Anaphylaxis — MCQs
A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:
A man takes peanut and develops tongue swelling, neck swelling, stridor, hoarseness of voice. What is the probable diagnosis?
A child with a known peanut allergy accidentally ingests a food containing peanuts and develops urticaria, vomiting, and wheezing within minutes. What is the first-line treatment?
What is a characteristic feature of Systemic Juvenile Idiopathic Arthritis?
A patient presents with thrombocytopenia, eczema, and recurrent infections. What is the most probable diagnosis?
A child presents with delayed separation of the umbilical cord, leukocytosis, Down syndrome, and recurrent infections. What is the most likely diagnosis?
Which of the following is a feature of Henoch-Schönlein purpura?
Excessive crying is a potential adverse reaction following which vaccination?
Which of the following is NOT a criterion for Juvenile Rheumatoid Arthritis?
A child presents with a constellation of findings including fever, disabling arthritis, rash, and blindness. What is the MOST likely diagnosis?
Anaphylaxis Indian Medical PG Practice Questions and MCQs
Question 1: A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:
- A. Bradycardia
- B. Dysrhythmia
- C. Increased peripheral vascular resistance
- D. Hypotension (Correct Answer)
Explanation: ***Hypotension*** - **Hypotension** is a hallmark cardiovascular sign of anaphylaxis, occurring due to widespread **vasodilation** and increased vascular permeability. - This symptom is often profound and unresponsive to initial fluid resuscitation due to the ongoing systemic release of inflammatory mediators. *Bradycardia* - While bradycardia can occur in some rare cases of anaphylaxis (e.g., **vasovagal response**), **tachycardia** is the more common cardiac response due to compensatory mechanisms. - It is not a primary or consistent indicator of anaphylaxis, making it less helpful for diagnosis in this context. *Dysrhythmia* - **Dysrhythmias** can occur during anaphylaxis due to myocardial ischemia or electrolyte imbalances, but they are not a direct or consistent diagnostic feature. - Their presence often reflects severe compromise or co-existing conditions rather than being a primary anaphylactic sign. *Increased peripheral vascular resistance* - Anaphylaxis is characterized by a significant **decrease in peripheral vascular resistance** due to mast cell and basophil degranulation releasing vasodilatory mediators like histamine. - Therefore, an increase in peripheral vascular resistance would contradict the pathophysiology of anaphylaxis.
Question 2: A man takes peanut and develops tongue swelling, neck swelling, stridor, hoarseness of voice. What is the probable diagnosis?
- A. FB in larynx
- B. Angioneurotic edema (Correct Answer)
- C. Parapharyngeal abscess
- D. FB bronchus
Explanation: Andioneurotic edema - The combination of **tongue swelling**, **neck swelling**, **stridor**, and **hoarseness of voice** following peanut ingestion is highly suggestive of **angioneurotic edema**, a severe allergic reaction that can lead to airway obstruction [1]. - This is a life-threatening condition requiring immediate medical intervention, often associated with generalized **anaphylaxis** when triggered by allergens [2]. *FB in larynx* - While a **foreign body (FB) in the larynx** can cause stridor and hoarseness, the widespread swelling of the tongue and neck points away from a localized laryngeal obstruction [3]. - A laryngeal FB would typically be associated with a more sudden onset of choking and coughing, not diffuse edema [3]. *Parapharyngeal abscess* - A **parapharyngeal abscess** would typically present with **fever**, **severe throat pain**, and **trismus** (difficulty opening the mouth), which are not mentioned in this scenario. - The acute, rapid onset of symptoms after peanut consumption is inconsistent with the slower progression of an abscess. *FB bronchus* - A **foreign body in the bronchus** would primarily cause **coughing**, **wheezing**, and possibly **respiratory distress**, often unilateral, rather than severe global swelling of the tongue and neck. - Inspiratory stridor and hoarseness are more indicative of upper airway involvement than bronchial obstruction.
Question 3: A child with a known peanut allergy accidentally ingests a food containing peanuts and develops urticaria, vomiting, and wheezing within minutes. What is the first-line treatment?
- A. Oral antihistamines
- B. Subcutaneous epinephrine
- C. Intramuscular epinephrine (Correct Answer)
- D. High-dose corticosteroids
Explanation: ***Intramuscular epinephrine*** - This patient is experiencing **anaphylaxis**, characterized by rapid-onset **urticaria**, **vomiting** (gastrointestinal involvement), and **wheezing** (respiratory involvement). - **Epinephrine** is the **first-line treatment** for anaphylaxis due to its alpha-1 agonist effects (vasoconstriction to counteract hypotension and reduce angioedema) and beta-2 agonist effects (bronchodilation to relieve wheezing). Intramuscular administration ensures rapid absorption and systemic effect. *Oral antihistamines* - While antihistamines can help manage cutaneous symptoms like **urticaria** and **itching**, they do not address the life-threatening respiratory or cardiovascular symptoms of anaphylaxis. - They are considered **adjunctive therapy** for mild allergic reactions but are not sufficient as first-line treatment for anaphylaxis. *Subcutaneous epinephrine* - **Subcutaneous administration** is historical and **not recommended** for anaphylaxis because it has a slower and less predictable absorption compared to intramuscular injection. - The delay in onset of action can be critical in a rapidly progressing anaphylactic reaction. *High-dose corticosteroids* - **Corticosteroids** act too slowly to be useful as a primary treatment for acute anaphylaxis, as their effects take several hours to manifest. - They are used as **adjunctive therapy** to prevent protracted or biphasic reactions, but not for the initial management of acute symptoms.
Question 4: What is a characteristic feature of Systemic Juvenile Idiopathic Arthritis?
- A. Uveitis is a feature
- B. It occurs after 16 years of age
- C. NSAIDs are contraindicated
- D. RA factor is negative (Correct Answer)
Explanation: ### Explanation **Systemic Juvenile Idiopathic Arthritis (sJIA)**, also known as Still’s disease, is a unique subtype of JIA characterized by prominent extra-articular features. **Why the correct answer is right:** In sJIA, the **Rheumatoid Factor (RF) is characteristically negative**. Unlike the polyarticular subtype (which can be RF positive), sJIA is considered an autoinflammatory disease rather than a classic autoimmune disease. Diagnosis is clinical, based on the presence of arthritis in one or more joints associated with (or preceded by) a fever of at least 2 weeks' duration that is daily ("quotidian") for at least 3 days, accompanied by features like an evanescent salmon-pink rash, lymphadenopathy, or serositis. **Analysis of Incorrect Options:** * **A. Uveitis is a feature:** This is incorrect for sJIA. Chronic anterior uveitis is a classic complication of **Oligoarticular JIA** (especially if ANA positive). Uveitis is very rare in the systemic subtype. * **B. It occurs after 16 years of age:** By definition, JIA must have an onset **before the age of 16**. If similar symptoms occur after 16, it is termed Adult-Onset Still’s Disease (AOSD). * **C. NSAIDs are contraindicated:** This is false. NSAIDs are often the **first-line** symptomatic treatment for pain and fever in JIA, though systemic steroids or biologics (IL-1 and IL-6 inhibitors) are usually required for definitive control. **High-Yield Clinical Pearls for NEET-PG:** * **Fever Pattern:** Classic "Quotidian" fever (spikes once daily, usually in the evening, returning to baseline). * **Laboratory Markers:** Marked leukocytosis, thrombocytosis, and highly elevated ESR/CRP. * **Ferritin:** Extremely high ferritin levels are common and can signal the onset of **Macrophage Activation Syndrome (MAS)**, a life-threatening complication of sJIA. * **Biologics of Choice:** Tocilizumab (IL-6 inhibitor) and Anakinra/Canakinumab (IL-1 inhibitors).
Question 5: A patient presents with thrombocytopenia, eczema, and recurrent infections. What is the most probable diagnosis?
- A. Wiskott Aldrich syndrome (Correct Answer)
- B. A beta gammaglobulinemia
- C. Chediak Higashi syndrome
- D. Lazy leukocyte syndrome
Explanation: **Explanation:** The classic triad of **thrombocytopenia, eczema, and recurrent infections** is the hallmark presentation of **Wiskott-Aldrich Syndrome (WAS)**. 1. **Why A is Correct:** WAS is an X-linked recessive disorder caused by a mutation in the *WASp* gene, which leads to defects in the actin cytoskeleton of hematopoietic cells. This results in: * **Thrombocytopenia:** Characteristically presents with **micro-platelets** (small size), leading to bleeding tendencies (e.g., petechiae, melena). * **Eczema:** Typically develops within the first year of life. * **Immunodeficiency:** Defects in both T-cells and B-cells lead to recurrent infections with encapsulated bacteria and opportunistic pathogens. 2. **Why the others are Incorrect:** * **B. Agammaglobulinemia (Bruton’s):** Presents with recurrent pyogenic infections due to B-cell deficiency, but lacks thrombocytopenia and eczema. * **C. Chediak-Higashi Syndrome:** Characterized by **oculocutaneous albinism**, giant cytoplasmic granules in neutrophils, and peripheral neuropathy. * **D. Lazy Leukocyte Syndrome:** A defect in neutrophil chemotaxis and mobility; patients have neutropenia but not the classic triad of WAS. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** X-linked Recessive (mostly males). * **Lab Finding:** Low IgM, normal/high IgA and IgE, and **small-sized platelets** (pathognomonic). * **Complications:** High risk of **autoimmune hemolytic anemia** and **B-cell lymphomas**. * **Treatment:** Hematopoietic stem cell transplant (HSCT) is the definitive cure.
Question 6: A child presents with delayed separation of the umbilical cord, leukocytosis, Down syndrome, and recurrent infections. What is the most likely diagnosis?
- A. Leukocyte Adhesion Deficiency (Correct Answer)
- B. Neonatal Sepsis
- C. Histiocytosis-X
- D. All of the above
Explanation: ### Explanation **Correct Option: A. Leukocyte Adhesion Deficiency (LAD)** **Why it is correct:** Leukocyte Adhesion Deficiency (Type 1) is a primary immunodeficiency caused by a defect in the **CD18 subunit of $\beta_2$-integrins**. This defect prevents neutrophils from adhering to the vascular endothelium and migrating into tissues (diapedesis). * **Delayed separation of the umbilical cord:** This is the classic hallmark of LAD. Normally, neutrophils infiltrate the cord stump to facilitate its detachment; in LAD, the absence of neutrophils at the site leads to delayed separation (often >30 days). * **Leukocytosis:** Because neutrophils cannot leave the bloodstream to enter tissues, they accumulate in the blood, leading to persistent, marked neutrophilic leukocytosis. * **Recurrent Infections:** Patients suffer from skin and mucosal infections (e.g., omphalitis, periodontitis) characterized by a **lack of pus formation** despite high white cell counts. * **Association:** While not a primary feature, LAD has been documented in case reports involving children with Down syndrome. **Why other options are incorrect:** * **B. Neonatal Sepsis:** While sepsis causes leukocytosis and infections, it does not explain the specific anatomical delay in umbilical cord separation. * **C. Histiocytosis-X (Langerhans Cell Histiocytosis):** This typically presents with seborrheic-like skin rashes, lytic bone lesions, and hepatosplenomegaly, rather than a specific defect in cord separation or integrin function. **High-Yield Clinical Pearls for NEET-PG:** * **LAD Type 1:** Defect in **CD18** (Integrins). * **LAD Type 2:** Defect in **Sialyl-Lewis X** (Selectins); presents with short stature and intellectual disability. * **Key Triad:** Delayed cord separation + Recurrent "cold" infections (no pus) + Extreme neutrophilia. * **Diagnosis:** Confirmed by **Flow Cytometry** showing decreased expression of CD11/CD18.
Question 7: Which of the following is a feature of Henoch-Schönlein purpura?
- A. Palpable purpura and arthralgia (Correct Answer)
- B. Palpable purpura
- C. Occurs only in elderly persons
- D. Thrombocytopenia
Explanation: **Explanation:** **Henoch-Schönlein Purpura (HSP)**, now commonly referred to as **IgA Vasculitis**, is the most common systemic vasculitis in children. It is a small-vessel vasculitis characterized by the deposition of IgA-dominant immune complexes. 1. **Why Option A is correct:** The classic clinical tetrad of HSP includes **palpable purpura** (without thrombocytopenia), **arthralgia/arthritis**, abdominal pain, and renal disease (hematuria). Palpable purpura is the hallmark finding, typically distributed over the buttocks and lower extremities. Arthralgia occurs in about 75% of cases, most commonly affecting the knees and ankles. Therefore, Option A represents the most comprehensive clinical feature among the choices. 2. **Why other options are incorrect:** * **Option B:** While palpable purpura is a feature, Option A is a more complete description of the systemic nature of the disease. * **Option C:** HSP is primarily a **pediatric disease**, with a peak incidence between ages 3 and 10 years. It is rare in infants and less common in adults. * **Option D:** A defining feature of HSP is that it is a **non-thrombocytopenic purpura**. The platelet count is characteristically normal or even elevated (thrombocytosis). This distinguishes it from Immune Thrombocytopenic Purpura (ITP). **Clinical Pearls for NEET-PG:** * **Preceding Event:** Often follows an Upper Respiratory Tract Infection (URTI), specifically Group A *Streptococcus*. * **Renal Involvement:** The most serious long-term complication is **HSP nephritis**, which is histologically identical to IgA Nephropathy (Berger’s disease). * **Gastrointestinal:** Intussusception (typically ileo-ileal) is a known surgical complication. * **Diagnosis:** Primarily clinical; skin biopsy shows **leukocytoclastic vasculitis** with IgA deposition on immunofluorescence.
Question 8: Excessive crying is a potential adverse reaction following which vaccination?
- A. Polio
- B. DPT (Correct Answer)
- C. BCG
- D. Measles
Explanation: **Explanation:** The correct answer is **DPT (Diphtheria, Pertussis, and Tetanus)**. **Why DPT is the correct answer:** Excessive, persistent, and inconsolable crying (defined as crying lasting for 3 hours or more) is a well-documented adverse event following immunization (AEFI) specifically associated with the **whole-cell Pertussis (wP)** component of the DPT vaccine. This reaction typically occurs within 2–24 hours of administration. It is believed to be caused by a combination of local pain at the injection site and a systemic inflammatory response to the pertussis antigens. While distressing to parents, it is usually self-limiting and does not result in long-term neurological sequelae. **Why other options are incorrect:** * **Polio (OPV/IPV):** Generally well-tolerated. OPV is rarely associated with Vaccine-Associated Paralytic Poliomyelitis (VAPP), but not persistent crying. * **BCG:** Common reactions include a local papule, ulceration, and scarring at the site. Systemic reactions like excessive crying are not characteristic. * **Measles:** Common side effects include fever and a mild rash occurring 5–12 days after vaccination, rather than immediate inconsolable crying. **High-Yield Clinical Pearls for NEET-PG:** * **Acellular Pertussis (aP):** Switching from DTwP to DTaP significantly reduces the incidence of excessive crying and febrile seizures. * **Absolute Contraindication to Pertussis vaccine:** Encephalopathy within 7 days of a previous dose. * **HHE (Hypotonic Hyporesponsive Episode):** Another specific AEFI of DPT characterized by sudden loss of muscle tone and pallor; it is also linked to the pertussis component. * **Management:** Paracetamol can be used to manage pain and fever, but persistent crying is not a contraindication to subsequent doses.
Question 9: Which of the following is NOT a criterion for Juvenile Rheumatoid Arthritis?
- A. Age greater than 16 years (Correct Answer)
- B. Arthritis duration greater than 3 weeks
- C. Arthritis duration greater than 6 months
- D. One or more joint involvement
Explanation: **Explanation:** Juvenile Idiopathic Arthritis (JIA), formerly known as Juvenile Rheumatoid Arthritis (JRA), is defined by a specific set of clinical criteria designed to distinguish it from adult inflammatory arthritides. **Why Option A is the correct answer:** The fundamental definition of JIA requires the **onset of symptoms before the age of 16 years**. Therefore, "Age greater than 16 years" is an exclusion criterion and does not fit the diagnostic framework. If the disease starts after age 16, it is classified under adult rheumatoid arthritis or other adult-onset connective tissue disorders. **Analysis of other options:** * **Option B & C (Duration):** To diagnose JIA, arthritis must persist for a minimum of **6 weeks**. While Option B (3 weeks) is technically incorrect in duration, and Option C (6 months) is longer than required, in the context of NEET-PG questions regarding "NOT a criterion," the age limit (Option A) is the absolute defining boundary. *Note: Standard criteria require ≥6 weeks; Option B is often used as a distractor in older question formats.* * **Option D (Joint Involvement):** JIA is characterized by the presence of objective arthritis (swelling or limitation of motion with pain) in **one or more joints**. This is a core requirement for the diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Subtypes:** The most common subtype is **Oligoarthritis** (involving ≤4 joints), which carries a high risk of **asymptomatic chronic anterior uveitis** (requires regular slit-lamp exams). * **Systemic JIA (Still’s Disease):** Characterized by daily "quotidian" fevers, evanescent salmon-pink rashes, and hepatosplenomegaly. * **Markers:** Rheumatoid Factor (RF) is usually negative in children (only positive in ~10-15% of cases, typically older girls). ANA positivity is a strong risk factor for uveitis.
Question 10: A child presents with a constellation of findings including fever, disabling arthritis, rash, and blindness. What is the MOST likely diagnosis?
- A. Rheumatic fever
- B. Lyme disease
- C. Juvenile rheumatoid arthritis (Correct Answer)
- D. Henoch-Schoenlein vasculitis
Explanation: **Explanation:** The correct answer is **Juvenile Rheumatoid Arthritis (JRA)**, now more commonly referred to as **Juvenile Idiopathic Arthritis (JIA)**. The clinical triad of **fever, arthritis, and rash** is characteristic of Systemic-onset JIA (Still’s Disease). However, the inclusion of **blindness** is the diagnostic "clue" pointing toward JIA. Chronic non-granulomatous **anterior uveitis (iridocyclitis)** is a classic extra-articular manifestation of JIA, particularly the oligoarticular subtype. If left untreated, it leads to cataracts, glaucoma, and permanent blindness. Since uveitis is often asymptomatic in children, regular slit-lamp examinations are mandatory. **Why the other options are incorrect:** * **Rheumatic Fever:** While it presents with fever and migratory polyarthritis, it typically involves the heart (carditis) and skin (erythema marginatum). It does **not** cause uveitis or blindness. * **Lyme Disease:** Can cause fever, rash (erythema chronicum migrans), and arthritis, but the arthritis is usually episodic and involves large joints (like the knee). Blindness is not a standard feature. * **Henoch-Schönlein Purpura (HSP):** This is a small-vessel vasculitis characterized by a palpable purpuric rash (usually on the lower limbs), abdominal pain, and arthritis. It involves the kidneys but does not cause blindness. **NEET-PG High-Yield Pearls:** * **Uveitis Risk:** Highest in girls with **Oligoarticular JIA** who are **ANA positive**. * **Still’s Rash:** Characteristically salmon-pink, evanescent (comes and goes with fever), and non-pruritic. * **Macrophage Activation Syndrome (MAS):** A life-threatening complication specifically associated with Systemic JIA. * **First-line Treatment:** NSAIDs are used initially; Methotrexate is the most common DMARD used for persistent disease.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free