A 12 day old boy presents with vomiting every feed for 3 days.  He has lost 4% of his body weight since birth.  An ultrasound is shown below.  What's the diagnosis?  Scroll down for answer.

Answer: pyloric stenosis

History

• projectile, non-bilious vomiting after feeds
• patient will be hungry after feeds ("hunger vomiter")
• may have decreased urine output (dehydration), weight loss suggesting this is not just reflux / overfeeding
• commonly in first born males (4 times more common in males), typically presents between 3-5 weeks, should suspect in any infant with these symptoms

Exam

• classically can palpate "olive-like" mass in abdomen, however is often not appreciated

Diagnosis

• Ultrasound - pylorous length over 15mm and thickness greater than 3mm are diagnositc

Management

• pediatric surgery consult for pylorotomy which is definitive treatment
• evaluate with chemistry, patients are at risk for hypochloremic metabolic alkalosis from gastric acid loss, treat with IV fluids

References:

Olivé, Anthony P, and Erin E Endom . “Infantile Hypertrophic Pyloric Stenosis.” UpToDate, 22 Jan. 2020. https://www.uptodate.com/contents/infantile-hypertrophic-pyloric-stenosis?search=pyloric%20stensosi&source=search_result&selectedTitle=1~91&usage_type=default&display_rank=1