Monday, January 4, 2010


A G1P1 mother brings in her 1 month old newborn male because he is "always hungry." When you ask further, it turns out he has been having projectile nonbilious vomiting immediately after he eats, and then after the vomiting, appears to be hungry again. Right before he vomits, the mother notes quivering waves on his belly. The mother has been breastfeeding him frequently.

On exam, you note a dehydrated infant. On the abdominal exam, right upper quadrant, you appear to feel one of these at the lateral edge of the rectus abdominus muscle:
Here's a barium study:
"Oh my God," the mother says. "Is it cancer?"

Challenge: The diagnosis is easy, but what electrolyte findings do you expect in this condition?

First image is shown under GNU Free Documentation License. Second image is shown under Fair Use.


Suheil said...

Congenital Hypertrophic Pyloric stenosis.. One would expect to find Metabolic Acidosis with paradoxical aciduria and Hypokalemia... i think..

Suheil said...

and the child will also be dehydrated and acutely malnourished.. so ketosis, hypoglycemia, elevated BUN all possible..

tree said...

pyloric stenosis: hypochloremic metabolic alkalosis from the loss of HCl during vomiting; hypokalemia can develop in infants vomiting for > 3 weeks

Craig Chen said...


This is a classic presentation of infantile hypertrophic pyloric stenosis leading to obstruction of the gastric outlet. Electrolytes reveal a hypochloremic hypokalemic metabolic alkalosis. The upper GI shows a double track sign with 2 thin tracks of barium along the pyloric canal created by the compressed pyloric mucosa.

Sources: UpToDate; Wikipedia; LearningRadiology.