Gastroesophageal Reflux Disease (GERD)

01Pathophysiology

The lower esophageal sphincter is a tonically contracted ring of smooth muscle at the gastroesophageal junction. Under normal conditions, the LES relaxes only during swallowing to allow food passage and then returns to its resting tone, preventing gastric contents from moving retrograde. In GERD, the primary defect is transient inappropriate LES relaxation or a sustained reduction in baseline LES pressure. This allows acidic gastric contents (pH < 4) to contact the esophageal squamous epithelium, which lacks the protective mucus-bicarbonate barrier found in the stomach.

The esophageal squamous epithelium is not designed to handle prolonged acid exposure. When acid and pepsin repeatedly contact this lining, they cause direct chemical injury to the mucosa, triggering an inflammatory cascade. This explains why patients develop retrosternal burning: the pain corresponds to inflammation and irritation along the distal esophageal mucosa. The burning classically worsens after meals (increased gastric acid production and gastric distension triggering more transient LES relaxations) and in the supine position (loss of gravitational barrier to reflux).

Hiatal hernia contributes by displacing the LES above the diaphragmatic crura, which normally serve as an extrinsic pressure support. When this anatomic reinforcement is lost, the LES functions poorly, and the herniated gastric segment acts as a reservoir that re-refluxes acid into the esophagus. This is why hiatal hernia is strongly associated with more severe erosive disease.

In extraesophageal GERD, the refluxate travels proximally past the upper esophageal sphincter and contacts the larynx, pharynx, and tracheobronchial tree. This produces vagally mediated bronchospasm (chronic cough, asthma-like wheezing) and direct chemical irritation of the laryngeal mucosa (hoarseness, globus sensation, posterior laryngitis). These presentations are tested heavily because students often do not link respiratory or ENT complaints to a gastrointestinal source.

With chronic, uncontrolled acid exposure, the distal esophageal squamous epithelium undergoes intestinal metaplasia, replacing squamous cells with columnar epithelium containing goblet cells. This adaptive change is called Barrett esophagus and represents a premalignant condition with increased risk of progressing to esophageal adenocarcinoma through the metaplasia-dysplasia-carcinoma sequence.

02Classification and Clinical Manifestation

Extraesophageal Manifestations

03Diagnostic Workup

The approach to diagnosis begins with clinical assessment. A patient presenting with classic heartburn and regurgitation, without alarm features, does not require endoscopy upfront. The most appropriate initial step is an empiric trial of a proton pump inhibitor for 8 weeks. Symptom resolution effectively confirms the diagnosis and serves as both a diagnostic and therapeutic intervention. This is a heavily tested concept: do not order endoscopy or pH monitoring as the first step in a patient with uncomplicated, typical symptoms.

Upper endoscopy is indicated when alarm features are present. These include dysphagia, odynophagia, unintentional weight loss, gastrointestinal bleeding (hematemesis or melena), iron deficiency anemia, persistent vomiting, or age of onset above 60 (threshold varies by guideline, but the principle is consistent). Endoscopy is also indicated when symptoms are refractory to adequate PPI therapy. During endoscopy, biopsies should be taken from any abnormal-appearing mucosa, and four-quadrant biopsies every 1 to 2 cm are performed in suspected Barrett segments following the Seattle protocol.

24-hour ambulatory pH monitoring is the gold standard for quantifying acid exposure. It is reserved for patients with atypical or extraesophageal symptoms, those with a negative endoscopy and persistent symptoms, or preoperative evaluation before antireflux surgery. The study should be performed off PPI therapy (for 7 days) when the goal is to confirm the diagnosis, and on PPI therapy when the goal is to assess adequacy of acid suppression in refractory cases.

Esophageal manometry is not a diagnostic test for GERD itself. Its role is strictly preoperative: before performing a Nissen fundoplication, manometry must confirm adequate esophageal peristalsis and rule out conditions like achalasia, which would make a 360-degree wrap dangerous (risk of severe dysphagia in a patient who already cannot generate peristaltic force).

04Management and Treatment

Acute management centers on initiating PPI therapy and lifestyle changes simultaneously. The PPI should be taken 30 to 60 minutes before the first meal of the day because PPIs inhibit only actively secreting proton pumps, and meal-stimulated acid secretion activates these pumps maximally. This dosing nuance is a commonly tested point. The initial course is 8 weeks. If symptoms resolve completely, attempt to step down to the lowest effective dose or switch to on-demand therapy.

For patients with partial response, the next step is to optimize PPI use: confirm adherence, verify correct timing (pre-meal), and if still inadequate, escalate to twice-daily PPI dosing for another 8 weeks. Adding a bedtime H2 blocker (famotidine 20 mg) can address nocturnal acid breakthrough, though tachyphylaxis may limit long-term H2 blocker efficacy.

For truly refractory GERD (persistent symptoms despite optimized twice-daily PPI for 8 weeks), the workup must be revisited. Perform upper endoscopy (if not already done) and ambulatory pH-impedance monitoring on therapy to distinguish between inadequate acid suppression, non-acid reflux, reflux hypersensitivity, and functional heartburn. This step is critical because many patients labeled "refractory GERD" actually have functional heartburn (normal acid exposure, no symptom-reflux correlation), which requires neuromodulator therapy (tricyclic antidepressants, SSRIs) rather than escalation of acid suppression.

Surgical management with laparoscopic Nissen fundoplication is appropriate for patients with objectively confirmed GERD (positive pH testing) who have responded to PPIs but prefer not to take lifelong medication, or who have volume regurgitation not controlled by acid suppression. Preoperative manometry is mandatory to exclude achalasia or severe esophageal hypomotility, and preoperative pH testing is mandatory to confirm the diagnosis before committing to an irreversible procedure.

Long-term PPI use is associated with several complications that are tested: Clostridioides difficile infection, hypomagnesemia, bone fractures (hip, wrist, spine), vitamin B12 deficiency, iron malabsorption, acute interstitial nephritis, and fundic gland polyps. These risks should be weighed against benefits, and ongoing PPI use should have a documented indication.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most common mistake on this topic is ordering endoscopy or pH testing as the first step for a patient with classic, uncomplicated heartburn. The correct initial step in a young patient without alarm features is always an empiric PPI trial, not an invasive workup. Test-writers will include a straightforward vignette of postprandial burning and regurgitation and tempt you with endoscopy as an answer choice. Resist this unless alarm features are explicitly described.

A second frequent trap involves Barrett esophagus. Students often select "continue PPI and repeat endoscopy" for Barrett with high-grade dysplasia. The correct answer is endoscopic eradication therapy (radiofrequency ablation), not surveillance alone. Know the surveillance intervals: no dysplasia every 3 to 5 years, low-grade dysplasia every 6 to 12 months (or ablation), and high-grade dysplasia warrants intervention, not watchful waiting.

The third major testing point is the preoperative workup before fundoplication. Manometry is mandatory before surgery. If a vignette presents a patient being considered for antireflux surgery, the next step is esophageal manometry, not proceeding directly to the operating room. The purpose is to exclude achalasia, which can mimic GERD but would be worsened by a fundoplication wrap.

Finally, be alert to the extraesophageal GERD vignette. A patient with chronic cough, hoarseness, or adult-onset asthma unresponsive to standard pulmonary therapy, with a normal chest radiograph, should raise suspicion for GERD. The test is checking whether you can identify a gastrointestinal cause for what appears to be a respiratory or ENT complaint. The next step in these patients is a PPI trial, not bronchoscopy or additional pulmonary function testing.

The core competency being tested is the ability to stratify patients by severity, choose the appropriate level of workup (empiric therapy vs. endoscopy vs. pH monitoring), and understand the stepwise escalation from medical to surgical management.