Inspired by what appears to have been a very interesting day in the Peds ED, lets review a rare but interesting pediatric entity:

MC in Males (5:1) & firstborn children (30%)
Usually begin between 3-6 wks of age, rarely after 12 wks
Clinical Presentation:
Nonbilious emesis. Early, patient will be hungry and well appearing despite vomiting. If left untreated, the patient will develop signs of lethargy and dehydration, and even shock.
On exam, one may palpate an olive shaped mass in the RUQ or epigastrium.
May show hypokalemia, hypochloremia, metabolic alkalosis
DDx for a vomiting child is broad. If you have suspicion, obtain an abdominal US. The image shown above is classic for pyloric stenosis. Diagnostic criteria show thickened (>3mm) and elongated (>17mm) pylorus (highly sensitive and specific for pyloric stenosis). Abd XR may show a large stomach bubble. UGI may show double track sign, string sign (narrowed pyloric lumen), or beak sign.
IVF, correct electrolyte derangement, and surgery.
Surgery (a pyloromyotomy) can be delayed to allow appropriate resuscitation of the child prior to the OR.
In the spirit of the inservice season, make sure you do not confuse this entity with other interesting pediatric abdominal pathology such as:
NEC 0-1 month, often a preemie present with vomiting, distension. Abd XR shows pneumatosis intestinalis and PV gas or free air. Treatment is with antibiotics, support + NGT, and patient requires surgery consultation.
Volvulus 0-2 months (but can present at any time) with abdominal pain, distension and bilious emesis. UGI series shows corkscrew jejunum and double bubble sign. Treatment is with antibiotics, support +NGT, and patient requires surgery consultation.
Intussusception 2mo – 6 years with intermittent abdominal pain, bilious emesis, sausage mass usually in R abdomen, Abd US will show the intussusception. Treatment is reduction with air enema and surgical consultation.