GERD: Barrett Esophagus, Hiatal Hernia & PPIs

Creator: Progress Note
Published: 2026-08-27
Keywords: GERD, gerd usmle, barrett esophagus histology, esophageal adenocarcinoma vs squamous, sliding vs paraesophageal hernia, achalasia bird beak, eosinophilic esophagitis, ppi adverse effects, h2 blocker cimetidine, lower esophageal sphincter

bolt The 60-second version

check_circleGERD results from transient LES relaxations or a hypotensive LES; risks include obesity, hiatal hernia, pregnancy, smoking, alcohol, and systemic sclerosis.
check_circleClassic symptoms are heartburn and regurgitation; atypical ones include chronic cough, hoarseness, asthma, and dental erosion. Always consider angina in chest pain.
check_circleBarrett esophagus: distal esophageal squamous epithelium replaced by nonciliated columnar epithelium with goblet cells (intestinal metaplasia); it raises the risk of adenocarcinoma.
check_circleEsophageal adenocarcinoma arises in the distal third (GERD, Barrett, obesity); squamous cell carcinoma arises in the upper and middle thirds (smoking, alcohol, hot liquids, achalasia).
check_circleSliding hiatal hernia (most common): the GE junction moves above the diaphragm. Paraesophageal hernia: the GE junction stays put and the fundus herniates; risk of strangulation.
check_circlePPIs irreversibly inhibit the parietal cell H⁺/K⁺-ATPase; long-term risks include C. difficile infection, hypomagnesemia, and reduced absorption of B₁₂, iron, and calcium.

target What you'll be able to do · aligned to USMLE Step 1 · Gastrointestinal

PHYSExplain how LES dysfunction and hiatal hernias cause reflux.
PATHDescribe Barrett esophagus and compare esophageal adenocarcinoma with squamous cell carcinoma.
GIDifferentiate GERD from achalasia, eosinophilic, pill, and infectious esophagitis.
PHARMDescribe the mechanisms and adverse effects of PPIs, H₂ blockers, and antacids.

How GERD is tested on Step 1

Vignettes describe burning chest pain after meals or when lying down, then ask about mechanism, complication, histology, or drug.

The reflux sequence. Barrett esophagus is metaplasia, an adaptation, and is reversible in principle; dysplasia is the precursor lesion.

Factor	Effect on reflux
Obesity, pregnancy	↑ intra-abdominal pressure
Hiatal hernia	Loss of the diaphragm's support of the LES
Smoking, alcohol, fatty meals, caffeine, chocolate	↓ LES tone or ↑ transient relaxations
Systemic sclerosis	Fibrosis of esophageal smooth muscle → weak LES and poor peristalsis
Anticholinergics, calcium channel blockers, nitrates	↓ LES tone

The LES is a high-pressure zone of smooth muscle maintained by intrinsic tone and the crural diaphragm.

Barrett esophagus and esophageal cancer

Metaplasia is the most-tested pathology concept in GERD.

Esophageal cancer. Both present with progressive dysphagia (solids, then liquids) and weight loss.

Hiatal hernias and GERD mimics

Know which disorders cause dysphagia or chest pain and how they look on studies.

GERD mimics. Infectious esophagitis suggests immunosuppression: Candida (white plaques), HSV (punched-out ulcers), CMV (linear ulcers).

Condition	Key feature
Sliding hiatal hernia	GE junction displaced upward; "hourglass stomach"; causes reflux
Paraesophageal hernia	GE junction normal; fundus beside the esophagus; may strangulate
Achalasia	Loss of myenteric (Auerbach) inhibitory neurons (NO, VIP) → incomplete LES relaxation, absent peristalsis; dysphagia to solids and liquids
Eosinophilic esophagitis	Atopy; stacked rings and furrows; ≥ 15 eosinophils per high-power field
Mallory-Weiss vs Boerhaave	Mucosal tear with hematemesis vs transmural rupture with mediastinitis

Chagas disease (Trypanosoma cruzi) can cause secondary achalasia.

Acid-suppressing drugs

Mechanisms and adverse effects are high yield.

Drug	Mechanism	Adverse effects
PPIs (-prazole)	Irreversible H⁺/K⁺-ATPase inhibition in parietal cells	C. difficile, pneumonia, hypomagnesemia, ↓ B₁₂/iron/Ca²⁺ absorption, fractures
H₂ blockers (-tidine)	Reversible H₂ receptor block → ↓ acid	Cimetidine: CYP450 inhibition, antiandrogenic effects, crosses placenta
Antacids	Neutralize acid	Al(OH)₃ constipation, hypophosphatemia; Mg(OH)₂ diarrhea; CaCO₃ hypercalcemia, rebound acid
Sucralfate	Coats ulcer base in acid environment	Needs acid to work; separate from PPIs

Surgical option for refractory GERD: Nissen fundoplication (fundus wrapped around the distal esophagus).

Worked example

Link chronic reflux to histology.

functions Worked example — long-standing heartburn

A 58-year-old man with obesity and 15 years of heartburn has salmon-colored mucosa extending up from the GE junction on endoscopy. Biopsy shows columnar epithelium with goblet cells. What is the process, and what cancer is he at risk for?

Chronic acid exposure injures the normal stratified squamous epithelium.
It is replaced by intestinal-type columnar epithelium with goblet cells: metaplasia (Barrett esophagus).
Metaplasia can progress to dysplasia and then carcinoma.
The cancer arises in the distal esophagus and is glandular.

Answer. Barrett esophagus (intestinal metaplasia), with increased risk of esophageal adenocarcinoma.

Next in the roadmap

GERD

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quiz Test yourself

Quick check — 3 questions

1. A biopsy of the distal esophagus shows columnar cells with goblet cells. This change is best described as:

2. A patient with dysphagia to solids and liquids has a dilated esophagus that tapers to a "bird beak." What is lost?

3. Which drug irreversibly inhibits the parietal cell proton pump?

Frequently asked questions

What defines Barrett esophagus histologically?expand_more

Replacement of distal esophageal squamous epithelium by nonciliated columnar epithelium with goblet cells (intestinal metaplasia).

Where do esophageal adenocarcinoma and squamous cell carcinoma arise?expand_more

Adenocarcinoma arises in the distal third (GERD, Barrett); squamous cell carcinoma in the upper and middle thirds (smoking, alcohol).

How do sliding and paraesophageal hiatal hernias differ?expand_more

In a sliding hernia the GE junction moves above the diaphragm; in a paraesophageal hernia the GE junction stays in place and the fundus herniates beside it.

Why do long-term PPIs cause hypomagnesemia and low B₁₂?expand_more

They reduce intestinal magnesium absorption and remove the acid needed to release B₁₂ from food protein.

References & further reading

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