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A pharyngeal pouch is a pocket that forms in the lining of the pharynx, which sits at the back of the throat between the esophagus and the mouth in humans and most animals. These sorts of pouches are considered a very normal part of embryo development, and are one of the first signs that the mouth, inner ears, and throat are forming properly. In fish, these pouches later develop into gills. When they occur in fully developed children or adults, however, they are often very problematic. Pouches that form later are usually unwanted and unneeded pockets in the mucus lining that coats the throat, and can trap things like food and medication as they’re being swallowed. The condition occurs most often in elderly patients, but can occur at any age, and often requires surgery to resolve.
Embryonic development involves a lot of pouches and pockets as tissues develop into the organs and glands they will become at maturation. Pharyngeal pouches are a fixture in the embryos of most vertebrates, at least at very early stages. Most animals have a series of these pockets surrounding their growing brains that, with time, separate out, grow, and expand into working parts like the throat, the middle ear, and, in fish, gills. With the exception of gills, in most cases whatever develops out of the pouch doesn’t necessarily look like a pouch or sac at all. That’s just the way it starts out, and during development each grows, expands, and stretches to fulfill its intended purpose.
Pouches can also develop along the lining of the developed pharynx, and these are usually somewhat problematic. This condition is frequently also called “Zenker's diverticulum” after a German pathologist named Friedrich Albert von Zenker who is credited with first identifying the aberrations. Zenker suggested in 1877 that the pouch was probably caused by high pressures in the lower pharynx at a weak spot in the mucous coat. People who suffer from this condition often find that they have difficulty swallowing, regurgitate food that they ate some hours ago, and may feel as if they’re choking, particularly during sleep.
In most cases, some of the food that is eaten falls into the pouch when swallowing. Once the pouch is filled up, it extends out into the esophagus. This can make it difficult for food to pass through the esophagus to the stomach. The pouch can increase the risk of choking because food caught in it can fall out, causing a person to choke or spit up food that was eaten hours before. This can especially be a danger at night, because the position of lying down makes it easier for collected food to fall out. Swallowing medicine also can be problematic because pills can get trapped in the pouch, where they're unable to be absorbed and thus can’t possibly do their intended job.
People who have this condition often feel like they’re unable to swallow, and may also make gurgling noises in the throat. On rare occasions, they may also exhibit a lump on the neck, but this usually only happens when the lump is on the outside of the pharynx rather than at the back, which is more common; also, it usually needs to have been growing for some time. The condition most commonly affects Caucasian men over the age of 50. A person may exhibit symptoms for an extended period of time before being formally diagnosed because of the subtle nature of the condition.
A videofluoroscopy swallow study, or barium swallow, is the most effective way of diagnosing a pharyngeal pouch in most cases. In this test, the patient drinks a solution that contains barium sulfate, a metallic compound that is visible on x-rays. A videofluoroscopy test uses a video x-ray to track the path of the barium sulfate through the digestive system, revealing any discrepancies that might exist. The compound usually doesn't leave any lasting symptoms, but drinking plenty of fluids and eating raw fruits and vegetables shortly after the procedure is usually advised to help flush the barium out of the body.
Specific treatments aren’t usually required unless there are significant symptoms or complications, though there are a few things people can do to minimize problems; eating more slowing and chewing food more thoroughly is one, as is drinking plenty of fluids with each meal. Surgery may become necessary if the pouch is posing any real problems, or if any aspirations, ulcerations, or carcinomas are detected. In most cases the condition can be treated with either an endoscopic procedure or open surgery. The endoscopic approach consists of sliding an esophagoscope down the throat and using either staples or a laser to seal the pouch. With open surgery, an incision is made in the neck and the pharyngeal pouch is cut loose and removed from the surrounding tissues.
In rare cases, the condition can result in a carcinoma, or cancerous tumor, in the pharynx, so long-term follow-up appointments are often ordered, especially in younger patients. Health care providers usually like to monitor development and healing, and periodically check to be sure new pouches aren’t forming somewhere else. Proactively treating things as they develop can stop them from becoming bigger problems later on.