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Etiology:

• By definition, reflux esophagitis is caused by increased contact with gastric acid through reflux
• However, more factors than simple reflux are involved(see pathogenesis)

Pathogenesis:

• Multifactorial including components of the following events:
• Decreased competency of the lower esophageal sphincter(LES) which may be due to: transient LES relaxation(most common mechanism); anatomic abnormalities of the LES such as sliding hiatus hernia: intrinsic hypotonality of the LES muscle
• Decreased or inadequate mucosal mechanisms such as: slowed esophageal acid clearance; decreased esophageal HCO3 secretion; insufficient H ion clearance pump intramucosally

Epidemiology:

• In the U.S, 7% of the population have daily and 15% monthly evidence of GERD
• 50-70% of pregnant women have evidence of GERD
• 50-75% of people with GERD have documented esophagitis equalling 3-4% of the general population
• Older people have a slightly higher incidence of esophagitis
• GERD is equally prevalent in males and females but esophagitis shows an increased incidence in males, 2-3:1

General Gross Description:

• Unless removed for some other reason, large esophageal specimens with reflux esophagitis are not seen
• The endoscopic appearance of reflux esophagitis uncomplicated by ulceration, Barrett's esophagus or stricture

General Microscopic Description:

• The most reproducible and earliest finding is the presence of eosinophiles and/or neutrophiles
• There may be hyperplasia of the basal epithelial zone which normally occupies a maximum of 10-15% of the thickness of the epithelium
• Hyperplasia of the basal zone is accompanied by thickening of the epithelium with increase in the hight of the vascular papillae of the laminar propria to greater than 50% of the thickness of the epithelium
• The histologic complications of reflux such as ulceration and stricture are described separately

Clinical Correlations:

• The most common cause of esophagitis is gastroesophageal reflux
• Of people with gastroesophageal reflux disease(GERD) 50-70% will develop esophagitis(histologically proven)
• The most common symptoms of GERD are Heartburn(>50%), dysphagia(>30%) and regurgitation
• The major complications are Barrett's epithelium(15%), peptic stricture(15%) and significant GI bleeding(2%)

References:
Cotran RS, Kumar V, Robbins SL. Robbins Pathologic Basis of Disease, 5th edition. W.B. Saunders. Philadelphia, 1994, pp.761-762 Sleisenger MH and Fordtran JS Gastrointestinal Disease 5th Edition W.B.Saunders Philadelphia, 1993, pp.378-401