Pathophysiology
Summary
Esophageal and gastric pathologies span a wide range of disorders with varying presentations. Some of the most prevalent of these conditions include diverticula, hernias, lacerative conditions, gastroesophageal reflux disease (GERD), and eosinophilic esophagitis.
A diverticulum refers to an outpouching of gastrointestinal layers. In a false diverticulum, only the mucosa and submucosa are involved, whereas a true diverticulum affects all layers, including the muscularis propria and adventitia. Zenker’s diverticulum is a false diverticulum in the posterior upper esophagus resulting from weakness of the cricopharyngeus muscle in the Killian triangle and can present with odynophagia, halitosis, and regurgitation. In hiatal hernias, the stomach herniates into the thorax through the esophageal hiatus: sliding hiatal hernias occur when the gastroesophageal junction is displaced, and paraesophageal hiatal hernias slip through the esophageal hiatus and beside the esophagus.
Lacerative conditions of the esophagus include Mallory-Weiss tears and Boerhaave syndrome. Mallory-Weiss tears are linear lacerations in the mucosa of the distal esophagus and proximal stomach and are commonly associated with alcohol abuse. Boerhaave syndrome refers to a transmural rupture of the esophagus. Both are cause by increased intragastric pressure during retching and vomiting. Mallory-Weiss tears cause mild to moderate hematemesis & epigastric pain, while the more severe Boerhaave syndrome is associated with sharp chest pain, severe hematemesis, and other serious complications like pleural effusions & septic shock.
Gastroesophageal reflux disease (GERD) occurs due to an imbalance between the lower esophageal sphincter (LES) and intragastric pressure, resulting in reflux. Risk factors include smoking, alcohol, caffeine, pregnancy, &obesity. Mild GERD often manifests as noncardiac chest pain, nocturnal cough, nocturnal asthma, or dysphagia. Severe GERD leads to erosive esophagitis, which appears as eosinophil and lymphocyte infiltration, elongation of papillae, and hypertrophy of basal cells on histology. GERD can progress to Barrett's esophagus, a metaplastic transformation involving columnar epithelium and goblet cell hyperplasia. Barrett's esophagus may progress to dysplasia and eventually esophageal adenocarcinoma. Treatment for GERD commonly involves proton pump inhibitors (PPIs) or H2 blockers.
Eosinophilic esophagitis involves epithelial infiltration of eosinophils throughout the esophagus and presents similarly to severe GERD, but is more common in children. Symptoms may also include other atopic conditions like eczema and allergic rhinitis. Unlike GERD, eosinophilic esophagitis may be resistant to PPIs.
Lesson Outline
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FAQs
Zenker's diverticulum is a false diverticulum (mucosa and submucosa only) in the posterior upper esophagus resulting from a weakness of the cricopharyngeus muscle in the Killian triangle. Common symptoms may include odynophagia (painful swallowing), halitosis (bad breath), and regurgitation. As it is a false diverticulum, it only involves outpouching of the mucosa and submucosa.
In a sliding hiatal hernia the gastroesophageal junction herniates through the esophageal hiatus. In a paraesophageal hiatal hernia the gastric cardia herniates through the esophageal hiatus, beside a normally placed esophagus. These hernias often present with gastroesophageal reflux.
Mallory-Weiss tears and Boerhaave syndrome are both caused by increased intragastric pressure during retching and vomiting. Mallory-Weiss tears consist of linear longitudinal lacerations in the mucosa of the distal esophagus and proximal stomach, often seen in alcoholics, and present with mild to moderate hematemesis and epigastric pain. Boerhaave syndrome refers to a transmural rupture of the esophagus, leading to severe sharp chest pain, severe hematemesis, subcutaneous emphysema, along with other serious complications such as pleural effusions, fever, sepsis, and septic shock.
GERD is an imbalance between LES tone and intragastric pressure causing reflux of gastric acid into the esophagus. Some common risk factors include decreased LES tone, smoking, alcohol use, caffeine, pregnancy, and obesity. GERD often presents with noncardiac chest pain such as heartburn or indigestion, nocturnal cough, nocturnal asthma, or dysphagia (difficulty swallowing). It can progress to erosive esophagitis or esophageal ulcers.
Prolonged GERD can lead to Barrett's esophagus, where there is intestinal metaplasia of the distal esophagus. The esophagus, normally lined with stratified squamous epithelium, becomes lined with columnar epithelium containing goblet cell hyperplasia. Barrett’s esophagus (metaplasia) can progress to dysplasia, and eventually cancer such as esophageal adenocarcinoma, highlighting the importance of managing GERD effectively.
