PLAB PLAB Pediatrics & Child Health 2 — Questions and Answers
Question 1: A 4-year-old child presents with a widespread purpuric rash, arthritis, colicky abdominal pain, and haematuria. What is the most likely diagnosis?
- Meningococcal septicemia
- Henoch-Schönlein Purpura (IgA vasculitis) (Correct answer)
- Idiopathic thrombocytopenic purpura
- Systemic lupus erythematosus
Correct answer: Henoch-Schönlein Purpura (IgA vasculitis)
Henoch-Schönlein Purpura (IgA vasculitis) is the most common childhood vasculitis, characterized by the tetrad of palpable purpura (predominantly lower limbs/buttocks), arthritis, colicky abdominal pain, and renal involvement (haematuria).
Question 2: What is the hallmark ECG finding in complete atrioventricular (AV) block in a neonate?
- Short PR interval with delta wave
- Complete dissociation between P waves and QRS complexes (Correct answer)
- Prolonged QT interval
- ST elevation in V1–V3
Correct answer: Complete dissociation between P waves and QRS complexes
Complete (third-degree) AV block is characterized on ECG by complete dissociation between atrial P waves and ventricular QRS complexes, with the ventricles beating independently at a slow escape rate.
Question 3: A 3-year-old presents with high fever, drooling, muffled 'hot potato' voice, and reluctance to move the neck. He sits in a tripod position and appears toxic. What is the most dangerous diagnosis to exclude?
- Croup
- Epiglottitis (Correct answer)
- Peritonsillar abscess
- Ludwig's angina
Correct answer: Epiglottitis
Epiglottitis (most commonly due to Haemophilus influenzae type b pre-vaccination era, now Streptococcus/Staphylococcus) is a life-threatening emergency presenting with high fever, drooling, muffled voice, and the tripod position; airway management takes priority.
Question 4: Which organism is the most common cause of bacterial meningitis in children aged 1 month to 5 years?
- Listeria monocytogenes
- Neisseria meningitidis
- Streptococcus pneumoniae (Correct answer)
- Haemophilus influenzae type b
Correct answer: Streptococcus pneumoniae
Streptococcus pneumoniae is the most common cause of bacterial meningitis in children over 1 month of age (along with Neisseria meningitidis), with pneumococcal meningitis carrying a higher mortality and complication rate.
Question 5: A 7-year-old boy with known asthma presents with a wheeze, respiratory rate of 40/min, SpO2 88% on air, and is unable to complete sentences. What severity of asthma attack is this?
- Mild acute asthma
- Moderate acute asthma
- Severe acute asthma
- Life-threatening asthma (Correct answer)
Correct answer: Life-threatening asthma
Life-threatening asthma in children includes SpO2 <92%, silent chest, cyanosis, poor respiratory effort, exhaustion, or altered consciousness; SpO2 of 88% meets this threshold and requires immediate aggressive management.
Question 6: What is the recommended maintenance fluid for children in most UK pediatric settings?
- 0.9% normal saline alone
- 0.9% NaCl with 5% dextrose (Correct answer)
- 0.45% NaCl with 5% dextrose
- 5% dextrose alone
Correct answer: 0.9% NaCl with 5% dextrose
Current NICE guidelines recommend isotonic fluids (0.9% NaCl with 5% dextrose) for pediatric maintenance to reduce the risk of hyponatremia that occurred with hypotonic solutions.
PLAB PLAB Pediatrics & Child Health 2
A 4-year-old child presents with a widespread purpuric rash, arthritis, colicky abdominal pain, and haematuria.
What is the most likely diagnosis?