Chapter 24: Gastroesophageal Reflux Disease

INTRODUCTION

• Gastroesophageal reflux disease (GERD) is symptoms or complications resulting from refluxed stomach contents into the esophagus, oral cavity (including the larynx), or lungs. Episodic heartburn that is not frequent or painful enough to be bothersome is not included in the definition.

PATHOPHYSIOLOGY

• In some cases, reflux is associated with defective lower esophageal sphincter (LES) pressure or function. Patients may have decreased LES pressure from spontaneous transient LES relaxations, transient increases in intra-abdominal pressure, or an atonic LES. Some foods and medications decrease LES pressure (Table 24-1).

• Problems with other normal mucosal defense mechanisms may contribute to development of GERD, including abnormal esophageal anatomy, improper esophageal clearance of gastric fluids, reduced mucosal resistance to acid, delayed or ineffective gastric emptying, inadequate production of epidermal growth factor, and reduced salivary buffering of acid.

• Esophagitis occurs when the esophagus is repeatedly exposed to refluxed gastric contents for prolonged periods. This can progress to erosion of the squamous epithelium of the esophagus (erosive esophagitis).

• Substances that promote esophageal damage upon reflux into the esophagus include gastric acid, pepsin, bile acids, and pancreatic enzymes. Composition and volume of the refluxate and duration of exposure are the primary determinants of the consequences of gastroesophageal reflux.

• An “acid pocket” is thought to be an area of unbuffered acid in the proximal stomach that accumulates after a meal and may contribute to GERD symptoms postprandially. GERD patients are predisposed to upward migration of acid from the acid pocket, which may also be positioned above the diaphragm in patients with hiatal hernia, increasing the risk for acid reflux.

• Reflux and heartburn are common in pregnancy because of hormonal effects on LES tone and increased intra-abdominal pressure from an enlarging uterus.

• Obesity is a risk factor for GERD due to increased intra-abdominal pressure. Transient LES relaxations, an incompetent LES, and impaired esophageal motility have also been attributed to obesity.

• Complications from long-term acid reflux include esophagitis, esophageal strictures, Barrett esophagus, and esophageal adenocarcinoma.

CLINICAL PRESENTATION

• Symptom-based GERD (with or without esophageal tissue injury) typically presents with heartburn, usually described as a substernal sensation of warmth or burning rising up from the abdomen that may radiate to the neck. It may wax and wane in character and be aggravated by activities that worsen reflux (eg, recumbent position, bending-over, eating a high-fat meal). Other ...