Pediatrics

Question 1

Absent thymic shadow

Answer 1

DiGeorge syndrome
Deletion of chromosome 22q11.2
The most important
factor to memorize here is the absent thymic shadow which is pathognomic for
DiGeorge syndrome
Mnemonic: CATCH-22
• Cardiac abnormality (commonly interrupted aortic arch, truncus arteriosus and
tetralogy of Fallot)
• Abnormal facies
• Thymic aplasia
• Cleft palate
• Hypocalcaemia/Hypoparathyroidism
• With the 22 to remind one the chromosomal abnormality is found on the 22
chromosome

Question 2

Olive shaped abdominal mass

Answer 2

pyloric stenosis
Presentation:
- Projectile non-bilious vomiting
- Age group: 3-8 weeks
- Olive sized abdominal mass
- The child will feel hungry and want to feed despite constant vomiting
Diagnosis:
- Abdominal ultrasound
Treatment:
- Metabolic alkalosis – correct electrolyte imbalance + hydration
- Then referral to paediatric surgery (pyloromyotomy) + nasogastric tube

Question 3

sudden onset of green, bilious vomiting and blood per rectum in neonates

Answer 3

When you see sudden onset of green, bilious vomiting and blood per rectum in
neonates for PLAB 1, think of malrotation with volvulus. PLAB 1 may have abdominal xray result as “double bubble sign”. Pyloric stenosis in PLAB 1 would have projectile
vomiting as a key feature and the age would be older than 3 weeks. Intussusception is
uncommon in neonates and would most likely occur in infants 6 months or older. Note
that it may be possible in PLAB 1 for them to show an x-ray for case stems so instead
having a description of the result you may need to interpret the radiology yourself.
Malrotation and volvulus
Presentation:
- Green, bilious vomiting
- Blood per rectum
- Sudden onset
- Age: neonates
Diagnosis:
- Abdominal x-ray
- Barium enema
Treatment:
- ABCDE protocol
- Decompression with nasogastric tube
- Referral to paediatric surgery for laparotomy and resection