HBeAg), anti-hepatitis B envelope antibody (anti-HBe), hepatitis B virus (HBV) DNA, and immunoglobulin M (IgM) anti-hepatitis B core antigen (anti-HBc).

      Anti-HBs is produced after a resolved infection or effective vaccination and is the only HBV antibody marker present after vaccination. High-risk individuals should have their anti-HBs level checked after completing their primary course of vaccination.

      HBeAg is a marker of infectivity and can serve as a marker of active replication in chronic hepatitis. It is not present following vaccination. Anti-HBe is a predictor of long-term clearance of HBV in patients undergoing antiviral therapy and indicates lower levels of HBV and, therefore, lower infectivity. Both HBeAg and anti-HBe remain negative following vaccination.

      HBV DNA is used to quantify viral load in a patient with proven acute or chronic hepatitis B infection. A positive result suggests not only the likelihood of active hepatitis but also that the disease is much more infectious as the virus is actively replicating. HBV DNA remains negative following vaccination.

      The presence of IgM anti-HBc is diagnostic of an acute or recently acquired infection. It remains negative following vaccination.

    • This question is part of the following fields:

      • Immunology/Allergy
      519.2
      Seconds
  • Question 3 - What is the most appropriate next step in managing a 40-year-old woman who...

    Correct

    • What is the most appropriate next step in managing a 40-year-old woman who presents with yellowing of the skin and eyes, fatigue, and intense itching, and has a history of coeliac disease? Her test results show elevated bilirubin, positive anti-mitochondrial antibodies, and normal kidney function.

      Your Answer: Ursodeoxycholic acid

      Explanation:

      Treatment Options for Primary Biliary Cholangitis

      Primary biliary cholangitis (PBC) is an inflammatory condition that affects middle-aged, overweight women. The most common symptoms are fatigue and pruritis, along with elevated alkaline phosphatase levels. Ursodeoxycholic acid is the preferred treatment for PBC as it slows disease progression. Cholestyramine can effectively control pruritis, but it does not affect overall mortality in PBC. Liver transplantation is reserved for cases where medical alternatives have failed. Loratadine is not indicated for PBC, and prednisolone is used in the treatment of autoimmune hepatitis, which is a different condition.

    • This question is part of the following fields:

      • Immunology/Allergy
      29.9
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  • Question 4 - A 32-year-old woman presents to her General Practitioner with a 4-week history of...

    Correct

    • A 32-year-old woman presents to her General Practitioner with a 4-week history of diarrhoea, opening her bowels up to 2–3 times per day. She also complains of intermittent bloating and abdominal pain mostly prior to opening her bowels. There is no history of fever or vomiting and she has no past medical history of note. She returned from Thailand two weeks ago.
      Stool microscopy: trophozoites and cysts are seen.
      Given the likely diagnosis, what is the recommended management for this patient?
      Select the SINGLE most appropriate management from the list below.

      Your Answer: Metronidazole

      Explanation:

      Antibiotics for Diarrhoeal Illnesses: Understanding the Appropriate Treatment

      Giardiasis is a diarrhoeal illness caused by the protozoa Giardia lamblia, which is spread through contaminated food, water or faeces. The disease can last up to six weeks and presents with symptoms such as abdominal bloating, flatulence or malabsorption. Metronidazole is the preferred treatment for giardiasis due to its effectiveness and improved compliance.

      Doxycycline is used to treat cholera, a severe disease that causes watery diarrhoea and dehydration. However, the chronic duration of symptoms and presence of parasitic organisms make cholera unlikely.

      Ciprofloxacin is used to treat urinary-tract infections and some diarrhoeal illnesses such as cholera and Campylobacter jejuni infections. However, Campylobacter is usually self-limiting and has a much shorter duration of illness, making it an unlikely diagnosis.

      Clindamycin is not classically used to treat giardiasis and should be used with caution due to the increased risk of developing antibiotic-associated colitis and opportunistic infections such as Clostridium difficile.

      Co-amoxiclav may be used to treat intra-abdominal infections such as biliary sepsis, but it is not indicated for giardiasis.

      In summary, understanding the appropriate use of antibiotics for diarrhoeal illnesses is crucial in providing effective treatment and avoiding unnecessary risks.

    • This question is part of the following fields:

      • Immunology/Allergy
      76.4
      Seconds
  • Question 5 - A 12-year-old boy with a history of eczema and asthma suddenly experiences breathlessness,...

    Correct

    • A 12-year-old boy with a history of eczema and asthma suddenly experiences breathlessness, nausea, and swelling of the face after eating a chicken skewer at a party. A 999 call is made, and his friends report that his skin is covered in raised red bumps and his lips are turning blue. What is the most appropriate immediate management for this patient?

      Your Answer: Intramuscular (IM) adrenaline 0.5 mg (1 : 1000)

      Explanation:

      Emergency Management of Anaphylaxis: Medications and Interventions

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that requires immediate intervention. The following medications and interventions are commonly used in the emergency management of anaphylaxis:

      Intramuscular (IM) adrenaline 0.5 mg (1 : 1000): This is the first-line treatment for anaphylaxis and should be administered immediately. It can be repeated every 5 minutes as needed, guided by vital signs, until the patient is stable.

      Intravenous (IV) adrenaline 0.5 ml of 1 : 10 000: This is used in severe cases of anaphylaxis that do not respond to initial treatment. It should only be administered by experienced specialists and titrated carefully.

      IV chlorphenamine in 0.9% saline (500 ml): Chlorphenamine is no longer recommended for initial emergency anaphylaxis management.

      Reassurance and breathing exercises: These may be appropriate for a panic attack, but anaphylaxis requires immediate medical intervention.

      Salbutamol: While bronchodilator therapy may be considered after initial resuscitation, the most important treatment for anaphylaxis is oxygen administration and IM adrenaline.

      It is important to recognize the signs and symptoms of anaphylaxis and to act quickly to administer appropriate medications and interventions.

    • This question is part of the following fields:

      • Immunology/Allergy
      26.7
      Seconds
  • Question 6 - A 32-year-old man experiences severe facial and tongue swelling following administration of the...

    Incorrect

    • A 32-year-old man experiences severe facial and tongue swelling following administration of the Japanese encephalitis vaccine. He receives 500mcg of intramuscular adrenaline immediately and is placed in a supine position with elevated legs while receiving high-flow oxygen. Despite the initial dose of adrenaline, his facial swelling persists and his blood pressure drops to 82/54 mmHg. How long should the healthcare provider wait before administering a second dose of adrenaline?

      Your Answer: 15 minutes

      Correct Answer: 5 minutes

      Explanation:

      Adrenaline can be administered every 5 minutes during the management of anaphylaxis.

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

      The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

      Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

    • This question is part of the following fields:

      • Immunology/Allergy
      53.7
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  • Question 7 - A 26-year-old woman with a known peanut allergy arrives at the emergency department...

    Correct

    • A 26-year-old woman with a known peanut allergy arrives at the emergency department after experiencing sudden symptoms while dining at a nearby restaurant. She reports feeling flushed, dizzy, and itchy. Upon examination, the patient exhibits widespread wheezing in her chest. Her blood pressure is 80/57 mmHg, and her heart rate is 120 beats per minute. Despite receiving two doses of IM adrenaline, the patient's condition does not improve. What is the next best course of action?

      Your Answer: Seek expert help for consideration of IV adrenaline

      Explanation:

      In cases of refractory anaphylaxis where two doses of IM adrenaline have failed to improve the patient’s condition, the Resuscitation Council guidelines (2021) recommend seeking expert help for consideration of low-dose IV adrenaline infusion. Therefore, the correct answer is to seek expert help for IV adrenaline administration under guidance. Administering adenosine, setting up an adrenaline infusion without specialist help, waiting for 5 or 10 minutes before giving another dose of IM adrenaline are all incorrect options. It is important to follow the guidelines and seek expert help for appropriate management of refractory anaphylaxis.

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

      The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

      Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

    • This question is part of the following fields:

      • Immunology/Allergy
      18.2
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  • Question 8 - A 20-year-old woman is enjoying a shrimp stir-fry at a restaurant when she...

    Incorrect

    • A 20-year-old woman is enjoying a shrimp stir-fry at a restaurant when she suddenly experiences tongue swelling and tightness in her chest. Her partner notices her wheezing and calls for an ambulance. The woman is admitted to the hospital and undergoes necessary tests. She receives treatment for anaphylaxis, and her symptoms improve. After being monitored overnight on the ward, what crucial factor must be taken into account when determining if it is safe to discharge her the following morning?

      Your Answer: The patient's peak expiratory flow rate at the time of discharge

      Correct Answer: The patient's remaining symptoms and his response to adrenaline

      Explanation:

      When discharging patients who have experienced anaphylaxis, a risk-stratified approach should be taken. The patient’s response to adrenaline and their symptoms are important factors to consider. The UK Resuscitation Council guidelines suggest that patients may be considered for fast-track discharge if they have had a good response to a single dose of adrenaline within 30 minutes of the reaction, their symptoms have completely resolved, they have been trained on how to use adrenaline auto-injectors, and there is adequate supervision following discharge. While the patient’s peak expiratory flow rate and serum tryptase levels should be measured, they are not specifically advised for risk-stratifying patients for discharge post-anaphylaxis according to the UKRC guidelines. Spirometry is also not specifically recommended for this purpose. However, patients with severe asthma or those who experienced severe respiratory compromise during the anaphylactic reaction should be observed for at least 12 hours after symptom resolution.

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

      The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

      Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

    • This question is part of the following fields:

      • Immunology/Allergy
      22.2
      Seconds
  • Question 9 - What is the pathophysiological mechanism of hyperacute allograft rejection, which is one of...

    Incorrect

    • What is the pathophysiological mechanism of hyperacute allograft rejection, which is one of the significant risks associated with transplantation and can potentially endanger the patient's life?

      Your Answer: Class II human leukocyte antigen (HLA) antibody activation, monocyte adhesion and thrombosis

      Correct Answer: Class I HLA antibody activation, granulocyte adhesion and thrombosis

      Explanation:

      Misconceptions about the Pathophysiology of Allograft Rejection

      There are several misconceptions about the pathophysiology of allograft rejection. One of them is that hyper-acute allograft rejection is solely caused by class I HLA antibody activation, granulocyte adhesion, and thrombosis. While these factors do play a role, the ultimate result of hyper-acute rejection is thrombosis of the vessels and graft ischaemia, which presents itself as graft swelling once perfusion is reinstated.

      Another misconception is that donor MHC I antigens react with host CD8 resulting in direct cytotoxic damage, which is a sequence in the pathophysiology of acute rejection response, not hyper-acute rejection.

      Class II HLA antibodies are often thought to be the primary source of activation of the coagulation cascade, but this is not the case. Monocytes are also not activated in this process.

      Interstitial fibrosis is often thought to be a mechanism of acute rejection, but it is actually the end-stage mechanism of chronic graft rejection.

      Lastly, lymphocyte, killer T-cell, and cytokine activation are often thought to be part of the mechanism of hyper-acute allograft rejection, but they are actually part of the mechanism of action in acute allograft rejection.

      It is important to have a clear understanding of the pathophysiology of allograft rejection to properly diagnose and treat patients.

    • This question is part of the following fields:

      • Immunology/Allergy
      34.6
      Seconds
  • Question 10 - A 32-year-old woman visits the Urgent Treatment Centre as she has discovered a...

    Incorrect

    • A 32-year-old woman visits the Urgent Treatment Centre as she has discovered a tick-like insect attached to her ankle. She had been hiking in a nearby forest earlier today and is worried because her sister was diagnosed with Lyme disease after a similar experience.
      There are no signs of inflammation or infection in the skin surrounding the tick.
      What is the most suitable next step in managing this patient?

      Your Answer: Prescribe prophylactic antibiotics against Lyme disease

      Correct Answer: Remove the tick using fine-tipped tweezers, grasping the tick by the head as close to the skin as possible and pulling firmly upwards

      Explanation:

      Proper Tick Removal Techniques and Treatment Options

      Ticks are common parasites that can cause a range of illnesses, including Lyme disease. It is important to remove ticks properly to prevent infection. The best way to remove a tick is by using fine-tipped tweezers, grasping the tick as close to the skin as possible and pulling upwards firmly. This will prevent the body from detaching and leaving mouthparts in the skin. After removal, the bite area should be cleaned with antiseptic or soap and water. Irrigating the area with saline solution is not recommended as it may lead to partial removal of the tick. Prophylactic antibiotics are not recommended for tick bites, but antibiotics may be prescribed if a patient is diagnosed with Lyme disease. Vaccines for Lyme disease are not currently available. If there is a clear indication of infection, oral antibiotics may be prescribed. Proper tick removal and treatment can help prevent the spread of tick-borne illnesses.

    • This question is part of the following fields:

      • Immunology/Allergy
      558.7
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  • Question 11 - A 45-year-old male dental practice nurse is admitted for elective surgery. During induction...

    Incorrect

    • A 45-year-old male dental practice nurse is admitted for elective surgery. During induction with a general anaesthetic, he develops tachycardia, rash and diffuse wheeze. He mentioned that he had a rash when assisting with an anaesthetic case at work.
      Which of the following is the most likely diagnosis?
      Select the SINGLE most likely diagnosis from the list below. Select ONE option only.

      Your Answer: Serum sickness

      Correct Answer: Anaphylaxis

      Explanation:

      Understanding Allergic Reactions: Types and Symptoms

      Allergic reactions can take many forms, each with its own set of symptoms and causes. Anaphylaxis is a severe and potentially life-threatening reaction that can occur in response to drugs, insect stings, or certain foods. It is characterized by rapid onset of airway, breathing, and circulation problems, as well as skin and mucosal changes. Systemic mastocytosis is another type of allergic reaction that can cause symptoms such as itching, abdominal cramping, and even shock. Pseudoallergy, on the other hand, can mimic true allergies but has different underlying causes, such as altered histamine metabolism or food intolerance.

      Serum sickness is a self-limited allergic reaction that occurs after exposure to foreign proteins. It is a type III hypersensitivity reaction that can cause fever, skin rash, and joint symptoms. Contact dermatitis is an inflammatory skin reaction that can be caused by either an irritant or an allergen. Allergic contact dermatitis is a type IV delayed hypersensitivity reaction that occurs after sensitization and subsequent re-exposure to an allergen, while irritant contact dermatitis is an inflammatory response that occurs after damage to the skin by chemicals.

      It is important to recognize the symptoms of these different types of allergic reactions and seek medical attention if necessary. Anaphylaxis, in particular, is a medical emergency that can lead to death if not treated promptly. By understanding the different types of allergic reactions and their causes, we can take steps to prevent them and manage their symptoms effectively.

    • This question is part of the following fields:

      • Immunology/Allergy
      7.7
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  • Question 12 - A 63-year-old librarian complains of a persistent cough and difficulty breathing during physical...

    Incorrect

    • A 63-year-old librarian complains of a persistent cough and difficulty breathing during physical activity. A chest CT scan reveals a ground-glass appearance. What is the most frequently linked mechanism responsible for this reaction?

      Your Answer: Anaphylaxis

      Correct Answer: Type III hypersensitivity reaction

      Explanation:

      Hypersensitivity Reactions: Types and Examples

      Hypersensitivity reactions are immune responses that can cause tissue damage and inflammation. There are four types of hypersensitivity reactions, each with different mechanisms and clinical presentations.

      Type I hypersensitivity reaction is an immediate hypersensitivity reaction mediated by IgE in response to an innocuous environmental antigen. Examples of such reactions are allergic rhinitis and systemic urticaria.

      Type II hypersensitivity reaction is an antibody-mediated reaction. Cellular injury may result from complement activation, antibody-dependent cell-mediated cytotoxicity or phagocytosis. Examples include incompatible blood transfusions, haemolytic disease of the newborn and autoimmune haemolytic anaemias.

      Type III hypersensitivity reaction is an immune complex-mediated reaction. Immune complexes are lattices of antibody and antigen. When these are not cleared from the circulation, they may trigger an inflammatory response. An example of this type of reaction is extrinsic allergic alveolitis, otherwise known as ‘bird fancier’s lung’, a hypersensitivity pneumonitis caused by exposure to bird droppings.

      Type IV hypersensitivity reaction is a delayed hypersensitivity reaction involving T helper cells that become activated upon contact with an antigen, which results in a clonal expansion over 1–2 weeks. Repeated exposure to the antigen results in cytokine release from sensitised T-cells, leading to macrophage-induced phagocytosis.

      Anaphylaxis is a type I-mediated hypersensitivity reaction, involving the release of inflammatory mediators (such as histamine), which precipitate vasodilatation and oedema. Anaphylaxis is characterised by the rapid onset of respiratory and circulatory compromise.

      Understanding the different types of hypersensitivity reactions is important for diagnosis and treatment. Treatment may involve removal of the source of hypersensitivity, immunosuppressive therapy, or administration of epinephrine in the case of anaphylaxis.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 13 - A child is admitted with wheeze and an urticarial rash, which began 10...

    Incorrect

    • A child is admitted with wheeze and an urticarial rash, which began 10 minutes after ingestion of amoxicillin for a chest infection.
      Which type of hypersensitivity reaction is this?

      Your Answer: Type 4

      Correct Answer: Type 1

      Explanation:

      Types of Hypersensitivity Reactions and Their Mechanisms

      Hypersensitivity reactions are exaggerated immune responses that can cause tissue damage and disease. There are five types of hypersensitivity reactions, each with a different mechanism and clinical presentation.

      Type 1 hypersensitivity reactions are mediated by immunoglobulin E (IgE) and mast cell degranulation, leading to the release of histamine and other mediators. This type of reaction is responsible for allergies and anaphylaxis and is treated with antihistamines, epinephrine, and steroids.

      Type 2 hypersensitivity reactions are antibody-mediated and involve the interaction of antibodies with antigens on target cells. Examples include haemolytic anaemia of the newborn and Goodpasture Syndrome.

      Type 3 hypersensitivity reactions are immune complex-mediated and occur when immune complexes are deposited in tissues, leading to inflammation. Examples include rheumatoid arthritis and systemic lupus erythematosus.

      Type 4 hypersensitivity reactions are delayed and involve the activation of sensitised T-helper cells, leading to the accumulation of macrophages and cytotoxic T-cells. Examples include chronic transplant rejection and contact dermatitis.

      Type 5 hypersensitivity reactions are receptor-mediated or autoimmune and occur when antibodies bind to cell surface receptors. Examples include Grave’s disease and myasthenia gravis.

      Understanding the mechanisms of hypersensitivity reactions is important for diagnosis and treatment.

    • This question is part of the following fields:

      • Immunology/Allergy
      8.2
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  • Question 14 - After being stung by a bee, a 20-year-old man visits his General Practitioner...

    Correct

    • After being stung by a bee, a 20-year-old man visits his General Practitioner with swollen face and lips, along with wheezing. He is experiencing breathing difficulties and his blood pressure is 83/45 mmHg as per manual reading.
      What would be the most suitable course of action to manage this situation?

      Your Answer: Give 1 : 1 000 intramuscular (im) adrenaline

      Explanation:

      Administering Adrenaline for Anaphylaxis: Dosage and Route

      Anaphylaxis is a severe medical emergency that requires immediate treatment. The administration of adrenaline is crucial in managing anaphylactic shock. However, the dosage and route of administration depend on the severity of the symptoms.

      For mild symptoms, such as skin rash or itching, the administration of iv hydrocortisone and chlorpheniramine is sufficient. But if the symptoms progress to involve the airways or circulation, adrenaline should be given as soon as possible. The recommended dosage for intramuscular (im) adrenaline is 1:1000.

      It’s important to note that the dosage for cardiac arrest is different, and it’s given intravenously (iv) at a concentration of 1:10,000. However, routine use of iv adrenaline is not recommended unless the healthcare provider is skilled and experienced in its use.

      Hydrocortisone, even by an iv route, takes several hours to have an effect and is no longer deemed to be part of emergency treatment of anaphylaxis. Therefore, it’s not an appropriate course of action for rapidly life-threatening situations.

      In summary, administering adrenaline for anaphylaxis requires careful consideration of the dosage and route of administration. It’s crucial to act quickly and seek emergency medical attention to prevent fatal outcomes.

    • This question is part of the following fields:

      • Immunology/Allergy
      30.1
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  • Question 15 - Which one of the following statements regarding allergy testing is inaccurate? ...

    Incorrect

    • Which one of the following statements regarding allergy testing is inaccurate?

      Your Answer: Both irritants and allergens may be tested for using skin patch testing

      Correct Answer: Skin prick testing should be read after 48 hours

      Explanation:

      The results of skin prick testing can be interpreted after 15-20 minutes, while skin patch testing requires 48 hours after the patch is removed to be read.

      Types of Allergy Tests

      Allergy tests are used to determine if a person has an allergic reaction to a particular substance. There are several types of allergy tests available, each with its own advantages and limitations. The most commonly used test is the skin prick test, which is easy to perform and inexpensive. Drops of diluted allergen are placed on the skin, and a needle is used to pierce the skin. A wheal will typically develop if a patient has an allergy. This test is useful for food allergies and pollen.

      Another type of allergy test is the radioallergosorbent test (RAST), which determines the amount of IgE that reacts specifically with suspected or known allergens. Results are given in grades from 0 (negative) to 6 (strongly positive). This test is useful for food allergies, inhaled allergens (e.g. pollen), and wasp/bee venom.

      Skin patch testing is useful for contact dermatitis. Around 30-40 allergens are placed on the back, and irritants may also be tested for. The patches are removed 48 hours later, and the results are read by a dermatologist after a further 48 hours. Blood tests may be used when skin prick tests are not suitable, for example if there is extensive eczema or if the patient is taking antihistamines. Overall, allergy tests are an important tool in diagnosing and managing allergies.

    • This question is part of the following fields:

      • Immunology/Allergy
      18.4
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  • Question 16 - A 19-year-old young woman is enjoying a meal at a Chinese restaurant to...

    Incorrect

    • A 19-year-old young woman is enjoying a meal at a Chinese restaurant to celebrate her birthday. Despite having a nut allergy, the restaurant has taken precautions to ensure her safety. However, while trying a friend's chicken dish, she unknowingly ingested peanuts and experiences a severe allergic reaction, including difficulty breathing and facial swelling. Thankfully, her friend has an EpiPen® and administers it before calling for an ambulance. Although her symptoms improve, she remains unwell and struggling to breathe. Her friend remembers that a second EpiPen® can be used if necessary. When is it appropriate to administer the second dose of adrenaline?

      Your Answer: 2 minutes

      Correct Answer: 5 minutes

      Explanation:

      Adrenaline can be administered every 5 minutes in the management of anaphylaxis. It is recommended that individuals with a history of anaphylaxis carry two auto-injectors with them in case a second dose is needed.

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

      The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

      Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 17 - A 20-year-old man is brought to the emergency department after experiencing a possible...

    Incorrect

    • A 20-year-old man is brought to the emergency department after experiencing a possible allergic reaction to seafood he ate at a restaurant. He administered his adrenaline autoinjector and received an additional dose of intramuscular adrenaline from the paramedics.
      Upon examination, his temperature is 37.8ºC, heart rate is 130 beats/min, and blood pressure is 88/50 mmHg. He has a respiratory rate of 30 breaths/min and oxygen saturation of 93% on room air.
      What is the next course of action in managing this patient?

      Your Answer: Salbutamol nebuliser

      Correct Answer: Intravenous adrenaline infusion

      Explanation:

      For patients with refractory anaphylaxis, which is characterized by persistent respiratory and/or cardiovascular problems despite receiving 2 doses of intramuscular adrenaline, the recommended next step is to start an intravenous adrenaline infusion. Administering further intramuscular adrenaline is not recommended. Intravenous chlorphenamine and hydrocortisone are also no longer recommended in the updated guidelines for anaphylaxis management.

      Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

      The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

      Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 18 - A 38-year-old, atopic, healthcare worker presents with red wheals and itchy hands within...

    Incorrect

    • A 38-year-old, atopic, healthcare worker presents with red wheals and itchy hands within 20 minutes of wearing latex gloves.
      Which of the following is the most appropriate investigation to perform to establish a diagnosis?

      Your Answer: Skin-prick testing

      Correct Answer: Radioallergosorbent test (RAST)

      Explanation:

      Diagnosis of Latex Allergy: Tests and Considerations

      Latex allergy is an immediate hypersensitivity reaction that is IgE-mediated. The diagnosis of latex allergy involves various tests and considerations. The first choice test for results on latex-specific IgE is the Radioallergosorbent test (RAST). Skin-prick testing with latex extracts is sensitive, specific, and rapid, but carries the risk of anaphylaxis. Skin-patch testing is useful in identifying specific allergens in patients with type IV hypersensitivity to latex products. A gluten exclusion diet would not be the most appropriate investigation if latex allergy were suspected. Complement-mediated and immune complex reactions typically produce vascular damage, so bullae and petechiae would predominate in the skin. In summary, the diagnosis of latex allergy requires careful consideration of the type of hypersensitivity reaction and appropriate testing.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 19 - A 7-year-old child visits the pediatrician with symptoms of recurrent sinusitis. After reviewing...

    Incorrect

    • A 7-year-old child visits the pediatrician with symptoms of recurrent sinusitis. After reviewing the child's medical history, the pediatrician discovers that the child has had multiple respiratory and gastrointestinal infections in the past. The pediatrician suspects a possible primary immunoglobulin deficiency and wants to conduct further tests.
      What investigation is necessary to confirm a primary immunoglobulin deficiency in this case?

      Your Answer: Polymerase chain reaction

      Correct Answer: Measurement of immunoglobulin G (IgG), IgA and IgM

      Explanation:

      Common Medical Tests and Their Uses

      Immunoglobulin Measurement: This test measures the levels of immunoglobulin G (IgG), IgA, and IgM proteins in response to infection. Low levels of these proteins can lead to increased susceptibility to infections.

      Flow Cytometry: This test is used to differentiate between different T cell populations and count the number of cells in a sample. It works by passing cells through a laser beam and analyzing the amount of light scatter to identify cell size and granularity.

      Human Leukocyte Antigen (HLA) Typing: This test matches patients and donors for cord blood or bone marrow transplants by analyzing proteins used by the immune system to differentiate between self and non-self.

      Patch Test: This test diagnoses delayed type IV hypersensitivity reactions by applying test substances to the skin and examining it for any inflammatory response.

      Polymerase Chain Reaction: This test amplifies DNA segments for functional analysis of genes, diagnosis of hereditary diseases, and detection of infectious diseases.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 20 - A woman presents with an area of dermatitis on her right ankle. She...

    Incorrect

    • A woman presents with an area of dermatitis on her right ankle. She suspects she may have a nickel allergy. What is the most appropriate test to confirm this suspicion?

      Your Answer: Nickel IgM levels

      Correct Answer: Skin patch test

      Explanation:

      Types of Allergy Tests

      Allergy tests are used to determine if a person has an allergic reaction to a particular substance. There are several types of allergy tests available, each with its own advantages and limitations. The most commonly used test is the skin prick test, which is easy to perform and inexpensive. Drops of diluted allergen are placed on the skin, and a needle is used to pierce the skin. A wheal will typically develop if a patient has an allergy. This test is useful for food allergies and pollen.

      Another type of allergy test is the radioallergosorbent test (RAST), which determines the amount of IgE that reacts specifically with suspected or known allergens. Results are given in grades from 0 (negative) to 6 (strongly positive). This test is useful for food allergies, inhaled allergens (e.g. pollen), and wasp/bee venom.

      Skin patch testing is useful for contact dermatitis. Around 30-40 allergens are placed on the back, and irritants may also be tested for. The patches are removed 48 hours later, and the results are read by a dermatologist after a further 48 hours. Blood tests may be used when skin prick tests are not suitable, for example if there is extensive eczema or if the patient is taking antihistamines. Overall, allergy tests are an important tool in diagnosing and managing allergies.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 21 - A social worker in their 40s has been diagnosed with hepatitis C infection.
    Which...

    Incorrect

    • A social worker in their 40s has been diagnosed with hepatitis C infection.
      Which test will conclusively establish the presence of this infection?

      Your Answer: Hepatitis B virus (HBV) DNA

      Correct Answer: HCV RNA

      Explanation:

      Hepatitis C Testing Methods

      Hepatitis C is a viral infection that affects the liver. There are several testing methods available to diagnose and monitor hepatitis C infection.

      Quantitative HCV RNA tests measure the amount of hepatitis C virus in the blood, which is also known as the viral load. This test is the most sensitive and accurate way to confirm a hepatitis C diagnosis, especially when viral loads are low.

      Screening tests for co-infection with other viruses, such as hepatitis B or HIV, may be done but do not assist in the diagnosis of hepatitis C infection itself.

      Anti-hepatitis C virus (HCV) serologic screening involves an enzyme immunoassay (EIA) that can detect antibodies to the virus. However, this test cannot distinguish between acute and chronic infection and may yield false-positive results.

      HCV genotyping is a helpful tool for predicting the likelihood of response and duration of treatment. It is used in adult, non-immunocompromised patients with known chronic HCV infection.

      Immunoglobulin M (IgM) anti-HAV screening tests for co-infection with hepatitis A virus may be done but do not assist in the diagnosis of hepatitis C infection itself.

      Hepatitis C Testing Methods

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 22 - A newly qualified nurse in her 50s at the local hospital undergoes vaccination...

    Incorrect

    • A newly qualified nurse in her 50s at the local hospital undergoes vaccination against hepatitis B. The following results are obtained three months after completion of the primary course:

      Result Anti-HBs: 10 - 100 mIU/ml

      Reference An antibody level of >100 mIU/ml indicates a good immune response with protective immunity

      What should be done next?

      Your Answer: Do a HIV test

      Correct Answer: Give one further dose of hepatitis B vaccine

      Explanation:

      Understanding Hepatitis B: Causes, Symptoms, Complications, and Management

      Hepatitis B is a type of virus that contains double-stranded DNA and is transmitted through exposure to infected blood or body fluids. It can also be passed from mother to child during childbirth. The incubation period for this virus is between 6 to 20 weeks. Symptoms of hepatitis B include fever, jaundice, and elevated liver transaminases. Complications of this infection include chronic hepatitis, fulminant liver failure, hepatocellular carcinoma, glomerulonephritis, polyarteritis nodosa, and cryoglobulinemia.

      To prevent hepatitis B, children born in the UK are now vaccinated as part of the routine immunization schedule. At-risk groups who should also be vaccinated include healthcare workers, intravenous drug users, sex workers, close family contacts of an individual with hepatitis B, individuals receiving regular blood transfusions, chronic kidney disease patients, prisoners, and chronic liver disease patients. However, around 10-15% of adults may fail to respond or respond poorly to the vaccine.

      Testing for anti-HBs is only recommended for those at risk of occupational exposure and patients with chronic kidney disease. The interpretation of anti-HBs levels is as follows: an anti-HBs level of >100 indicates an adequate response, 10-100 indicates a suboptimal response, and <10 indicates a non-responder. Management of hepatitis B includes the use of pegylated interferon-alpha, which reduces viral replication in up to 30% of chronic carriers. Other antiviral medications such as tenofovir, entecavir, and telbivudine are also used to suppress viral replication.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 23 - A 27-year-old man presents to the Genitourinary Medicine Clinic with an 8-day history...

    Correct

    • A 27-year-old man presents to the Genitourinary Medicine Clinic with an 8-day history of dysuria and creamy urethral discharge. He has never had urethral discharge before and is very concerned. His past medical history includes childhood asthma and he is otherwise well with no allergies. During the consultation, he discloses that he had unprotected sexual intercourse two weeks ago.
      On examination, his observations are within normal limits. His abdomen is soft and nontender with no palpable lymphadenopathy. There are no visible rashes. High urethral swabs are taken which show the presence of Gram-negative diplococci.
      Given the likely diagnosis, what is the most appropriate management for this patient?
      Select the SINGLE most appropriate management from the list below.
      Select ONE option only.

      Your Answer: Ceftriaxone

      Explanation:

      Common Antibiotics Used in the Treatment of Sexually Transmitted Infections

      Sexually transmitted infections (STIs) are a common health concern worldwide. Antibiotics are often used in the treatment of STIs, but the choice of antibiotic depends on the specific infection. Here are some common antibiotics used in the treatment of STIs:

      Ceftriaxone: This antibiotic is used to treat gonorrhoea, a sexually transmitted disease caused by the bacterium Neisseria gonorrhoeae. Symptoms include urethral or vaginal discharge and dysuria. The current British Society for Sexual Health and HIV guidelines recommend a single dose of intramuscular ceftriaxone for the treatment of gonorrhoea.

      Azithromycin: This antibiotic is used to treat chlamydia, the most common sexually transmitted disease. Chlamydia may be asymptomatic or cause symptoms such as mucoid or mucopurulent urethral discharge and dysuria.

      Benzylpenicillin: This antibiotic is used to treat syphilis, a sexually transmitted infection caused by the spirochaete Treponema pallidum. The disease has three stages of infection – primary, secondary and tertiary.

      Doxycycline: This antibiotic is also used to treat chlamydia or syphilis, but it is not used in the treatment of gonorrhoea.

      Metronidazole: This antibiotic is used to treat bacterial vaginosis and trichomoniasis. Neither infection is caused by the bacterium Neisseria gonorrhoeae.

      It is important to seek medical attention if you suspect you have an STI, as early diagnosis and treatment can prevent complications and transmission to others.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 24 - A 22-year-old man comes to his General Practitioner complaining of frequent watery diarrhoea,...

    Incorrect

    • A 22-year-old man comes to his General Practitioner complaining of frequent watery diarrhoea, abdominal pain, flatulence and nausea. Upon stool analysis, an elevated osmotic gap is detected with a pH < 6. The hydrogen breath test is positive.
      What is the most probable diagnosis?

      Your Answer: Cows’ milk protein allergy

      Correct Answer: Lactose intolerance

      Explanation:

      Based on the patient’s symptoms and test results, it is likely that they have lactose intolerance. This diagnosis is supported by an increase in stool osmolality and a positive hydrogen breath test, which can be confirmed through dietary testing. While bowel malignancy is a possibility, additional symptoms such as rectal bleeding and weight loss would typically be present. Cows’ milk protein allergy is unlikely due to the patient’s age and the positive hydrogen breath test. Inflammatory bowel disease may have similar symptoms, but additional indicators such as weight loss, fever, and anemia would be present. Irritable bowel syndrome is not the most likely diagnosis and should only be considered after other possibilities have been ruled out.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 25 - A 48-year-old man presents to the emergency department with his spouse. He is...

    Incorrect

    • A 48-year-old man presents to the emergency department with his spouse. He is experiencing significant swelling of his tongue and lips, rendering him unable to speak. His wife reports that his symptoms have worsened during their wait, and she is unsure of the cause as he has no known allergies. However, she does mention that he was recently prescribed a new medication by his primary care physician.
      Which of the following medications is the most probable culprit?

      Your Answer: Amlodipine

      Correct Answer: Ramipril

      Explanation:

      Although it is possible for the man to have been prescribed any of the medications listed, it is evident that he is experiencing angioedema, as indicated by the swelling of his tongue and lips. Ramipril, an ACE inhibitor, is the medication most commonly associated with this side effect. Even if the patient has no history of allergies or negative reactions to ACE inhibitors, angioedema can still occur. While the likelihood of this happening is low, it is important to keep in mind due to the large number of patients taking this type of medication and the potential complications associated with angioedema.

      Angiotensin-converting enzyme (ACE) inhibitors are commonly used as the first-line treatment for hypertension and heart failure in younger patients. However, they may not be as effective in treating hypertensive Afro-Caribbean patients. These inhibitors are also used to treat diabetic nephropathy and for secondary prevention of ischaemic heart disease. The mechanism of action of ACE inhibitors is to inhibit the conversion of angiotensin I to angiotensin II. They are metabolized in the liver through phase 1 metabolism.

      ACE inhibitors may cause side effects such as cough, which occurs in around 15% of patients and may occur up to a year after starting treatment. This is thought to be due to increased bradykinin levels. Angioedema may also occur up to a year after starting treatment. Hyperkalaemia and first-dose hypotension are other potential side effects, especially in patients taking diuretics. ACE inhibitors should be avoided during pregnancy and breastfeeding, and caution should be exercised in patients with renovascular disease, aortic stenosis, or hereditary or idiopathic angioedema.

      Patients receiving high-dose diuretic therapy (more than 80 mg of furosemide a day) are at an increased risk of hypotension when taking ACE inhibitors. Before initiating treatment, urea and electrolytes should be checked, and after increasing the dose, a rise in creatinine and potassium may be expected. Acceptable changes include an increase in serum creatinine up to 30% from baseline and an increase in potassium up to 5.5 mmol/l. Patients with undiagnosed bilateral renal artery stenosis may experience significant renal impairment. The current NICE guidelines provide a flow chart for the management of hypertension.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 26 - A 15-year-old student presents to his General Practitioner with symptoms of tingling and...

    Correct

    • A 15-year-old student presents to his General Practitioner with symptoms of tingling and irritation in his mouth and throat on two or three occasions in the past year. Most recently, he suffered from swelling of his throat and difficulty breathing after receiving a local anaesthetic for tooth extraction at the dentist. He reports that his father died of a suspected allergic reaction when he was 42 years old.
      Investigations reveal the following:
      Investigation Result Normal value
      Haemoglobin (Hb) 129 g/l 135–175 g/l
      White cell count (WCC) 6.8 × 109/l 4.0–11.0 × 109/l
      Platelets (PLT) 341 × 109/l 150–400 × 109/l
      Erythrocyte sedimentation rate (ESR) 5 mm/hour 1–20 mm/hour
      Patch testing Mild reaction to grass pollens
      C4 Low
      C3 Normal
      Which of the following is the most likely diagnosis in this case?

      Your Answer: Hereditary angio-oedema

      Explanation:

      The correct diagnosis for this patient is hereditary angio-oedema, also known as hereditary angioneurotic oedema. This is an autosomal dominant disorder caused by a congenital deficiency of the C1 inhibitor protein, which is mapped to chromosome 11. In some cases, C1 inhibitor levels are normal but have reduced function. Symptoms typically appear during adolescence and include recurrent attacks of pain, tingling, or itching, particularly around the mouth and pharynx, which may be triggered by increased circulating sex steroids or dental anaesthesia using lidocaine. Diagnosis is made by measuring complement levels, with C4 always low during attacks and often low in between, while C3 and C1q are always normal. Treatment involves using C1 inhibitor concentrate during acute attacks and danazol to increase C4 levels and reduce the frequency and severity of attacks. ACE inhibitors are contraindicated due to the risk of bradykinin accumulation. Acquired angio-oedema, which is caused by an acquired C1 inhibitor deficiency and is associated with lymphoproliferative disorders, is a different condition. Protein C deficiency is a genetic prothrombotic condition that does not explain this patient’s symptoms, and somatisation disorder is unlikely given the clear test abnormalities related to the patient’s symptoms.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 27 - A 15-year-old boy presents to his General Practitioner as he has been suffering...

    Incorrect

    • A 15-year-old boy presents to his General Practitioner as he has been suffering from recurrent infections for the last few months. He has also been losing weight. He has taken four courses of antibiotics in the last six months for various respiratory tract infections. He also experienced an episode of shingles that took a few years to clear after becoming secondarily infected.
      On examination, he is pale and underweight, with a body mass index (BMI) of 17.5 kg/m2. He has fine, downy hair on his back, abdomen and forearms. His temperature is 35.9 °C. His blood pressure is 90/45 mmHg while his pulse is 52 bpm.
      What is the most likely cause of this patient’s immunodeficiency?

      Your Answer: Cytomegalovirus (CMV) infection

      Correct Answer: Malnutrition

      Explanation:

      Differential diagnosis of immunodeficiency in an adolescent with weight loss and recurrent infection

      Malnutrition, primary immunodeficiency, cytomegalovirus (CMV) infection, human immunodeficiency virus (HIV) infection, and diabetes mellitus are among the possible causes of immunodeficiency in an adolescent with weight loss and recurrent infection. Malnutrition can suppress the immune system and is often associated with anorexia nervosa, which can be characterized by a very low body mass index (BMI), lanugo hair growth, hypothermia, bradycardia, and hypotension. Primary immunodeficiency syndromes, which are usually inherited as single-gene disorders, tend to present in infancy or early childhood with poor growth and weight gain and recurrent, prolonged, severe, or atypical infections. Cytomegalovirus (CMV) is a herpes virus that can cause serious complications in immunocompromised individuals or congenital cases, but is usually asymptomatic in immunocompetent individuals. Human immunodeficiency virus (HIV) infection can result in immunodeficiency by infecting and destroying CD4 cells, and should be suspected in individuals with prolonged, severe, or recurrent infections, particularly if they are a member of a high-risk group. Diabetes mellitus, especially type I, can also cause dysfunction of the immune system and increase the risk of infection. However, in an adolescent with a low BMI, type II diabetes would be very unlikely.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 28 - A toddler is due his measles, mumps and rubella (MMR) vaccine. The toddler's...

    Incorrect

    • A toddler is due his measles, mumps and rubella (MMR) vaccine. The toddler's mother wants to have a bit of information regarding the vaccine. What type of vaccine is the MMR?

      Your Answer: A conjugate vaccine

      Correct Answer: A live attenuated vaccine

      Explanation:

      Types of Vaccines and Their Definitions

      Live Attenuated Vaccine:
      This type of vaccine involves injecting a small sample of the virus into the body, allowing the immune system to fight it and create an immune response against it for future attacks. The MMR vaccine is an example of a live attenuated vaccine.

      Conjugate Vaccine:
      Conjugate vaccines are created by combining a weak antigen with a strong antigen to produce a stronger immune response. Typically, a polysaccharide is joined with a strong protein to create this type of vaccine.

      Inactivated Vaccine:
      Inactivated vaccines, such as the pertussis and hepatitis A vaccines, contain dead pathogens that cannot cause disease but still stimulate an immune response.

      Subunit Vaccine:
      Subunit vaccines only contain the antigenic component of the pathogen. However, there is no guarantee that immunological memory will be achieved appropriately. The pneumococcal vaccine is an example of a subunit vaccine.

      Toxoid Vaccine:
      Toxoid vaccines are toxins that have been deactivated but still stimulate an immune response from the immune system. Examples include the diphtheria and tetanus vaccines.

      Understanding the Different Types of Vaccines

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 29 - A 6-year-old boy is brought to the paediatrician for evaluation of recurrent sinus...

    Incorrect

    • A 6-year-old boy is brought to the paediatrician for evaluation of recurrent sinus infections, tonsillitis and urinary tract infections. Laboratory analysis of his blood revealed severe lymphopenia, and his lymphocytes did not respond to mitogens. His levels of serum antibodies were abnormally diminished, as were B-cell and T-cell functions.
      What was the most likely diagnosis?

      Your Answer: Wiskott–Aldrich syndrome (WAS)

      Correct Answer: Severe combined immunodeficiency disease (SCID)

      Explanation:

      Severe combined immunodeficiency disease (SCID) is a condition that affects both B- and T-cell immunity, making patients more susceptible to viral, bacterial, mycobacterial, or fungal infections. It typically presents at a young age due to the severity of the immunodeficiency. SCID has two major forms: an X-linked recessive mutation in the γ-chain subunit of a cytokine receptor, which is more common in males, and an autosomal recessive mutation in the genes that encode the enzyme adenosine deaminase, which leads to toxic accumulation of nucleotides in differentiating lymphocytes, especially those in the T-cell lineage. Based on the patient’s female gender, young age at presentation, history of infections, and diminished B and T cells with low serum immunoglobulins, autosomal recessive SCID is the most likely diagnosis. Other conditions such as acquired immunodeficiency syndrome (AIDS), di George syndrome (dGS), systemic lupus erythematosus (SLE), and Wiskott–Aldrich syndrome (WAS) have different pathogenic mechanisms and are less likely to be the cause of the patient’s presentation.

    • This question is part of the following fields:

      • Immunology/Allergy
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  • Question 30 - A 32-year-old man presents to his General Practitioner with a 3-day history of...

    Incorrect

    • A 32-year-old man presents to his General Practitioner with a 3-day history of flu-like symptoms and jaundice. He is a prison doctor. He sustained a needlestick injury six weeks ago from a high-risk patient after performing venepuncture. He immediately presented to the Emergency Department (ED) and was given a booster vaccination and post-exposure prophylaxis (PPE) treatment for human immunodeficiency virus (HIV). He is awaiting blood-borne virus (BBV) screening.
      What is the most likely diagnosis?
      Select ONE option only.

      Your Answer:

      Correct Answer: Hepatitis C

      Explanation:

      Overview of Viral Hepatitis: Types, Transmission, and Risk Factors

      Viral hepatitis is a group of infectious diseases that affect the liver and can cause serious health complications. There are five main types of viral hepatitis: A, B, C, D, and E. Each type has its own unique characteristics, transmission routes, and risk factors.

      Hepatitis A is transmitted via the faecal-oral route and is most common in developing countries. It can cause symptoms similar to other types of viral hepatitis, but is less severe. Hepatitis B is transmitted via blood-to-blood and bloody fluid contact, and is most prevalent in migrant populations from certain regions. Hepatitis C is highly infectious and is commonly transmitted through shared needles or other injecting paraphernalia used for illicit drugs. Hepatitis D is a rare type of viral hepatitis that can only occur in patients with existing hepatitis B infection. Hepatitis E is also transmitted via the faecal-oral route, but is less common and usually only causes mild illness.

      If a healthcare professional sustains a needlestick injury or other high-risk exposure to hepatitis C, they should have blood tests taken at specific intervals to confirm active infection. Hepatitis B vaccination is recommended for individuals working in high-risk clinical areas, and can also prevent hepatitis D infection. Chronic infection is rare for hepatitis E, unless the affected person is immunocompromised.

      Understanding the different types of viral hepatitis, their transmission routes, and risk factors is important for preventing and managing these infections.

    • This question is part of the following fields:

      • Immunology/Allergy
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