Free Pediatrics mock test

Pediatrics sample questions with answers

10 more original exam-style Pediatrics questions, worked in full. They are not real or recalled exam questions, and none of them is in the mock above or on the bank page, so sit the mock first if you have not.

1. Question 1 · Infectious Diseases, Immunology & Allergy

   A 7-year-old with uncomplicated acute haematogenous osteomyelitis of the distal tibia grows methicillin-susceptible Staphylococcus aureus from blood culture. After 4 days of intravenous cefazolin she is afebrile, walking with less pain, and her CRP has fallen from 120 to 20 mg/L. What is the most appropriate antibiotic plan?

   1. ASwitch to oral flucloxacillin or cefalexin and complete a total course of about 3-4 weeks, guided by clinical and CRP response
   2. BContinue intravenous therapy for a minimum of 6 weeks via a central line
   3. CStop antibiotics now, since defervescence and a falling CRP indicate cure
   4. DChange to oral linezolid for 6 weeks to cover possible methicillin resistance
   Show answer and explanation

   Correct answer: A. Switch to oral flucloxacillin or cefalexin and complete a total course of about 3-4 weeks, guided by clinical and CRP response

   Randomised and observational evidence supports early transition to oral therapy in uncomplicated acute haematogenous osteomyelitis once the child is clinically improving with a falling CRP, with a total duration of roughly 3-4 weeks. Prolonged intravenous therapy adds catheter-related complications without improving outcome, stopping at day 4 risks relapse and chronic osteomyelitis, and linezolid is unnecessary and toxic when the isolate is methicillin-susceptible.

   Reference: Peltola H, Paakkonen M, New England Journal of Medicine (2014); ESPID/PIDS paediatric bone and joint infection guidance (2021)

2. Question 2 · Growth, Development, Adolescent Medicine & Behavioral Pediatrics

   A 4-year-old boy meets full DSM-5 criteria for ADHD with impairment at nursery and at home. What is the recommended first-line treatment?

   1. AImmediate-release methylphenidate titrated to effect
   2. BAtomoxetine once daily
   3. CParent training in behaviour management
   4. DClonidine at bedtime
   Show answer and explanation

   Correct answer: C. Parent training in behaviour management

   For preschool children aged 4 to 5 years, evidence-based parent training in behaviour management (with classroom behavioural intervention where available) is first-line, and methylphenidate is added only if behavioural therapy fails and impairment remains moderate to severe. Preschoolers have higher rates of stimulant adverse effects and a greater placebo/behavioural response. Atomoxetine and alpha-2 agonists are second-line options in older children and are not first-line at this age.

   Reference: Wolraich ML et al., AAP Clinical Practice Guideline for ADHD (Pediatrics, 2019); NICE NG87 Attention Deficit Hyperactivity Disorder (2018, updated 2019)

3. Question 3 · Gastroenterology, Hepatology & Nutrition

   Seventy-two hours after nutritional rehabilitation is started in a severely malnourished 3-year-old, he develops new tachycardia, oedema, muscle weakness and confusion. Which biochemical abnormality is most characteristic of the complication that has occurred?

   1. AHypophosphataemia
   2. BHypercalcaemia
   3. CHypernatraemia
   4. DMetabolic alkalosis with hyperchloraemia
   Show answer and explanation

   Correct answer: A. Hypophosphataemia

   Refeeding syndrome follows the insulin surge that accompanies carbohydrate reintroduction, driving phosphate, potassium and magnesium intracellularly; hypophosphataemia is the hallmark and causes cardiac failure, rhabdomyolysis, respiratory muscle weakness and encephalopathy. Prevention requires slow calorie escalation, thiamine supplementation and close electrolyte monitoring. Hypercalcaemia, hypernatraemia and hyperchloraemic alkalosis are not features of refeeding syndrome.

   Reference: WHO Management of Severe Acute Malnutrition; NICE CG32 Nutrition Support in Adults (refeeding criteria applied in paediatric practice); ASPEN Consensus on Refeeding Syndrome, 2020

4. Question 4 · Cardiovascular Medicine

   A 12-year-old girl has had two episodes of syncope, one after her alarm clock woke her suddenly and one during an argument. Her ECG in sinus rhythm at 75/min shows a QT interval of 480 ms, giving a corrected QT of 490 ms by the Bazett formula, with notched T waves. Examination and echocardiogram are normal. Which management plan is most appropriate?

   1. AStart a beta-blocker, avoid QT-prolonging drugs and abrupt auditory stimuli, screen first-degree relatives and restrict competitive sport pending specialist review
   2. BReassure and repeat the ECG in one year with no restrictions
   3. CStart phenytoin for presumed seizures
   4. DInsert a permanent pacemaker as first-line therapy
   Show answer and explanation

   Correct answer: A. Start a beta-blocker, avoid QT-prolonging drugs and abrupt auditory stimuli, screen first-degree relatives and restrict competitive sport pending specialist review

   A QTc of 490 ms with notched T waves and syncope triggered by sudden auditory stimuli and emotion indicates long QT syndrome (typically LQT2), and first-line management is beta-blockade with avoidance of QT-prolonging medications and specific triggers, cascade screening of relatives, and activity restriction pending electrophysiology assessment. Untreated LQTS carries a real risk of torsades de pointes and sudden death, so reassurance is unsafe, and phenytoin treats a diagnosis the story does not support. An ICD, not a pacemaker, is considered for survivors of cardiac arrest or those with syncope despite beta-blockade.

   Reference: AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death, Circulation (2017); HRS/EHRA/APHRS Expert Consensus on Inherited Arrhythmia Syndromes (2013)

5. Question 5 · Nephrology, Urology, Fluids & Electrolytes

   A 7-year-old girl (weight 25 kg) receiving hypotonic intravenous fluids post-operatively has a generalised tonic-clonic seizure. Serum sodium is 118 mmol/L. What is the most appropriate immediate treatment?

   1. AStrict fluid restriction and observation
   2. BIntravenous hypertonic (3%) saline 3-5 mL/kg over 10-20 minutes
   3. CChange the infusion to 0.9% sodium chloride at maintenance rate
   4. DIntravenous furosemide with potassium replacement
   Show answer and explanation

   Correct answer: B. Intravenous hypertonic (3%) saline 3-5 mL/kg over 10-20 minutes

   Acute symptomatic hyponatraemia with seizures is a medical emergency requiring hypertonic 3% saline as a bolus of 3-5 mL/kg to raise serum sodium by roughly 4-6 mmol/L and reverse cerebral oedema. Fluid restriction, isotonic maintenance saline and diuretics all act too slowly for a seizing child, and delay risks herniation; once seizures stop, the subsequent correction must be limited to avoid osmotic demyelination.

   Reference: Nelson Textbook of Pediatrics, 22nd edition (2024); Moritz ML & Ayus JC, Pediatric Nephrology 2010 (management of acute symptomatic hyponatraemia)

6. Question 6 · Professionalism, Ethics, Patient Safety, Preventive & Community Pediatrics

   A pediatric department wishes to run a retrospective chart review of 400 children admitted with bronchiolitis over five years, extracting only de-identified clinical and outcome data. No patient contact is planned and no identifiers will leave the institution. Regarding institutional review board (IRB/research ethics committee) involvement, which statement is most accurate?

   1. AThe project is audit rather than research, so no IRB submission of any kind is needed
   2. BThe project must be submitted to the IRB, which may grant exemption or expedited review and may waive individual consent
   3. CThe project requires full board review with written consent obtained from every parent before data extraction
   4. DIRB approval is required only if the investigators intend to publish the findings in a journal
   Show answer and explanation

   Correct answer: B. The project must be submitted to the IRB, which may grant exemption or expedited review and may waive individual consent

   A systematic retrospective study intended to produce generalisable knowledge is research, so it must be submitted to the IRB; the IRB - not the investigator - determines whether it qualifies for exemption or expedited review and whether the consent requirement can be waived (minimal risk, impracticable to obtain consent, no adverse effect on rights and welfare). Option A lets the investigator self-certify the project as non-research, which is not permitted; option C imposes a standard that would make most minimal-risk records research impossible and ignores the waiver provisions; option D wrongly ties ethical oversight to publication intent rather than to the nature of the activity.

   Reference: Council for International Organizations of Medical Sciences (CIOMS) International Ethical Guidelines for Health-related Research Involving Humans, Guidelines 10 and 12 (2016); US 45 CFR 46.104 and 46.116(f); WMA Declaration of Helsinki (2013, amended 2024)

7. Question 7 · Acute Care, Pediatric Emergency & Critical Care (PICU)

   Six hours into treatment for diabetic ketoacidosis, an 8-year-old develops a severe headache, becomes drowsy and incontinent, and his heart rate falls from 120 to 68/min while blood pressure rises. The biochemical parameters are improving. What is the most appropriate immediate management?

   1. AIncrease the rate of intravenous fluid to treat presumed hypovolaemia
   2. BObtain an urgent CT of the head before any therapeutic intervention
   3. CReduce the fluid rate by about one third and give hypertonic 3% saline (or mannitol) immediately
   4. DStop the insulin infusion and give a bolus of 10% dextrose
   Show answer and explanation

   Correct answer: C. Reduce the fluid rate by about one third and give hypertonic 3% saline (or mannitol) immediately

   Headache with deteriorating consciousness, bradycardia, hypertension and incontinence during DKA treatment is diagnostic of cerebral oedema, and treatment with hyperosmolar therapy plus a reduction in fluid rate must be given immediately on clinical grounds. Neuroimaging must never delay treatment and is performed only after the child is stabilised. Increasing fluids would worsen cerebral oedema, and the picture is not one of hypoglycaemia, so stopping insulin and giving dextrose does not address the emergency.

   Reference: ISPAD Clinical Practice Consensus Guidelines 2022: Diabetic Ketoacidosis and Hyperglycaemic Hyperosmolar State

8. Question 8 · Neonatology & Perinatal Medicine (NICU)

   A term infant of consanguineous parents has seizures from the first hours of life that continue despite two loading doses of phenobarbital and a load of levetiracetam. There was no perinatal asphyxia, glucose and electrolytes are normal, cranial imaging and CSF are unremarkable, and blood and CSF cultures are negative. What is the most appropriate next step?

   1. AStart a ketogenic diet
   2. BGive a further phenobarbital load to a level above 60 mg/L
   3. CStart empirical aciclovir and repeat the lumbar puncture
   4. DGive intravenous pyridoxine with continuous EEG monitoring
   Show answer and explanation

   Correct answer: D. Give intravenous pyridoxine with continuous EEG monitoring

   Refractory neonatal seizures with no identifiable cause, particularly in a consanguineous family, should prompt a trial of intravenous pyridoxine (typically 100 mg) under continuous EEG and cardiorespiratory monitoring, since pyridoxine-dependent epilepsy responds dramatically and is treatable, with pyridoxal phosphate and folinic acid trials to follow if there is no response. Escalating phenobarbital to toxic levels risks respiratory and cardiovascular depression without addressing the cause. A ketogenic diet is not a first manoeuvre in the acute neonatal period, and empirical aciclovir would already have been considered but is unsupported once herpes PCR and CSF findings are unremarkable.

   Reference: Volpe's Neurology of the Newborn, 6th edition, 2018; Nelson Textbook of Pediatrics, 22nd edition, 2024

9. Question 9 · Respiratory Medicine

   A 15-year-old athlete reports noisy, difficult inspiration during intense exercise with throat tightness that resolves within minutes of stopping; inhaled salbutamol has not helped. Spirometry between episodes shows a flattened (truncated) inspiratory limb of the flow-volume loop with a normal expiratory limb. What does this pattern indicate?

   1. AVariable extrathoracic airway obstruction, such as inducible laryngeal obstruction (vocal cord dysfunction)
   2. BVariable intrathoracic obstruction such as tracheomalacia
   3. CFixed obstruction such as a tracheal stenosis
   4. DSmall airway obstruction typical of exercise-induced bronchoconstriction
   Show answer and explanation

   Correct answer: A. Variable extrathoracic airway obstruction, such as inducible laryngeal obstruction (vocal cord dysfunction)

   Selective flattening of the inspiratory limb with a normal expiratory limb signals variable extrathoracic obstruction, and in an adolescent with exertional inspiratory stridor, throat tightness, rapid resolution and no response to bronchodilator the diagnosis is inducible laryngeal obstruction, confirmed by continuous laryngoscopy during exercise. Variable intrathoracic obstruction flattens the expiratory limb, fixed obstruction flattens both limbs, and exercise-induced bronchoconstriction causes a post-exercise fall in FEV1 with an expiratory obstructive pattern that responds to salbutamol.

   Reference: ATS/ERS Technical Standards: Interpretive Strategies for Lung Function Tests (2022); ERS/ELS/ACSM statement on inducible laryngeal obstruction (2017)

10. Question 10 · Endocrinology, Metabolic Disease & Genetics

    A 3-year-old boy had severe neonatal hypotonia with a weak cry and poor suck requiring tube feeding, and he now has relentless hyperphagia with rapid weight gain, small hands and feet, cryptorchidism with a small penis, and developmental delay. Methylation analysis of the 15q11-q13 region is abnormal. Which mechanism accounts for the majority of cases of this condition?

    1. AMaternal uniparental disomy of chromosome 15
    2. BAn imprinting centre defect
    3. CA pathogenic variant in UBE3A on the maternally inherited chromosome
    4. DA deletion of the paternally inherited 15q11-q13 region
    Show answer and explanation

    Correct answer: D. A deletion of the paternally inherited 15q11-q13 region

    This is Prader-Willi syndrome, and about 65-75% of cases result from a de novo deletion of the paternally inherited 15q11-q13 region, with maternal uniparental disomy accounting for roughly 20-30% and imprinting defects for only 1-3%. Methylation testing detects all three mechanisms, so follow-up testing is needed to define the mechanism and refine recurrence risk. A maternal UBE3A variant causes Angelman syndrome, a clinically distinct disorder with severe speech impairment, ataxia, a happy demeanour and seizures rather than hyperphagic obesity.

    Reference: Prader-Willi Syndrome, GeneReviews (updated 2023); Nelson Textbook of Pediatrics, 22nd edition (2024)