Symptoms of Pyloric Stenosis
Pyloric stenosis is characterized by progressive projectile non-bilious vomiting, which is the hallmark symptom of this condition. 1
Key Clinical Manifestations
Primary Symptoms
- Projectile vomiting: Non-bilious vomiting that becomes progressively more forceful and projectile 2, 1
- Feeding difficulties: Eagerness to feed despite recent vomiting episodes 3
- Persistent hunger: Infants remain hungry after vomiting and want to feed again immediately
Physical Examination Findings
- Palpable olive-shaped mass: A firm, mobile mass in the right upper quadrant of the abdomen, though this finding has become less common with earlier diagnosis 4
- Visible peristaltic waves: Moving from left to right across the upper abdomen after feeding 3
- Dehydration signs: As the condition progresses, signs of dehydration may develop 4
Metabolic Abnormalities
- Hypochloremic metabolic alkalosis: Due to loss of hydrochloric acid from stomach through vomiting 4
- Elevated BUN/creatinine: Indicating dehydration as the condition progresses 4
Demographic and Timing Considerations
- Typically presents between 2-8 weeks of age
- More common in male infants (male to female ratio approximately 4:1) 4, 3
- Average age at diagnosis has been increasing in recent years (from 37.4 to 43.3 days in one study) 4
Diagnostic Evolution
The presentation of pyloric stenosis has been changing over time:
- Earlier diagnosis due to improved imaging techniques 4
- Decreased frequency of palpable olive-shaped mass on physical examination 4
- Less severe metabolic derangements due to earlier intervention 4
Diagnostic Approach
- Ultrasound: Gold standard for diagnosis showing:
- Pyloric muscle thickness >3mm
- Channel length >15-18mm
- Target sign on transverse view
- Lack of gastric emptying 5
- Point-of-care ultrasound (POCUS): Can provide immediate diagnosis in the emergency department 5
- If initial ultrasound is negative but symptoms persist, repeat ultrasound is warranted as false negatives can occur 5
Differential Diagnosis
- Gastroesophageal reflux
- Gastroenteritis
- Formula intolerance
- Malrotation with volvulus (bilious vomiting)
- Increased intracranial pressure 2
Pitfalls and Caveats
- Not all infants will present with the classic "olive" mass, especially with earlier diagnosis 4
- A negative initial ultrasound does not rule out pyloric stenosis if clinical suspicion remains high 5
- Bilious vomiting suggests a different diagnosis and requires urgent evaluation for malrotation with volvulus 2
- Symptoms may be confused with common reflux, delaying diagnosis
Pyloric stenosis requires surgical intervention (pyloromyotomy) after appropriate fluid and electrolyte resuscitation, with excellent outcomes when properly managed 1.