Overview
Definition
Hypertrophy and hyperplasia of the pyloric sphincter muscle, causing gastric outlet obstruction.
Epidemiology
Typically presents at 3-6 weeks of life. More common in first-born males (4:1 ratio). Associated with macrolide use (Erythromycin) in early infancy.
Etiology & Risk Factors
- Hypertrophy of circular muscle fibers of pylorus, etiology unclear
Clinical Symptoms
- Non-bilious, projectile vomiting immediately after feeding (infant is hungry immediately after - 'hungry vomiter')
- Dehydration and weight loss
- Palpable 'olive-shaped' mass in the epigastrium (pathognomonic)
- Visible peristaltic waves moving from left to right across abdomen
Clinical Approach
Diagnosis
- Abdominal Ultrasound showing pyloric muscle thickness >= 4mm and length >= 14mm
- Labs: Hypokalemic, hypochloremic metabolic alkalosis (due to loss of HCl from vomiting)
Management
- Intravenous fluid resuscitation and correction of electrolyte imbalances (MUST correct alkalosis/dehydration BEFORE surgery to prevent postoperative apnea)
- Surgical pyloromyotomy (Ramstedt procedure)
Complications
- Severe dehydration / Shock
- Aspiration pneumonia