What do you mean by Barrett's esophagus?
Norman Barrett (1903–1979), a British surgeon at St Thomas' Hospital, first described specified changes in the appearance of the esophageal lining of patients with acid reflux disease in 1950. These changes are in the form of abnormal pink projections extending upwards into the esophagus from the stomach. They represent replacement of the normal cells lining the esophagus with another type of cells peculiar to the stomach or the intestine.
When the stomach contents reflux into the esophagus, its cellular lining is eroded. This damage mainly affects the superficial cells and the deep or basal germinative cells (stem cells) usually survive. In these cells a genetic switch causes them to generate new cells of specialized characteristics that differ from native esophageal cells. The new cells produce mucus and are more resistant to acid. They also differ in shape, being columnar instead of the spindle shaped esophageal cells. They also have some cells which are goblet shaped and are stuffed with mucus. This cellular pattern is similar to intestinal cells and is diagnostic of Barrett's esophagus.
About 10% of patients with acid reflux disease have Barrett's esophagus. It's usually diagnosed during endoscopy and has specific features.
The pink projections characteristic of Barrett's esophagus vary in length, some are short (less than 3cm) and others long (more than 3cm) having higher risk of developing intestinal metaplasia . Proper diagnosis is confirmed by taking a specimen of this abnormal tissue and examining it under the microscope.
The process of replacement of esophageal cells with intestinal tissue (transformation of native cellular pattern with normal tissue of another organ) is called Metaplasia.
Metaplasia usually progresses into Dysplasia, a change in individual cellular features. Abnormalities involve cellular architecture, intracellular infrastructure and nuclei. Cells usually vary in size and shape and their nuclei reveal profound changes. Dysplasia may be low-grade or high-grade and this variety is pre-cancerous, usually complicated with a type of cancer called Adenocarcinoma of the esophagus. About 10% of patients with Metaplasia change into Dysplasia, and 1% of patients with Barrett's esophagus will have the risk of developing cancer.
As Barrett-type intestinal metaplastic cells are under-developed, they don't have normal sensory nerve supply and patients used to suffer from heartburn may not experience it any more. Accordingly, sufferers reporting spontaneous relief of symptoms after a long standing heartburn should be managed with a high index of suspicion.
In Barrett's esophagus It's mandatory to monitor cellular changes frequently. If no Dysplasia is associated endoscopy should be performed every year. When Dysplasia is detected, the opinion of an experienced pathologist is essential to confirm the diagnosis and differentiate between low-grade and high-grade types. In low-grade Dysplasia endoscopy should be repeated every six months to detect any progression. In high-grade Dysplasia, if the patient is at high risk for surgery, endoscopic ablative procedures should be considered. In fit patients surgical excision of the esophagus is the preferred approach, the operation is called esophagectomy.
Photo-dynamic therapy is an endoscopic ablative procedure which involves injecting a photo-sensitizing material followed by delivering red laser light to sensitized cells. Consequently, cells containing the drug are destroyed.
Endoscopic mucosal resection is safer than surgery and involves excision of dysplastic tissue, it also has a diagnostic role as it submits an adequate specimen for proper diagnosis and determining the depth of invasion.
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