USMLE Guide: Gastric Ulcer

Introduction

This USMLE guide aims to provide a comprehensive overview of gastric ulcers, including their etiology, clinical presentation, diagnosis, and management. This information will help medical students and professionals prepare for the United States Medical Licensing Examination (USMLE) and enhance their understanding of this important topic.

Table of Contents

1. Definition and Pathophysiology
2. Etiology and Risk Factors
3. Clinical Presentation
4. Diagnostic Evaluation
5. Treatment and Management
6. Complications
7. Summary and Key Points

1. Definition and Pathophysiology

A gastric ulcer is a mucosal defect that forms in the stomach lining. It occurs when there is an imbalance between aggressive factors (such as acid secretion and pepsin) and protective factors (mucosal defense mechanisms). The pathophysiology involves the erosion of the mucosal barrier, leading to exposure of the underlying tissues to gastric acid and other digestive enzymes.

2. Etiology and Risk Factors

The most common cause of gastric ulcers is chronic Helicobacter pylori (H. pylori) infection. Other risk factors include nonsteroidal anti-inflammatory drugs (NSAIDs) use, smoking, alcohol consumption, stress, and genetic predisposition.

3. Clinical Presentation

Patients with gastric ulcers often present with epigastric pain that is typically described as burning or gnawing. The pain may be aggravated by food intake and may improve with antacids or acid-suppressing medications. Other symptoms may include nausea, vomiting, early satiety, weight loss, or gastrointestinal bleeding (hematemesis or melena).

4. Diagnostic Evaluation

To diagnose gastric ulcers, several tests can be utilized:

• Upper gastrointestinal endoscopy: This is the gold standard for diagnosing gastric ulcers. It allows direct visualization and biopsy of the ulcer.
• Histopathological examination: Biopsy samples obtained during endoscopy can confirm the presence of H. pylori and rule out malignancy.
• H. pylori testing: This can be done using urea breath test, stool antigen test, or serology.
• Imaging studies: In certain cases, barium swallow or CT scan may be used to evaluate the extent and complications of gastric ulcers.

5. Treatment and Management

The management of gastric ulcers involves a combination of eradicating H. pylori infection (if present) and reducing acid secretion. The following are key treatment modalities:

• Antibiotic therapy: A combination of antibiotics (e.g., clarithromycin, amoxicillin, or metronidazole) along with a proton pump inhibitor (PPI) is used to eradicate H. pylori.
• Acid suppression: PPIs (e.g., omeprazole, pantoprazole) are prescribed to reduce gastric acid secretion and promote ulcer healing.
• Lifestyle modifications: Patients should be advised to quit smoking, avoid NSAIDs, reduce stress, and limit alcohol consumption.

6. Complications

Gastric ulcers can lead to various complications, including:

• Gastrointestinal bleeding: Ulcers can erode blood vessels, causing bleeding, which may manifest as hematemesis or melena.
• Perforation: Deep ulcers may penetrate through the gastric wall, leading to peritonitis and requiring emergency surgical intervention.
• Gastric outlet obstruction: Scarring and inflammation near the pylorus can result in partial or complete blockage of the stomach outlet.

7. Summary and Key Points

• Gastric ulcers result from an imbalance between aggressive and protective factors in the stomach lining.
• Chronic H. pylori infection and NSAIDs use are the most common causes.
• Clinical presentation includes epigastric pain, nausea, vomiting, and potential gastrointestinal bleeding.
• Diagnosis involves endoscopy, histopathological examination, and H. pylori testing.
• Treatment includes eradicating H. pylori infection with antibiotics and reducing acid secretion with PPIs.
• Complications may include bleeding, perforation, and gastric outlet obstruction.

Remember to review this guide along with additional resources to enhance your knowledge and understanding of gastric ulcers. Good luck with your USMLE preparation!