GERD & Barrett's Esophagus for USMLE Step 1 Exam
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Gastroesophageal Reflux Disease (GERD) and Barrett’s Esophagus for USMLE Step 1
Definition
- Gastroesophageal Reflux Disease (GERD): A condition caused by the reflux of gastric contents into the esophagus due to dysfunction of the lower esophageal sphincter (LES). This results in symptoms like heartburn and regurgitation.
- Barrett’s Esophagus: A complication of chronic GERD where the normal esophageal squamous epithelium is replaced by columnar epithelium with intestinal metaplasia. This metaplasia increases the risk of esophageal adenocarcinoma.
Pathophysiology
GERD
- LES Dysfunction: LES relaxes inappropriately or has low pressure, allowing acid to reflux into the esophagus.
- Hiatal Hernia: The herniation of the stomach through the diaphragm weakens the LES and promotes reflux.
- Increased Intra-abdominal Pressure: Conditions like obesity and pregnancy elevate intra-abdominal pressure, promoting reflux.
- Mucosal Damage: Chronic exposure to gastric acid leads to inflammation (esophagitis), ulceration, and potentially Barrett’s esophagus.
Barrett’s Esophagus
- Chronic Acid Exposure: Persistent GERD damages the esophageal lining, causing the normal squamous epithelium to be replaced by columnar epithelium (intestinal metaplasia) to resist the acidic environment.
- Progression: Barrett’s esophagus increases the risk of dysplasia and esophageal adenocarcinoma.
Risk Factors
GERD
- Obesity: Increases intra-abdominal pressure, leading to LES dysfunction.
- Smoking: Reduces LES tone and increases acid production.
- Alcohol and Diet: Fatty foods, caffeine, alcohol, and chocolate reduce LES pressure and trigger reflux.
- Hiatal Hernia: Weakens the barrier between the stomach and esophagus.
Barrett’s Esophagus
- Chronic GERD: The most significant risk factor for Barrett’s esophagus.
- Age and Gender: More common in older adults, especially males.
- Obesity: Central obesity is strongly associated with Barrett’s esophagus.
Clinical Features
GERD
- Heartburn: A burning sensation in the chest, commonly after meals or lying down.
- Regurgitation: The sensation of acid or food moving into the throat or mouth.
- Dysphagia: Difficulty swallowing, often due to esophagitis or strictures.
- Atypical Symptoms: Chronic cough, asthma, and non-cardiac chest pain.
Barrett’s Esophagus
- Often Asymptomatic: Usually discovered during evaluation for GERD.
- Persistent GERD Symptoms: Barrett’s may be associated with worsening or persistent GERD symptoms.
- Alarm Symptoms: Dysphagia, weight loss, or GI bleeding may indicate complications such as strictures or malignancy.
Diagnosis
GERD
- Clinical Diagnosis: Based on symptoms like heartburn and regurgitation, often confirmed with a trial of proton pump inhibitors (PPIs).
- Endoscopy: Performed for alarm symptoms, treatment failure, or evaluation of complications like Barrett’s esophagus or esophagitis.
- 24-hour pH Monitoring: Confirms abnormal acid reflux in patients with atypical symptoms or when diagnosis is uncertain.
Barrett’s Esophagus
- Endoscopy with Biopsy: The gold standard for diagnosing Barrett’s esophagus. Intestinal metaplasia with goblet cells confirms the diagnosis.
- Surveillance: Endoscopic surveillance is recommended to monitor for dysplasia or progression to adenocarcinoma.
Treatment
GERD
- Lifestyle Modifications: Weight loss, dietary changes (avoid trigger foods like caffeine, fatty foods, and alcohol), elevate the head of the bed, and avoid lying down after meals.
- Proton Pump Inhibitors (PPIs): First-line treatment for GERD. PPIs reduce gastric acid secretion and promote healing of esophagitis.
- H2-Receptor Antagonists (H2RAs): Used for mild or intermittent GERD symptoms.
- Surgery (Fundoplication): Indicated for patients with refractory GERD or large hiatal hernias.
Barrett’s Esophagus
- PPI Therapy: Reduces acid exposure and may prevent progression of Barrett’s esophagus.
- Surveillance Endoscopy: Regular endoscopic evaluations with biopsy to monitor for dysplasia or adenocarcinoma.
- Endoscopic Ablation: For patients with dysplasia, radiofrequency ablation or endoscopic mucosal resection can remove abnormal tissue and prevent cancer development.
Complications
GERD
- Erosive Esophagitis: Inflammation causing erosions and ulcers in the esophagus.
- Esophageal Strictures: Scarring leads to narrowing of the esophagus, causing dysphagia.
- Aspiration Pneumonia: Refluxed gastric contents can be aspirated into the lungs, leading to pneumonia.
Barrett’s Esophagus
- Esophageal Adenocarcinoma: Barrett’s esophagus significantly increases the risk of developing esophageal cancer, particularly in patients with dysplasia.
Prevention
- GERD Management: Controlling GERD symptoms with lifestyle changes and medications reduces the risk of developing Barrett’s esophagus.
- Surveillance: Regular endoscopy in Barrett’s esophagus patients helps detect dysplasia or early-stage cancer.
Key Points
- GERD occurs due to LES dysfunction, leading to acid reflux and symptoms like heartburn and regurgitation.
- Barrett’s esophagus is a complication of chronic GERD, where the normal squamous epithelium is replaced by columnar epithelium, increasing cancer risk.
- GERD is managed with lifestyle modifications and PPIs, while Barrett’s esophagus requires surveillance and possible ablation for dysplasia.
- Complications of GERD include esophagitis, strictures, and aspiration pneumonia. Barrett’s esophagus increases the risk of esophageal adenocarcinoma.