NAC OSCE Paediatric Assessment 2

Question 1

A 3-week-old infant presents with projectile vomiting after feeds and a palpable 'olive-shaped' mass in the right upper quadrant. What is the MOST likely diagnosis?

Accepted Answer

Pyloric stenosis — hypertrophy of the pyloric sphincter causing gastric outlet obstruction, diagnosed by ultrasound and treated surgically (pyloromyotomy)

Answer

Pyloric stenosis classically presents at 2-8 weeks of age with non-bilious projectile vomiting, a 'hungry baby' who feeds eagerly after vomiting, visible gastric peristalsis, and a palpable 'olive' in the right upper quadrant. Diagnosis is confirmed by abdominal ultrasound (pyloric muscle thickness >3mm, length >15mm). Treatment is surgical pyloromyotomy (Ramstedt's procedure) after correcting the metabolic alkalosis.

Question 2

What is the MOST appropriate initial investigation for a child presenting with suspected urinary tract infection (UTI)?

Accepted Answer

Clean-catch midstream urine for urinalysis and culture, or catheter/suprapubic aspirate specimen in non-toilet-trained children

Answer

A properly collected urine specimen is essential. In toilet-trained children, a clean-catch midstream specimen is appropriate. In non-toilet-trained infants and young children, catheter specimen or suprapubic aspiration provides the most reliable results. Bag specimens have high contamination rates and should only be used for screening. UTI diagnosis requires both positive urinalysis (pyuria, nitrites) and culture (>100,000 CFU/mL).

Question 3

A 2-year-old presents with sudden onset of choking and unilateral wheezing. Chest X-ray shows hyperinflation of the right lung. What is the MOST likely diagnosis?

Accepted Answer

Foreign body aspiration — the hyperinflation is caused by a ball-valve mechanism where air enters but cannot escape past the foreign body

Answer

Sudden onset of choking in a toddler with unilateral wheezing and hyperinflation on one side strongly suggests foreign body aspiration. The hyperinflation occurs because the foreign body acts as a ball valve, allowing air in during inspiration but trapping it during expiration. The right main bronchus is more commonly affected due to its straighter, wider angle. Rigid bronchoscopy is both diagnostic and therapeutic.

Question 4

What is the Apgar score and what does each component assess?

Accepted Answer

A scoring system assessed at 1 and 5 minutes after birth evaluating Appearance (colour), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration (breathing effort), each scored 0-2

Answer

The Apgar score is assessed at 1 minute (identifies need for immediate intervention) and 5 minutes (assesses response to resuscitation) after birth. Each of the 5 components is scored 0-2: Appearance (skin colour), Pulse (heart rate), Grimace (reflex response to stimulation), Activity (muscle tone), Respiration (breathing effort). Maximum score is 10. A score of 7-10 is normal, 4-6 requires intervention, and 0-3 requires aggressive resuscitation.

Question 5

A 10-month-old infant presents with paroxysmal episodes of inconsolable crying, drawing up of the legs, and 'red currant jelly' stools. What is the MOST likely diagnosis?

Accepted Answer

Intussusception — telescoping of one segment of bowel into another, most commonly ileocolic, requiring urgent air or contrast enema for diagnosis and reduction

Answer

The classic triad of intussusception is: (1) colicky abdominal pain with drawing up of the legs, (2) vomiting, and (3) 'red currant jelly' stools (blood and mucus from bowel ischemia). A 'sausage-shaped' mass may be palpable in the right upper quadrant. Diagnosis and treatment is by air or contrast enema (>90% reduction rate). Surgery is required if enema reduction fails or if there is perforation.

NAC OSCE Practice Test

NAC OSCE Practice Test

NAC OSCE Paediatric Assessment 2