P1) Non-bilious vomiting in an infant

Review the Learning Outcomes, Hx, PE and Labs, and begin the module with your Provisional Diagnosis. Keep hitting "Next" to move through the module.

Learning Outcomes

  1. Articulate your relationship with the consulting diagnostic radiologists in the evaluation of a patient with vomiting.
  2. Review the DDx considerations in a patient with vomiting.
  3. Identify the spectrum of imaging findings in appropriate modalities for evaluating a patient with vomiting.


Physical Exam


Provisional Diagnosis

Select the Dx you believe is most appropriate
This patient most likely has hypertrophic pyloric stenosis considering the risk factors (preterm birth, macrolide use) presentation (non-bilious, “hungry vomiter,” failure to thrive, dehydration, peristaltic waves, olive shaped mass) and laboratory findings (hypochloremic hypokalemic metabolic alkalosis).
Well done. You were correct

Potential Acuity

What is your assessment of the likely acuity for this patient?

Well done. You were correct
The patient requires urgent workup for their condition.

First Imaging Study

What is the first imaging study you will order?

The abdominal ultrasound is the best initial imaging modality to evaluate for hypertrophic pyloric stenosis. It avoids radiation exposure and can evaluate for abnormal thickening of the pylorus.
Well done. You were correct

Pertinent Imaging Observations

Click on the links below to view images from the study, and assess these key findings as best you can.

Watch our video

View the full study if you'd like to take a look yourself.

Second Imaging Study

What is the next imaging study you will order?

No further imaging is needed as the diagnosis is confirmed with ultrasound.
Well done. You were correct

What is your Diagnosis now that you have seen the imaging results?

This patient has severe dehydration secondary to their hypertrophic pyloric stenosis, as evidenced by the physical exam findings.

Current Acuity

Initially, you selected and we suggested acuity.

Has your concern for this patient changed?

The patient will require urgent workup and management.

Assessment and Plan

Please provide your assessment and plan for this patient

This patient is a 3-year-old male presenting with hypertrophic pyloric stenosis. He will require aggressive IV fluid rehydration and correction of electrolyte abnormalities. We will consult pediatric surgery to evaluate for pyloromyotomy following resuscitation.

Lessons Learned:
- Pyloric stenosis is more likely to occur in preterm male, first-born children who were treated with erythromycin and with a mother who smoked during pregnancy. These factors are all individually associated with increased risk.
- The diagnosis should be suspected in a baby between 2-8 weeks of age presenting with non-bilious vomiting immediately after feeding.
-  The first best diagnostic modality is an abdominal ultrasound and reveals and elongated (>12mm) and thickened (>3mm) pylorus. X-ray may suggest gastric outlet obstruction stomach distension.

Socioeconomic Factors: Patients with lower socioeconomic status and who are formula-fed have increased incidence of pyloric stenosis.

That's the end of the module! Once you've reviewed the video(s), you can click here for another case challenge.

Kevin Pierre, MD - Editor
Robbie Slater, MD - Supervising Editor
Bayar Batmunh, MS - Coordinator