NAC OSCE Paediatric Assessment 2 — Questions and Answers
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?
- Gastroesophageal reflux
- Pyloric stenosis — hypertrophy of the pyloric sphincter causing gastric outlet obstruction, diagnosed by ultrasound and treated surgically (pyloromyotomy) (Correct answer)
- Intussusception
- Viral gastroenteritis
Correct answer: Pyloric stenosis — hypertrophy of the pyloric sphincter causing gastric outlet obstruction, diagnosed by ultrasound and treated surgically (pyloromyotomy)
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)?
- Blood cultures
- Clean-catch midstream urine for urinalysis and culture, or catheter/suprapubic aspirate specimen in non-toilet-trained children (Correct answer)
- CT abdomen
- Intravenous pyelogram
Correct answer: Clean-catch midstream urine for urinalysis and culture, or catheter/suprapubic aspirate specimen in non-toilet-trained children
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?
- Asthma
- Foreign body aspiration — the hyperinflation is caused by a ball-valve mechanism where air enters but cannot escape past the foreign body (Correct answer)
- Right-sided pneumonia
- Pneumothorax
Correct answer: Foreign body aspiration — the hyperinflation is caused by a ball-valve mechanism where air enters but cannot escape past the foreign body
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?
- A screening test for congenital heart disease
- 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 (Correct answer)
- A developmental milestone assessment tool
- A pain scale for neonates
Correct 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
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?
- Colic
- Intussusception — telescoping of one segment of bowel into another, most commonly ileocolic, requiring urgent air or contrast enema for diagnosis and reduction (Correct answer)
- Constipation
- Gastroenteritis
Correct answer: Intussusception — telescoping of one segment of bowel into another, most commonly ileocolic, requiring urgent air or contrast enema for diagnosis and reduction
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.
Question 6: When assessing a child for non-accidental injury (NAI), which pattern of injuries should raise suspicion?
- A single bruise on the shin of a walking toddler
- Bruises in non-mobile infants, injuries inconsistent with the history given, injuries at different stages of healing, patterned injuries (belt marks, cigarette burns), and injuries in non-accidental locations (ears, neck, buttocks) (Correct answer)
- A scrape on the knee from falling off a bicycle
- A bump on the forehead from walking into a table
Correct answer: Bruises in non-mobile infants, injuries inconsistent with the history given, injuries at different stages of healing, patterned injuries (belt marks, cigarette burns), and injuries in non-accidental locations (ears, neck, buttocks)
Red flags for NAI include: injuries inconsistent with the developmental stage (bruises in pre-mobile infants — 'those who don't cruise rarely bruise'), injuries incompatible with the history, injuries at multiple stages of healing, patterned injuries (belt buckle, cigarette burns, grip marks), injuries in unusual locations (ears, neck, buttocks, genitalia), delayed presentation, and inconsistent histories between caregivers.
NAC OSCE Paediatric Assessment 2
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?