# MCCQE Part I Paediatrics Questions: 10 Free Practice MCQs

> 10 free MCCQE Part I paediatrics questions with answers and explanations, from a bank of 200 paediatrics questions. Try them now, no sign up.

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Last updated: 2026-10-29

Ten MCCQE Part I-style paediatrics questions with the answer and the reasoning behind it. They come from the CA.med bank, which has 200 paediatrics questions and many more across every topic.

1. 1 / 10  
A 2-year-old boy is diagnosed with Kawasaki disease on day 6 of fever. Echocardiography has been arranged, and treatment is being planned with the family.  
Which treatment reduces the risk of coronary artery aneurysms in this child?  
Show answer

**Answer: D.** A single dose of intravenous immunoglobulin 2 g/kg

**Why:** One dose of intravenous immunoglobulin at 2 g/kg reduces the risk of coronary artery aneurysms to under 5% when provided within the first 10 days of fever, and treatment is still given after day 10 when fever and inflammation persist. Acetylsalicylic acid is added for its antiplatelet effect, and serial echocardiography is needed because aneurysms may develop up to 4 to 6 weeks after onset.

  * **A.** Antibiotics are not the treatment for this systemic vasculitis, although a coexisting infection should still be treated.
  * **B.** Acetylsalicylic acid is used for its antiplatelet effect, but it does not reduce aneurysm formation on its own.
  * **C.** Evidence for corticosteroids and coronary outcomes is conflicting, and steroids are used with rheumatology input for intensification or after resistance to immunoglobulin.  
Sources: Canadian Paediatric Society. Kawasaki disease: Practical guidance on diagnosis and management. Practice point, 2026.
2. 2 / 10  
A newborn is noted at delivery to have upward-slanting palpebral fissures, a flat facial profile, small ears, a single palmar crease, sandal-gap deformity of the toes, and generalised hypotonia. The mother is 36 years old. Amniocentesis was declined during pregnancy.  
Which congenital heart defect is most commonly associated with this syndrome?  
Show answer

**Answer: B.** Atrioventricular septal defect (AVSD)

**Why:** Down syndrome (trisomy 21) is the most common chromosomal disorder (1:700 live births, rising with advanced maternal age). Features: upslanting palpebral fissures, epicanthal folds, flat nasal bridge, protruding tongue, single palmar crease, fifth finger clinodactyly, sandal gap, Brushfield spots. Congenital heart disease in 40–50%: AVSD most common, followed by VSD, ASD, PDA, TOF. Mandatory workup: echocardiogram, hearing assessment, thyroid function, ophthalmology. Chromosomal analysis confirms diagnosis. Complications: Hirschsprung disease, leukaemia (AML/ALL), Alzheimer disease (early onset), atlantoaxial instability, obstructive sleep apnoea.

  * **A.** Tetralogy of Fallot occurs in \~10% of Down syndrome patients with CHD but is not the most common lesion. AVSD is the classic association.
  * **C.** TGA is not a characteristic lesion of Down syndrome. It is associated with diabetic embryopathy and laterality defects but not trisomy 21.
  * **D.** HLHS is not specifically associated with Down syndrome. It is associated with Turner syndrome and various genetic conditions, but AVSD is the classic cardiac defect of trisomy 21.  
Sources: CPS Position Statement: Health Supervision for Children with Down Syndrome (2018); American Academy of Pediatrics Down Syndrome Guidelines
3. 3 / 10  
A 12-year-old boy with ADHD presents with new restlessness, palpitations and worry. He began a decongestant for a cold last week and drinks two colas containing caffeine each day.  
Which step belongs in the assessment of his new symptoms?  
Show answer

**Answer: C.** Review medications and dietary stimulants that can mimic anxiety

**Why:** Sympathomimetic exposures such as stimulant medication, caffeine, decongestants and bronchodilators can produce effects that mimic anxiety, so medication and dietary histories should be obtained before diagnosing an anxiety disorder. In older children and adolescents, nicotine, amphetamines, alcohol or cannabis may also be used in an attempt to reduce anxiety symptoms.

  * **A.** Diagnosing an anxiety disorder before excluding an obvious mimic risks labelling a stimulant effect as a psychiatric disorder.
  * **B.** Beginning an antidepressant before clarifying the cause of his symptoms would be premature and could complicate the picture further.
  * **D.** Reassurance alone would miss the exposures that may explain his restlessness and palpitations and would leave the question unanswered.  
Sources: Anxiety in children and youth: Part 1\. Diagnosis. Canadian Paediatric Society, 2022
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5. 4 / 10  
A 6-year-old girl presents with recurrent episodes of coughing and wheeze, predominantly at night and with exercise. She has 3–4 symptomatic days per week and wakes once weekly. Spirometry shows FEV₁/FVC 0.72 with a 15% improvement post-bronchodilator. SpO₂ 97% at baseline.  
According to GINA/CPS guidelines, what is the appropriate initial controller therapy for this child's asthma severity?  
Show answer

**Answer: B.** Low-dose inhaled corticosteroid (ICS) daily (e.g., fluticasone 50 mcg BID or budesonide 200 mcg BID) plus salbutamol as reliever

**Why:** GINA/CPS asthma classification (≥5 years): Intermittent (symptoms ≤2 days/week, no nocturnal, FEV₁ ≥80%) → Step 1 (SABA as needed); Mild persistent (>2 days/week, >2 nights/month) → Step 2 (low-dose ICS); Moderate persistent (daily symptoms, nightly symptoms >1/week) → Step 3 (medium ICS or low ICS + LABA); Severe persistent → Step 4–5\. ICS are first-line controllers for all persistent asthma. Spacer use is essential for children <8 years using pMDI. Asthma action plan should be provided to all patients.

  * **A.** SABA-only therapy is appropriate for mild intermittent asthma (symptoms ≤2 days/week, no nocturnal symptoms, no interference with activity). This child's symptom frequency exceeds this threshold and requires a controller.
  * **C.** Systemic corticosteroids are reserved for acute exacerbations, not initial controller therapy for chronic asthma. Inhaled corticosteroids are the preferred long-term controller.
  * **D.** Montelukast is an alternative first-line controller (GINA Step 2) when ICS is not tolerated or for exercise-induced asthma. ICS is preferred as first-line due to superior evidence for exacerbation reduction.  
Sources: GINA Report 2023; CPS Position Statement: Asthma in Children
6. 5 / 10  
A 2-year-old boy has iron deficiency anaemia attributed to excessive cow milk intake and a diet low in iron-rich foods. His haemoglobin is 92 g/L with microcytosis and a low ferritin. His parents are ready to start treatment and ask how it should be given and how long it should continue.  
What is the most appropriate treatment plan?  
Show answer

**Answer: B.** Oral elemental iron 2 to 6 mg/kg/day in divided doses for at least 3 months, then reassess iron status

**Why:** Iron deficiency anaemia caused by insufficient intake in infants and toddlers is treated with oral elemental iron 2 to 6 mg/kg/day in divided doses, and absorption improves when iron is taken with a source of vitamin C. Supplements should continue for a minimum of 3 months, after which iron status including complete blood count and serum ferritin is reassessed. The BC guideline adds that anaemia should correct in 2 to 4 months and that oral iron should then continue for 4 to 6 months after correction to replenish iron stores.

  * **A.** This dose is below the therapeutic range recommended for treating iron deficiency anaemia in infants and toddlers.
  * **C.** Transfusion is very rarely required in children because anaemia develops gradually and the response to oral iron is prompt, being reserved for severe anaemia with haemodynamic compromise.
  * **D.** Oral iron is first-line, and intravenous iron is considered when there is inadequate response to oral therapy, intolerance, or ongoing blood loss.  
Sources: Canadian Paediatric Society. Iron requirements in the first 2 years of life (2019, reaffirmed 2025); Government of British Columbia (BC Guidelines and Protocols Advisory Committee). Iron Deficiency: Diagnosis and Management (2019)
7. 6 / 10  
A 9-year-old boy presents to the emergency department with a 1-week history of polyuria, polydipsia, and weight loss, and a 1-day history of nausea and vomiting. He appears ill. Kussmaul breathing is noted. Labs: glucose 28 mmol/L, pH 7.18, HCO₃ 8 mmol/L, anion gap 24, serum ketones positive, Na 128 mmol/L.  
What is the most critical risk during fluid resuscitation of DKA in a child?  
Show answer

**Answer: C.** Cerebral oedema due to rapid fluid administration and osmolarity shifts

**Why:** Paediatric DKA management (ISPAD 2022): (1) Resuscitation: 10 mL/kg normal saline bolus only if haemodynamically compromised; (2) Rehydration: deficit + maintenance over 24–48 hours (NOT rapid) — use 0.9% NaCl for first 4–6 hours then 0.45% NaCl with dextrose when glucose <14 mmol/L; (3) Insulin: 0.05–0.1 units/kg/hr IV drip AFTER 1–2h of fluids (not before); (4) Potassium: add KCl once urine output established; (5) Cerebral oedema: signs include headache, restlessness, declining GOS, bradycardia — treat with 0.5–1 g/kg mannitol IV immediately.

  * **A.** Hypokalaemia is a real risk in DKA (potassium shifts back into cells with insulin treatment), requiring potassium replacement. However, cerebral oedema is the most critical paediatric-specific risk.
  * **B.** Hypoglycaemia can occur if insulin is not reduced when glucose approaches target range, but it is not the most critical or paediatric-specific complication during fluid resuscitation.
  * **D.** ARDS from crystalloid is not a primary concern in paediatric DKA. The ISPAD-recommended 24–48-hour rehydration approach protects against volume overload while restoring fluid deficit slowly.  
Sources: ISPAD Clinical Practice Consensus Guidelines 2022: DKA and Hyperglycaemic Hyperosmolar State; CPS Paediatric DKA Guidelines
8. 7 / 10  
A 7-year-old boy with known sickle cell disease (HbSS) presents with fever (38.9°C), chest pain, progressive dyspnoea, and cough over 24 hours. Chest X-ray shows a new right lower lobe infiltrate. SpO₂ 91% on room air. WBC 18 × 10⁹/L, Hb 60 g/L (baseline 80 g/L).  
What is the most appropriate management for this presentation?  
Show answer

**Answer: B.** Oxygen, IV fluids, broad-spectrum antibiotics (ceftriaxone + azithromycin), analgesia, and simple blood transfusion

**Why:** Acute chest syndrome (ACS) is the leading cause of death in sickle cell disease, occurring in \~50% of HbSS patients during their lifetime. Definition: new radiographic pulmonary infiltrate + fever or respiratory symptoms. Causes: vaso-occlusion, fat embolism (from infarcted bone marrow), infection (S. pneumoniae, Mycoplasma, Chlamydophila), and hypoventilation. Management: (1) O₂ supplementation; (2) IV antibiotics: ceftriaxone + azithromycin (covers typical and atypical); (3) analgesia; (4) incentive spirometry (prevents atelectasis); (5) simple transfusion for significant anaemia; (6) exchange transfusion for severe disease. Hydroxyurea reduces ACS frequency (increases HbF).

  * **A.** Penicillin alone does not cover atypical organisms (Mycoplasma, Chlamydophila) which cause ACS. Transfusion is NOT contraindicated — it is indicated for significant drops in haemoglobin or SpO₂ <95%.
  * **C.** Exchange transfusion (reducing HbS% to <30%) is reserved for severe ACS (SpO₂ <90% despite supplemental O₂, rapid progression, multilobar disease). Simple transfusion is appropriate first-line when Hb drops significantly.
  * **D.** Aggressive fluid bolus in ACS can precipitate pulmonary oedema and worsen respiratory status. IV fluids should be given at maintenance rates, not bolus, unless the patient is significantly dehydrated and haemodynamically unstable.  
Sources: CPS Position Statement: Sickle Cell Disease — Management of Acute Chest Syndrome; NHLBI Sickle Cell Disease Expert Panel Report
9. 8 / 10  
A 3-year-old boy has 1 day of mild right ear pain and a temperature of 38.1 C. He is alert, drinking well and comfortable after acetaminophen. His tympanic membrane is mildly bulging, and his parents are able to return the next day if needed.  
What is the most appropriate management according to the CPS position statement?  
Show answer

**Answer: D.** Watchful waiting for 24 to 48 hours with analgesia and assured reassessment

**Why:** Children who have a mild or moderately bulging tympanic membrane and who are mildly ill, alert, responding to antipyretics, have a low-grade fever below 39.0 C and mild otalgia can safely be managed with watchful waiting for 24 to 48 hours, provided that analgesia is advised and follow-up is arranged. Immediate antibiotics are reserved for children who are highly febrile, severely unwell or have been significantly ill for 48 hours.

  * **A.** Immediate antibiotics are advised for children who are highly febrile, moderately to severely ill, or have been significantly ill for 48 hours, which does not describe this child.
  * **B.** Parenteral ceftriaxone is reserved for children who cannot take oral drugs or who have failed oral therapy, not for mild illness.
  * **C.** Surgical referral is not part of the acute management of a mild first episode of acute otitis media.  
Sources: Canadian Paediatric Society. Management of acute otitis media in children six months of age and older. Paediatr Child Health 2016;21(1):39-44\. Reaffirmed 2024.
10. 9 / 10  
An asymptomatic 6-year-old has a continuous 'machinery' murmur heard at the upper left sternal edge.  
What is the likely diagnosis?  
Show answer

**Answer: A.** Patent Ductus Arteriosus

**Why:** Patent Ductus Arteriosus (PDA) produces a classic continuous 'machinery' murmur heard loudest at the upper left sternal border because aortic pressure exceeds pulmonary arterial pressure throughout both systole and diastole. In contrast, VSD presents with a pansystolic murmur, ASD with a fixed split S2 and ejection systolic murmur, and innocent murmurs change with posture.

  * **B.** Pan-systolic murmur.
  * **C.** Fixed split S2, ejection systolic murmur.
  * **D.** Usually systolic and changing with position.  
Sources: Oxford Handbook of Paediatrics
11. 10 / 10  
A 7-year-old boy presents 2 weeks after a streptococcal sore throat with a purpuric rash on the lower limbs and buttocks, bilateral ankle arthritis, and colicky abdominal pain. Urinalysis shows 2+ protein and 2+ blood. Blood pressure is 118/78 mmHg. Platelets are 280 × 10⁹/L (normal). Anti-streptolysin O is positive.  
What is the diagnosis and the most important complication to monitor?  
Show answer

**Answer: D.** IgA vasculitis (Henoch-Schönlein purpura); nephritis (renal disease)

**Why:** IgA vasculitis (HSP) is the most common systemic vasculitis in children (peak age 4–7 years). Diagnostic criteria: palpable purpura in a dependent distribution (non-thrombocytopenic) + ≥1 of: abdominal pain, arthritis/arthralgia, renal involvement (haematuria/proteinuria), or biopsy showing IgA deposits. Renal involvement (HSPN) occurs in \~30–50%, ranging from microscopic haematuria to RPGN. Management: (1) NSAIDs for arthralgia; (2) corticosteroids for severe abdominal pain (not proven to prevent nephritis); (3) serial urinalysis and BP monitoring for 6–12 months; (4) nephrology referral for nephritic/nephrotic syndrome or significant proteinuria.

  * **A.** ITP is characterised by isolated thrombocytopenia (<100 × 10⁹/L) causing mucocutaneous bleeding. Normal platelets rule out ITP. HSP/IgA vasculitis is the correct diagnosis.
  * **B.** Meningococcal purpura is typically rapidly progressive with fever, haemodynamic compromise, and a unwell appearance. This child has a subacute presentation with arthritis and abdominal pain post-streptococcal infection, which is consistent with IgA vasculitis.
  * **C.** SLE can cause purpura and nephritis but typically occurs in older adolescent females with other features (malar rash, ANA positive, cytopenias). The post-streptococcal trigger and classic HSP triad support IgA vasculitis.  
Sources: CPS Position Statement: IgA Vasculitis (HSP) (2020)

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