What are the clinical differences between Gastroesophageal Reflux Disease (GERD) and pyloric stenosis?

Clinical Differentiation Between GERD and Pyloric Stenosis

GERD and pyloric stenosis are fundamentally different conditions distinguished by age of presentation, vomiting characteristics, physical examination findings, and metabolic derangements—with pyloric stenosis presenting as progressive projectile non-bilious vomiting with a palpable "olive" mass in infants aged 3-6 weeks, while GERD presents as chronic heartburn and regurgitation typically in older children and adults.

Age and Demographics

Pyloric Stenosis:

• Presents classically during the third to fourth week of life (median age 30-40 days, range 9-90 days) 1, 2
• Male predominance is striking, affecting 78-81% of cases 1, 2
• Firstborn children account for approximately 43% of cases 2

GERD:

• Can occur at any age but the guidelines focus primarily on adult and older pediatric populations 3
• No specific gender predominance in the adult population 3

Vomiting Characteristics

Pyloric Stenosis:

• Progressive projectile non-bilious vomiting is the hallmark, though this "classical" presentation is absent in one-third of patients 4, 2
• Vomiting occurs despite good appetite initially 2
• Symptoms typically begin around 24 days of age with median duration of 7-8 days before diagnosis 1, 2
• Large residual gastric aspirate (≥10 mL after 3-4 hour fast) occurs in 91.7% of pyloric stenosis cases 5

GERD:

• Presents with troublesome heartburn and regurgitation as typical symptoms 3
• Non-cardiac chest pain may occur 3
• Symptoms are chronic and episodic rather than progressive 3
• Extraesophageal manifestations include chronic cough, laryngitis, hoarseness, and asthma 3

Physical Examination Findings

Pyloric Stenosis:

• Palpable pyloric "olive" or tumor is pathognomonic but found in only 50% of cases in modern series (declining due to earlier imaging) 2
• Visible gastric peristaltic wave after feeding may be observed 2
• Signs of dehydration present in only 9% of contemporary cases due to earlier diagnosis 1

GERD:

• No specific physical examination findings 3
• Physical exam is generally unremarkable unless complications exist 3

Laboratory and Metabolic Findings

Pyloric Stenosis:

• Hypochloremic, hypokalemic metabolic alkalosis is the classic laboratory finding 4, 2, 6
• However, in modern series with earlier diagnosis: metabolic alkalosis occurs in only 20-25%, hypochloremia in one-third, and hypokalemia in only 3% 1, 2
• Bicarbonate >28 mEq/L in only 20% and pH >7.45 in only 25% of contemporary cases 2
• Metabolic acidosis can occur in 5% of cases 1

GERD:

• No characteristic laboratory abnormalities 3
• Laboratory testing is not part of routine GERD evaluation 3

Diagnostic Imaging

Pyloric Stenosis:

• Ultrasound is the diagnostic modality of choice, showing thickened pyloric muscle 1, 4, 2
• Pyloric length ≥24 mm correlates with longer symptom duration 2
• Upper GI series can demonstrate gastric outlet obstruction but is less commonly used 2
• Nasogastric aspirate ≥10 mL after fasting suggests pyloric stenosis and indicates ultrasound should be performed 5

GERD:

• Upper endoscopy is indicated for alarm symptoms, PPI non-response, or screening for Barrett's esophagus 3
• 96-hour wireless pH monitoring off PPI is preferred for objective diagnosis when endoscopy is negative 3, 7
• Endoscopy assesses for erosive esophagitis (Los Angeles grade B or greater) or Barrett's esophagus 3, 7

Treatment Approach

Pyloric Stenosis:

• Fredet-Ramstedt pyloromyotomy is the definitive treatment with excellent outcomes 4, 6
• Preoperative resuscitation to correct fluid and electrolyte abnormalities when present 4
• Medical management with atropine sulfate is an alternative but less commonly used 6
• Postoperative stay averages 2.8 days with total hospitalization 3.8 days 1

GERD:

• 4-8 week trial of single-dose PPI therapy for typical symptoms without alarm features, escalating to twice daily if needed 3
• Lifestyle modifications including weight loss, head of bed elevation, and avoiding meals within 2-3 hours of bedtime 3, 7
• Long-term PPI therapy at lowest effective dose for confirmed GERD 3, 7
• Anti-reflux surgery reserved for carefully selected patients with confirmed pathologic GERD and adequate esophageal motility 3

Critical Pitfalls to Avoid

• Do not confuse infant regurgitation/GERD with pyloric stenosis: The progressive nature, projectile quality, and age of onset (3-6 weeks) distinguish pyloric stenosis 4, 2
• Do not rely solely on metabolic alkalosis to diagnose pyloric stenosis in the modern era—only 20-25% present with classic electrolyte abnormalities due to earlier diagnosis 1, 2
• Do not assume all infants with pyloric stenosis will have a palpable olive—this finding is present in only 50% of cases with widespread ultrasound availability 2
• In GERD, do not use PPI response alone to confirm diagnosis—placebo effects are significant and objective testing is needed for long-term management 3