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?

 

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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

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