From the Guidelines
Pyloric stenosis in infants is characterized by projectile vomiting shortly after feeding, typically beginning between 2-8 weeks of age, and is often accompanied by signs of dehydration, poor weight gain, and an olive-shaped mass in the upper right abdomen. The vomiting becomes progressively more forceful and may travel several feet from the infant, with parents noticing that the baby remains hungry after vomiting and eagerly feeds again 1. Weight loss or poor weight gain is common as the condition worsens, and dehydration signs include decreased urination, dry mouth, sunken fontanelle, and lethargy. Some infants develop visible peristaltic waves that move from left to right across the upper abdomen just before vomiting. A healthcare provider may feel an olive-shaped mass in the upper right abdomen, which is the thickened pyloric muscle, as described in the evaluation of vomiting in infants 1. Infants may also show signs of jaundice and metabolic alkalosis with hypochloremia and hypokalemia due to loss of stomach acid through vomiting.
Key signs and symptoms of pyloric stenosis in infants include:
- Projectile vomiting shortly after feeding
- Dehydration signs, such as decreased urination, dry mouth, sunken fontanelle, and lethargy
- Poor weight gain or weight loss
- Visible peristaltic waves moving from left to right across the upper abdomen
- An olive-shaped mass in the upper right abdomen, felt by a healthcare provider
- Jaundice and metabolic alkalosis with hypochloremia and hypokalemia.
Prompt medical attention is essential as pyloric stenosis requires surgical correction through a pyloromyotomy procedure, as indicated by the clinical evaluation and diagnosis of gastrointestinal obstruction 1. While waiting for medical care, parents should continue offering small, frequent feedings and monitor for worsening dehydration. The condition occurs due to hypertrophy of the pyloric muscle, which narrows the pyloric channel between the stomach and small intestine, preventing normal gastric emptying, as discussed in the context of gastrointestinal tract abnormalities 1.
From the Research
Signs and Symptoms of Pyloric Stenosis in Infants
The signs and symptoms of pyloric stenosis in infants include:
- Non-bilious vomiting, which can be projectile in nature 2, 3, 4, 5
- Failure to thrive secondary to gastric outlet obstruction 2
- Poor weight gain 4
- A palpable 'olive' in the abdomen, which may be less common in recent cases 3, 6
- A 'peristaltic wave' after being fed with formula or breast milk 3
- Dehydration and malnutrition, particularly in cases of late presentation 6, 4
- Deranged serum-electrolytes and acid-base imbalance, which can delay treatment and prolong hospital stay 4
Clinical Presentation
The clinical presentation of pyloric stenosis can vary, but common features include:
- Age at diagnosis, which can range from 27 to 194 days (median 51 days) 4
- Male predominance, with 84.2% of patients being male in one study 4
- Birth order, which may not always follow the typical pattern of first-born males being more commonly affected 4
- Duration of symptoms, which can range from 1 to 58 days (median 14 days) 4