Gastroesophageal Reflux Disease (GERD) is a chronic condition defined by the frequent backflow of stomach contents into the esophagus. It is typically diagnosed when acid reflux occurs more than twice a week, distinguishing it from occasional heartburn. The primary cause is a weakened or improperly functioning Lower Esophageal Sphincter (LES).
The LES is a band of muscle that acts as a valve, closing tightly to prevent stomach acid from flowing back up. When the sphincter is impaired, stomach juices repeatedly irritate the delicate lining of the esophagus. If left untreated, this persistent acid exposure can cause progressive and severe damage.
Structural Damage to the Esophagus
The initial consequence of chronic acid exposure is inflammation of the esophageal lining, known as esophagitis. This inflammation causes the tissue to swell, leading to painful swallowing (dysphagia). Prolonged esophagitis can progress to esophageal ulcers, which are open sores caused by severe erosion of the lining. These ulcers can cause chest pain, nausea, and internal bleeding.
The repeated cycle of tissue damage and healing eventually leads to the formation of scar tissue (fibrosis) within the esophageal walls. This scarring causes the esophagus to narrow, creating an esophageal stricture. Strictures can shrink the food pathway, making it increasingly difficult to swallow solid foods.
Precancerous Cellular Changes
A long-term consequence of chronic, untreated GERD is the development of Barrett’s Esophagus (BE). This condition occurs when the normal protective squamous cells lining the lower esophagus are replaced by columnar cells, similar to the lining of the intestine. This cellular transformation is called intestinal metaplasia and develops as the body attempts to protect the esophagus from chronic acid exposure.
Barrett’s Esophagus is classified as a precancerous condition because these newly formed columnar cells carry an elevated risk of developing dysplasia, meaning the cells have become abnormal. Dysplasia is categorized as low-grade (LGD) or high-grade (HGD), with HGD representing a stage very close to becoming invasive cancer. Individuals diagnosed with BE require regular endoscopic surveillance (EGD) to view the esophagus and check for signs of dysplasia. The goal of monitoring is to detect any progression to HGD or early cancer when it is most treatable.
Elevated Risk of Esophageal Cancer
The primary complication stemming from Barrett’s Esophagus is the development of Esophageal Adenocarcinoma (EAC). Barrett’s Esophagus is recognized as the only known precursor to this specific type of cancer. The presence of BE elevates a person’s lifetime risk of EAC.
The risk of developing EAC increases considerably with the degree of dysplasia, especially high-grade dysplasia. Factors contributing to this heightened risk include a long duration of untreated GERD, advanced age, and obesity. EAC is an aggressive cancer often diagnosed at a late stage because early symptoms, such as trouble swallowing, can be subtle and easily confused with typical GERD symptoms.
Respiratory and Systemic Complications
Untreated GERD can also lead to complications affecting organs outside of the esophagus. One issue is Laryngopharyngeal Reflux (LPR), sometimes called “silent reflux,” which occurs when stomach contents travel up to the throat and vocal cords. LPR can irritate these upper airway structures, leading to chronic symptoms such as a persistent cough, hoarseness, and laryngitis.
Small amounts of reflux material can be aspirated, or inhaled, into the lungs. This aspiration can trigger or worsen respiratory conditions, most notably asthma, and may increase the risk of recurrent pneumonia. Another systemic effect involves the oral cavity, where chronic acid exposure causes dental erosion. The acidity of the stomach contents dissolves the protective tooth enamel, primarily affecting the back surfaces of the teeth.