Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Gastroesophageal Reflux Disease

Popularly known as heartburn, gastroesophageal reflux disease (GERD) refers to backflow of gastric or duodenal contents or both into the esophagus and past the lower esophageal sphincter (LES), without associated belching or vomiting. The reflux of gastric contents causes acute epigastric pain, usually after a meal. The pain may radiate to the chest or arms. It commonly occurs in pregnant or obese persons. Lying down after a meal may also contribute to reflux.

Causes

·   Weak esophageal sphincter

·   Increased abdominal pressure, as in obesity or pregnancy

·   Hiatal hernia

·   Medications, such as morphine, meperidine, diazepam, calcium channel blockers, anticholinergic agents

·   Alcohol, cigarette smoke

·   Nasogastric intubation for longer than 4 days

·   Pyloric surgery

Pathophysiology

Normally, the LES maintains enough pressure around the lower end of the esophagus to close it and prevent reflux. Typically, the sphincter relaxes after each swallow to allow food into the stomach. In GERD, the sphincter doesn't remain closed (usually due to deficient LES pressure or pressure within the stomach exceeding LES pressure) and stomach contents flow into the esophagus. The high acidity of the stomach contents causes pain and irritation in the esophagus, and stricture or ulceration may occur.

Signs and symptoms

·   Burning epigastric pain, possibly radiating to arms and chest, usually after a meal or when lying down

·   Feeling of fluid accumulation in the throat without a sour or bitter taste

·   Dyspepsia

·   Chronic cough

·   Laryngitis and morning hoarseness

·   Wheezing

·   Nausea and vomiting

Diagnostic test results

·   Esophageal acidity test evaluates the competence of the LES and provides objective measure of reflux.

·   Acid perfusion test confirms esophagitis and distinguishes it from cardiac disorders.

·   Esophagoscopy allows visual examination of the lining of the esophagus to reveal the extent of the disease and confirm pathologic changes in mucosa.

·   Barium swallow identifies hiatal hernia as the cause.

·   Upper GI series detects hiatal hernia or motility problems.

·   Esophageal manometry evaluates resting pressure of the LES and determines sphincter competence.

Treatment

·   Frequent, small meals; avoidance of eating just before going to bed

·   Sitting up during and after meals; sleeping with head of bed elevated

·   Increased fluid intake

·   Antacids, histamine-2 receptor antagonists

·   Proton pump inhibitors

·   Smoking cessation; reduction or cessation of alcohol intake

·   Hiatal hernia repair

·   Vagotomy or pyloroplasty

Clinical Tip

Advise patients with GERD to avoid foods that irritate the LES, such as caffeine, mint, and chocolate.

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GASTROESOPHAGEAL REFLUX

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