The structure of the esophagus:
The esophagus is a muscular tube of about 25 cm in length. It is lined by the non-keratinized stratified squamous epithelium, which abruptly changes to gastric epithelium at the gastroesophageal junction. The stomach is a very acidic environment that has special types of cells that are specially adapted to an acidic environment but the esophagus is not adapted to this. At the end of the esophageal tube, there is a sphincter known as the lower esophageal sphincter that prevents acid from entering the esophagus. When you eat, the food is carried down the esophagus by successive waves of peristalsis. When a peristaltic wave enters the lower esophagus, the lower esophageal tube sphincter relaxes permitting the food to enter the stomach.
Typically, small amounts of acid does get into you esophagus several times during the day. However, this amount is so minute that it usually does not cause any harm. You develop symptoms when there is prolonged exposure of the esophageal mucosa to the acidic contents.
This can be due to 2 reasons:
- Excessive reflux – Increased number of episodes of reflux and increased volume resulting in incompetence of the lower esophageal sphincter.
- Normal mechanism for cleansing the lower esophagus is lost.
Barrett’s esophagus is a precancerous lesion usually developed from the prolonged exposure of the esophageal epithelium to the acidic contents of your stomach. This most commonly occurs among white males. Not everyone with acid reflux develops Barrett’s esophagus and not everyone with Barrett’s esophagus will go on to develop cancer of the esophagus.
The normal lining epithelium of the esophagus is squamous and the lining epithelium of the stomach is glandular mucosa. When there is prolonged exposure of the esophagus to acid, the squamous epithelium of the esophagus slowly changes to glandular epithelium. This is known as metaplasia of the esophageal mucosa. Barrett’s esophagus is the presence of glandular mucosa in the esophagus.
This is a precancerous lesion from which an adenocarcinoma of the lower esophagus can develop. However, most individuals with Barrett’s esophagus do not develop esophageal tumors. Only about 5% to 10% of the population with Barrett’s esophagus develops adenocarcinoma. This group of people undergoes progressive changes of the lining mucosa, known as dysplastic changes.
As a result, people with Barrett’s esophagus are investigated every year or so to detect any dysplastic changes. They are advised to undergo regular endoscopy and biopsy procedures to detect any changes. If any changes are detected, it is an early indication for a prophylactic removal of the lower esophagus (esophageal resection).
How is Barrett’s esophagus diagnosed?
Barrett’s esophagus does not have any specific sign and symptoms but most of them will have symptoms of acid reflux. Since there are no specific symptoms of Barrett’s esophagus, it is diagnosed by an upper GI endoscopy and biopsy.
An endoscopy is carried out by a gastroenterologist. A long flexible tube with a camera attached to it at the end will be inserted through your mouth. You will be given sedatives before this procedure to make it less painful. However, it will be a little uncomfortable. With this, your doctor will be able to visualize the inside of your esophagus and inspect the lining epithelium. After inspection, at the end of the procedure before taking the tube out, the doctor will remove a small piece of the tissue and send it for histology. A histological report will help to confirm the diagnosis of Barrett’s esophagus.
- Normally, small amounts of acid does get into your esophagus several times during the day. However, this amount is so minute that it usually does not cause any harm.
- Barrett’s esophagus is a precancerous lesion usually developed from the prolonged exposure of the esophageal epithelium to the acidic contents of your stomach.
- Most individuals with Barrett’s esophagus do not develop esophageal tumors.