The following supine abdominal x-ray is from a 7 week old male infant with a 10 day history of vomiting. What can you observe in the x-ray?
The supine abdominal x-ray shows a distended stomach with a mottled appearance due to food particles. There is scanty bowel gas.
These x-ray features are concerning for an obstruction of the gastric outlet and in a 7 week old baby, the most likely cause would be hypertrophic pyloric stenosis. This diagnosis was confirmed on an ultrasound.
Hypertrophic pyloric stenosis:
- Incidence is 1 in 250 live births; four times higher in boys than girls
- Risk factors are white race, 1st born and a positive family history
- Presents between 2 and 8 weeks of age with projectile, non bilious vomiting, weight loss and dehydration
- Main electrolyte abnormality is hypokalaemic, hypochloraemic metabolic alkalosis.
- Once diagnosed, an immediate referral to a paediatric surgeon is needed.
Of note, x-ray is not a sensitive imaging test to detect hypertrophic pyloric stenosis; an ultrasound scan is.
Plain film findings can be:
1. gastric distension
2. mottled retained gastric contents
3. diminished air beyond pylorus
4. Indentation in the gastric wall by hyperperistaltic waves (caterpillar stomach)
Reference: Tintinalli’s Emergency Medicine, A comprehensive study guide, 7th edition & Duke Radiology Case Review, 2nd edition