Heartburn overview

# Overview
Heartburn or pyrosis is a painful or burning sensation in the esophagus, just below the breastbone (sternum)  caused by regurgitation of gastric acid. The pain often rises in the chest and may radiate to the neck, throat, or angle of the jaw. Heartburn is also identified as one of the causes of chronic cough, and may even mimic asthma.
Heartburn main cause is gastroesophageal reflux disease, and it is a symptom of that disorder, but it can also be mistaken with other causes of chest pain, including life-threatening ones such as acute coronary syndromes.

# Historical Perspective
Heartburn was first medically described by Blount in 1656, who called the symptom "Dyspepsy".

# Classification
There is no established system for the classification of heartburn.

# Pathophysiology
The sensation of heartburn is caused by  exposure of the lower esophagus to the acidic contents of the stomach. Normally, the lower esophageal sphincter (LES) separating the stomach from the esophagus is supposed to contract to prevent this situation. If the sphincter relaxes for any reason (as normally occurs during swallowing), stomach contents, mixed with gastric acid, can return into the esophagus. This return is also known as reflux, and may progress to gastroesophageal reflux disease (GERD) if it occurs frequently. If this is the case, the gastric acid and pepsin now located in the esophagus can injure the tight junction proteins in the esophageal epithelium. This results  in increased paracellular permeability and dilated intercellular space and edema in the submucosa, which is amplified by an immunological mechanism mediated by inflammatory cytokines.

# Causes
Heartburn is commonly caused by gastroesophageal reflux disease (GERD) or adverse reactions to various food and drugs, causing esophagitis. 
Life threatening causes of heartburn are far less common and include acute coronary syndromes and esophageal cancer. Very uncommon causes include CREST syndrome and Zollinger Ellison syndrome.

# Differentiating heartburn causes
Heartburn must be differentiated from other diseases that cause chest pain, such as acute coronary syndromes.
Heartburn may also be differentiated from other diseases that cause dysphagia such as esophageal cancer, achalasia and eosinophilic esophagitis in high risk individuals.

# Epidemiology and demographics
Heartburn is a very prevalent symptom in general populations worldwide.

# Heartburn Risk Factors
Common risk factors in the development of heartburn as a consequence of gastroesophageal reflux disease (GERD) are obesity, increasing age, smoking, hiatal hernia, white bread, chocolate, mint, cinnamon, carbonated beverages, fatty foods, alcohol, wine and beer.
Less common risk factors include certain genetic changes.

# Screening
No screening is indicated for heartburn in asymptomatic patients.

# Natural History and Prognosis
Natural history of heartburn depends on its cause.
The most common cause is gastroesophageal reflux disease (GERD) which, 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;
- Esophageal adenocarcinoma.
Prognosis of GERD is good with the appropriate treatment.

# Diagnostic Study of Choice
The diagnosis of heartburn is made based on the patient's history. Diagnostic studies must be performed if patient is at high-risk for Barrett's esophagus or if there are alarm signs. The diagnostic study of choice in such cases is upper endoscopy.

# History and Symptoms
Heartburn per se is a symptom. It may be accompanied by other symptoms such as: regurgitation, and dysphagia. 
A positive history of nausea, vomiting, and regurgitation is suggestive of gastroesophageal reflux disease (GERD). Other symptoms of GERD include chest pain, cough, and odynophagia.

# Physical Examination
Patients with heartburn usually appear uncomfortable, but the symptoms are commonly mild and frequent.
Occasionally the patients may appear ill due to the pain in a emergency department setting. Common physical examination may include hoarseness of voice, laryngitis, otitis media, and lung wheezes.

# Laboratory Findings
There are no laboratory findings associated with heartburn.

# Electrocardiogram
There are no ECG findings associated with heartburn.
The ECG may be useful in the diagnosis of cardiac causes of heartburn such as acute coronary syndromes.

# X-ray
There are no x-ray findings associated with heartburn.
X-ray may be used though, for differential diagnosis such as esophageal strictures or hiatal hernia.

# Echocardiography and Ultrasound
There are no echocardiographic or ultrasonographic findings associated with heartburn as a symptom of gastroesophageal reflux disease (GERD).

# CT-Scan
There are no CT-Scan findings associated with heartburn.

# MRI
There are no MRI findings associated with heartburn.

# Other Imaging Findings
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
Other diagnostic finding present in heartburn and consistent with diagnosis of gastroesophageal reflux disease (GERD) is the presence of acidic reflux in the esophagus through the ambulatory reflux monitoring.
The 12 lead ECG may be used if heartburn due to cardiac causes is suspected.

# Medical Therapy
The treatment of heartburn in the setting 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 hoarsness of voice and laryngitits. The nissen fundoplication is the operation of choice in patients with GERD.

# Primary 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.

# Secondary Prevention
The primary and secondary prevention strategies for heartburn are the same.

# Cost-effectiveness of Therapy
The use of proton pump inhibitors for 8 weeks associated with lifestyle modifications is a cost-saving strategy in patients with heartburn and gastroesophageal reflux disease (GERD).