20 High-Yield Pediatrics MCQs with Answers and Explanations

Welcome to Medical Gait. Test your pediatric knowledge with these 20 high-yield MCQs covering congenital heart disease, endocrinology, neonatology, developmental milestones, and nephrology. Each question includes an answer, explanation, exam pearl, and medical resource for further reading.

Instructions: Attempt each question before clicking Show Answer & Explanation. Review the exam pearl and recommended resource to reinforce your knowledge.

Section 1: Congenital and Acquired Heart Disease

Question 1: Acute Rheumatic Fever

A child with acute rheumatic fever develops involuntary, purposeless movements. What is this manifestation called?

1. Sydenham chorea
2. Athetosis due to kernicterus
3. Intention tremor
4. Spastic paralysis

Correct Answer: A. Sydenham chorea

Sydenham chorea is a neurological manifestation of acute rheumatic fever. It causes involuntary, irregular, non-rhythmic movements and may be associated with emotional and behavioural changes.

Exam Pearl: Sydenham chorea is a major manifestation of acute rheumatic fever.

Further Reading: CDC: Acute Rheumatic Fever

Question 2: Patent Ductus Arteriosus

A premature infant has a continuous heart murmur and bounding peripheral pulses. What is the most likely diagnosis?

1. Patent ductus arteriosus
2. Pulmonary stenosis
3. Aortic stenosis
4. Atrial septal defect

Correct Answer: A. Patent ductus arteriosus (PDA)

PDA results from failure of the ductus arteriosus to close after birth. A continuous, machinery-like murmur is characteristic. A significant left-to-right shunt may cause bounding pulses and wide pulse pressure.

Exam Pearl: Prematurity + continuous murmur + bounding pulses = think PDA.

Further Reading: CDC: Congenital Heart Defects

Question 3: Kawasaki Disease

Which serious complication is classically associated with Kawasaki disease?

1. Coronary artery aneurysm
2. Rheumatic mitral stenosis
3. Aortic coarctation
4. Tetralogy of Fallot

Correct Answer: A. Coronary artery aneurysm

Kawasaki disease is a systemic vasculitis affecting medium-sized arteries. Coronary artery inflammation may lead to dilatation and aneurysm formation.

Exam Pearl: Early recognition and treatment help reduce the risk of coronary complications.

Further Reading: Canadian Paediatric Society: Kawasaki Disease

Question 4: Transposition of the Great Arteries

A newborn develops profound cyanosis shortly after birth. Which congenital heart defect is a classic cause?

1. Transposition of the great arteries
2. Small ventricular septal defect
3. Mild pulmonary stenosis
4. Small atrial septal defect

Correct Answer: A. Transposition of the great arteries

In this condition, the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. The systemic and pulmonary circulations run in parallel rather than in series.

Survival depends on mixing between the circulations through connections such as an atrial septal defect, ventricular septal defect, or patent ductus arteriosus.

Exam Pearl: Severe cyanosis soon after birth requires urgent assessment for critical congenital heart disease.

Further Reading: CDC: D-Transposition of the Great Arteries

Question 5: Coarctation of the Aorta

A neonate presents with poor feeding, respiratory distress, weak femoral pulses, and heart failure. Which diagnosis should be suspected?

1. Coarctation of the aorta
2. Uncomplicated atrial septal defect
3. Mild mitral valve prolapse
4. Small patent foramen ovale

Correct Answer: A. Coarctation of the aorta

Coarctation is a narrowing of the aorta. Severe neonatal disease can cause poor systemic perfusion and heart failure, particularly when the ductus arteriosus closes.

Clinical Pearl: Compare upper- and lower-limb pulses and blood pressure.

Further Reading: CDC: Congenital Heart Defects

Question 6: Diastolic Murmur

A child is found to have a diastolic heart murmur. What is the most appropriate interpretation?

1. It warrants evaluation for pathological valve disease
2. It is always an innocent murmur
3. It confirms an atrial septal defect
4. It excludes structural heart disease

Correct Answer: A. It warrants evaluation for pathological valve disease

Diastolic murmurs are generally considered pathological and require clinical assessment. Further investigations, including echocardiography, may be indicated.

Exam Pearl: A diastolic murmur should not automatically be labelled innocent.

Further Reading: Merck Manual Professional Edition

Section 2: Paediatric Endocrinology

Question 7: Congenital Hypothyroidism

Which finding may occur in an infant with congenital hypothyroidism?

1. Prolonged neonatal jaundice
2. Persistent high fever
3. Exophthalmos
4. Marked hyperactivity

Correct Answer: A. Prolonged neonatal jaundice

Other features may include lethargy, constipation, poor feeding, hypotonia, macroglossia, and umbilical hernia. Some affected infants have few obvious signs at birth.

Early diagnosis and thyroid hormone replacement are essential for normal brain development and growth.

Exam Pearl: Newborn screening is important because early clinical signs may be subtle.

Further Reading: American Thyroid Association: Congenital Hypothyroidism

Question 8: Coeliac Disease

A child presents with chronic diarrhoea, poor growth, and iron-deficiency anaemia. Which diagnosis should be considered?

1. Coeliac disease
2. Acute appendicitis
3. Pyloric stenosis
4. Intussusception

Correct Answer: A. Coeliac disease

Coeliac disease is an immune-mediated disorder triggered by gluten in genetically susceptible individuals. Damage to the small intestinal mucosa may cause malabsorption, diarrhoea, poor growth, and iron-deficiency anaemia.

Exam Pearl: Consider coeliac disease in unexplained growth failure or persistent iron-deficiency anaemia.

Further Reading: NIDDK: Coeliac Disease

Question 9: Congenital Adrenal Hyperplasia

Which enzyme deficiency is the most common cause of classic congenital adrenal hyperplasia?

1. 21-hydroxylase
2. 11-beta-hydroxylase
3. 17-alpha-hydroxylase
4. Aromatase

Correct Answer: A. 21-hydroxylase deficiency

This deficiency impairs cortisol synthesis and may reduce aldosterone production, increasing ACTH stimulation and androgen production.

The salt-wasting form may cause dehydration, hyponatraemia, hyperkalaemia, and circulatory collapse.

Exam Pearl: A newborn with vomiting, dehydration, hyponatraemia, and hyperkalaemia may have a life-threatening adrenal crisis.

Further Reading: NIDDK: Congenital Adrenal Hyperplasia

Question 10: Childhood Hypothyroidism

A school-aged child has fatigue, constipation, cold intolerance, and slowing of growth. Which disorder best explains these features?

1. Hypothyroidism
2. Hyperthyroidism
3. Diabetes insipidus
4. Phaeochromocytoma

Correct Answer: A. Hypothyroidism

Thyroid hormone deficiency slows metabolic activity and may cause fatigue, constipation, cold intolerance, and reduced linear growth.

Exam Pearl: Poor growth with constipation and cold intolerance should raise suspicion of hypothyroidism.

Further Reading: American Thyroid Association

Question 11: Androgen Insensitivity Syndrome

A 46,XY adolescent has a female external appearance, undescended testes, and absent or sparse pubic hair. What is the most likely diagnosis?

1. Androgen insensitivity syndrome
2. Turner syndrome
3. Congenital hypothyroidism
4. Klinefelter syndrome

Correct Answer: A. Androgen insensitivity syndrome

In complete androgen insensitivity syndrome, tissues do not respond normally to androgens. Affected individuals typically have a 46,XY karyotype and female external genitalia, with sparse pubic and axillary hair.

Exam Pearl: Interpret the karyotype alongside the external phenotype and pubertal findings.

Further Reading: NHS: Androgen Insensitivity Syndrome

Question 12: Type 1 Diabetes Mellitus

A child with newly diagnosed type 1 diabetes temporarily requires much less insulin after initial treatment. What is this phase called?

1. Honeymoon phase
2. Permanent remission
3. Diabetes insipidus phase
4. Somogyi phenomenon

Correct Answer: A. Honeymoon phase

This is a temporary period of partial remission after diagnosis and treatment of type 1 diabetes. Residual beta-cell function may reduce insulin requirements.

It does not mean diabetes has been permanently cured. Glucose monitoring and clinical follow-up remain essential.

Exam Pearl: Insulin requirements can fall temporarily after treatment begins.

Further Reading: NIDDK: Diabetes Information

Question 13: Paediatric Diabetic Ketoacidosis

A child with diabetic ketoacidosis is dehydrated and tachycardic. Which initial management principle is most appropriate?

1. Careful isotonic fluid resuscitation with close monitoring
2. Immediate large intravenous insulin bolus
3. Withhold all fluids until ketones disappear
4. Give bicarbonate routinely to every child

Correct Answer: A. Careful isotonic fluid resuscitation with close monitoring

Management includes assessment of circulation, appropriate isotonic fluid therapy, insulin according to a paediatric DKA protocol, electrolyte management, and frequent clinical and biochemical monitoring.

• Do not routinely give an intravenous insulin bolus.
• Monitor potassium and replace it when indicated.
• Bicarbonate is not routinely recommended.
• Monitor neurological status for signs of cerebral injury.

Safety Point: Paediatric DKA is a medical emergency. Follow a current protocol with experienced clinical supervision.

Further Reading: Canadian Paediatric Society: Paediatric DKA

Question 14: Salt-Wasting Congenital Adrenal Hyperplasia

A newborn with congenital adrenal hyperplasia develops vomiting, dehydration, hyponatraemia, and hyperkalaemia. Which mechanism best explains this pattern?

1. Aldosterone deficiency due to 21-hydroxylase deficiency
2. Excess aldosterone secretion
3. Excess thyroid hormone
4. Insulin deficiency alone

Correct Answer: A. Aldosterone deficiency due to 21-hydroxylase deficiency

Reduced aldosterone production causes renal sodium loss and impaired potassium excretion. This may result in hyponatraemia, hyperkalaemia, dehydration, and hypotension.

Exam Pearl: This electrolyte pattern in a newborn can indicate an adrenal crisis requiring urgent medical treatment.

Further Reading: NIDDK: Congenital Adrenal Hyperplasia

Section 3: Neonatology and Development

Question 15: Developmental Milestones

Which developmental skill is commonly expected around 12 months of age?

1. Pulling to stand and cruising
2. Riding a bicycle independently
3. Writing full sentences
4. Hopping repeatedly on one foot

Correct Answer: A. Pulling to stand and cruising

Many infants around this age can pull themselves to stand and move along furniture while holding on. Milestones vary between children.

Exam Pearl: Assess development as a whole rather than relying on a single milestone.

Further Reading: CDC: Developmental Milestones

Question 16: Classification of Prematurity

A baby is born at 35 completed weeks of gestation. How is the infant classified?

1. Late preterm
2. Extremely preterm
3. Very preterm
4. Term

Correct Answer: A. Late preterm

Late-preterm infants are born from 34 weeks through 36 weeks and 6 days of gestation. Term birth begins at 37 completed weeks.

Exam Pearl: A 35-week infant is preterm, not term.

Further Reading: WHO: Preterm Birth

Question 17: Congenital Toxoplasmosis

Which combination is classically associated with congenital toxoplasmosis?

1. Chorioretinitis, hydrocephalus, and intracranial calcifications
2. Cataracts, patent ductus arteriosus, and deafness
3. Microcephaly, periventricular calcifications, and hearing loss
4. Limb hypoplasia and skin scarring

Correct Answer: A. Chorioretinitis, hydrocephalus, and intracranial calcifications

Congenital toxoplasmosis can cause ocular and neurological disease. The classic triad consists of chorioretinitis, hydrocephalus, and intracranial calcifications.

Exam Distinction: Congenital cytomegalovirus is classically associated with periventricular calcifications and sensorineural hearing loss.

Further Reading: NIH: Toxoplasmosis in Children

Question 18: Prevention of Perinatal Hepatitis B

A newborn is delivered by a mother who is HBsAg-positive. Which prophylaxis should be given promptly after birth?

1. Hepatitis B vaccine and hepatitis B immunoglobulin
2. Hepatitis B vaccine only at six months
3. Oral antibiotics for seven days
4. No prophylaxis if the infant appears healthy

Correct Answer: A. Hepatitis B vaccine and hepatitis B immunoglobulin (HBIG)

Infants born to HBsAg-positive mothers should receive hepatitis B vaccine and HBIG promptly after birth at separate injection sites, according to current national guidance.

Exam Pearl: The newborn may appear healthy despite the risk of infection. Timely prophylaxis is essential.

Further Reading: CDC: Perinatal Hepatitis B Prevention

Question 19: Six-Month Developmental Milestones

Which gross motor skill is commonly present by approximately six months of age?

1. Rolling over
2. Walking independently
3. Hopping on one foot
4. Pedalling a tricycle

Correct Answer: A. Rolling over

Rolling over is a common early gross motor milestone. Around this age, infants also develop better head and trunk control and may begin sitting with support.

Exam Pearl: Loss of previously acquired skills warrants prompt developmental assessment.

Further Reading: CDC: Developmental Milestones

Section 4: Paediatric Nephrology

Question 20: Nephrotic Syndrome

A child presents with oedema, heavy proteinuria, hypoalbuminaemia, and hyperlipidaemia. Which diagnosis best fits this presentation?

1. Nephrotic syndrome
2. Nephritic syndrome
3. Acute cystitis
4. Renal stones

Correct Answer: A. Nephrotic syndrome

Nephrotic syndrome is characterized by substantial urinary protein loss, low serum albumin, oedema, and often elevated serum lipids. Children may present with periorbital or generalized oedema.

Nephritic syndrome is more strongly associated with haematuria, hypertension, and reduced renal function, although clinical features can overlap.

Exam Pearl: Proteinuria + hypoalbuminaemia + oedema strongly suggests nephrotic syndrome.

Further Reading: NIDDK: Nephrotic Syndrome in Children

Final Revision: High-Yield Points

• Sydenham chorea: Neurological manifestation of acute rheumatic fever.
• PDA: Continuous murmur; significant shunts may cause bounding pulses.
• Kawasaki disease: Coronary artery aneurysm is a major complication.
• Transposition: Can cause severe neonatal cyanosis.
• Coarctation: Weak femoral pulses and impaired lower-body perfusion.
• Congenital hypothyroidism: Prolonged jaundice and constipation may occur.
• Coeliac disease: Consider with malabsorption, poor growth, and iron-deficiency anaemia.
• 21-hydroxylase deficiency: The commonest cause of classic congenital adrenal hyperplasia.
• Paediatric DKA: Requires monitored fluids, insulin, and electrolyte management.
• Congenital toxoplasmosis: Chorioretinitis, hydrocephalus, and intracranial calcifications.
• Perinatal hepatitis B: Prompt newborn prophylaxis is essential.
• Nephrotic syndrome: Proteinuria, hypoalbuminaemia, and oedema.

Medical Disclaimer

This article is intended for medical education and examination revision. It does not replace clinical assessment, local clinical guidelines, or specialist advice. Management recommendations may vary according to the patient's condition and applicable national protocols.

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