Gastroesophageal reflux disease overview

# Overview
Gastroesophageal reflux disease is defined as chronic symptoms due to damage to the esophageal mucosa as a result of  abnormal reflux of acidic stomach contents into the esophagus.  This is commonly due to transient or permanent changes in the barrier between the esophagus and the stomach. This can be due to incompetence of the lower esophageal sphincter (LES), transient LES relaxation, impaired expulsion of gastric reflux from the esophagus, or a hiatal hernia.  Chronic GERD is associated with an increased risk of Barrett's esophagus which is a premalignant condition of the esophageal mucosa which is in turn associated with an increased risk of adenocarcinoma of the esophagus.

# Historical Perspective
GERD is believed to be first described and treated by the ancient Egyptians according to the papyrus which was discovered by Edwin Smith at Thebes. The esophagus itself was named by the ancient Greeks. Friedenwald and Feldman described the symptoms of GERD in 1925. Robbins and Jankelson used the radiological procedures to observe GERD in 1926.

# Classification
GERD can be classified based on the endoscopic appearance of the esophageal mucosa and the clinical presentation of the disease.

# Pathophysiology
Pathophysiology of GERD depends on several mechanisms that lead to the retrograde movement of the acidic content of the stomach to the esophagus. These mechanisms include transient lower esophageal sphincter relaxation, hypotensive lower esophageal sphincter, hiatal hernia, and prolongedesophageal acid clearance.

# Causes
Common causes of GERD include obesity, autonomic neuropathy, systemic sclerosis, esophageal achalasia, and hiatus hernia. Other causes of GERD include hypochlorhydria, hypercalcemia, and Zollinger-Ellison syndrome.

# Differentiating Gastroesophageal reflux disease overview from Other Diseases
GERD must be differentiated from other diseases like gastritis, peptic ulcer, crohn's disease, gastric adenocarcinoma, and gastrinoma.

# Epidemiology and Demographics
The prevalence of GERD in USA and Europe ranges from 10,000 to 20,000 per 100,000 people. The incidence of GERD increases with age especially above 40 years.

# Risk Factors
Common risk factors of GERD include smoking, obesity, pregnancy, alcohol binge drinking, and medications like the anticholinergic drugs. Other risk factors include some kinds of food like spicy food and bad eating habits like eating large meals.

# Screening
There is insufficient evidence to recommend routine screening for GERD.

# Natural History, Complications, and Prognosis
If left untreated, 20% of patients with GERD may progress to develop esophageal stricture due to excessive acid in the lower esophagus. Complications of GERD include barrett's esophagus, erosive esophagitis, esophageal ulcer, and esophageal adenocarcinoma. Prognosis of GERD is good with the appropriate treatment.

# Diagnosis

## History and Symptoms
Common symptoms of GERD include heart burn, regurgitation, and dysphagia. A positive history of nausea, vomiting, and regurgitation is suggestive of GERD. Other symptoms of GERD include chest pain, cough, and odynophagia.

## Physical Examination
Patients with GERD usually appear ill due to the pain. Common physical examination include hoarseness of voice, laryngitis, otitis media, and lung wheezes.

## Laboratory Findings
Laboratory findings consistent with diagnosis of GERD is the presence of acidic reflux in the esophagus through the ambulatory reflux monitoring.

## Electrocardiogram
There are no EKG findings associated with GERD. However, EKG can be performed to exclude the cardiac causes of chest pain that can be presented in cases of atypical GERD.

## X ray
X ray imaging suggestive for associated problems with GERD include free acid reflux, esophagitis with scarring, strictures, and barrett's esophagus.

## CT scan
There are no CT findings associated with GERD.

## MRI scan
There are no MRI findings associated with GERD.

## Echocardiography or ultrasound
There are no ultrasound findings associated with GERD.

## Other Imaging Studies
There are no other imaging findings associated with GERD. However, endoscopy may be used in screening for the complications associated with chronic GERD like barrett's esophagus.

## Other Diagnostic Studies
There are no other diagnostic studies associated with GERD.

# Treatment

## Medical Therapy
The mainstay treatment of GERD is lifestyle modifications which include weight loss, elevating head of the bed and no eating before going sleep. The pharmacologic medical therapy is recommended among patients with persistent GERD despite following the lifestyle modifications. Antacids, histamine receptor antagonists, proton pump inhibitors, and prokinetics medications are used in treatment of GERD.

## Surgery
Surgery is not the first-line treatment option for patients with GERD. Surgery is usually reserved for patients with either chronic GERD, high volume of acid reflux, non-compliant medical therapy, the presence of large hiatal hernia, or with upper respiratory manifestations as hoarseness of voice and laryngitis. The nissen fundoplication is the operation of choice in patients with GERD.

## Prevention
Effective measures for the primary prevention of GERD include avoiding food that worsens the symptoms, smoking cessation, weight loss, eating frequent meals, and head raising of the bed while sleeping.