Infantile Hypertrophic Pyloric Stenosis
Gastric Outlet Obstruction
Primary risk age: 2 to 8 Weeks of Age
- Urgency
- Severe
- Typical age
- 2 to 8 Weeks of Age
- Body system
- Neonatal (Newborns)
Typical course: 2 to 3 days total hospital stay.
Reviewed against AAP · CDC · WHO · NHS guidance Last reviewed 2026-06-13
1. Summary & Pathophysiology
Gastric Outlet Obstruction
Pathophysiology (Development Path)
Hypertrophy and hyperplasia of the circular pyloric muscle layer cause progressive narrowing and elongation of the pyloric canal, leading to complete gastric outlet obstruction.
Primary Causes & Etiology
Multifactorial; genetic predisposition, male sex (first-born males), and early erythromycin exposure.
2. Symptom Continuum
- Early Onset Signs
Spitting up or mild vomiting after feeds, which gradually increases in frequency and force.
- Progressive Phase
Non-bilious projectile vomiting immediately after feeding. The child is hungry and demands feeding again ('hungry vomiter').
- Severe Indicators
Significant dehydration, weight loss, a palpable olive-shaped mass in the right upper quadrant, visible gastric peristaltic waves, and hypokalemic hypochloriemic metabolic alkalosis.
3. Clinical Verification
Abdominal ultrasound showing pyloric muscle thickness >3mm and length >15mm.
4. Care & Elements Plan
Primary Care Treatment Plan
Correct electrolyte imbalances and dehydration with IV fluids. Once stable, perform a surgical pyloromyotomy (Fredet-Ramstedt procedure).
Home Support Elements
Not applicable. Requires inpatient stabilization and surgery.
Generic Active Ingredients (No Brands)
- Intravenous saline with potassium chloride (for electrolyte correction).
Lists active elements only. Never administer self-designed therapies.
5. Doctor Critical Lines
Critical Thresholds: When to See a Doctor
Consult a doctor immediately for persistent or projectile vomiting in an infant under 3 months of age.
6. Vaccine & Prevention
Routine Prophylaxis (Prevention)
Avoid unnecessary erythromycin exposure in newborns.
Immunization Context
No vaccine available.
7. Timelines & Outlook
Active Timeline
2 to 3 days total hospital stay.
Expected Prognosis
Excellent after pyloromyotomy. The child is typically cured and feeds normally within 24-48 hours.
Potential Untreated Complications
Severe dehydration, metabolic alkalosis, aspiration pneumonia, and failure to thrive.
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