Pharyngeal pouch

A pharyngeal pouch is a pocket that balloons out the back of the pharynx or throat. It collects food and the patient becomes aware of a residue of food in the throat after swallowing. As it enlarges over months/years it collects more of each swallow. This produces an unpleasant sensation of having something stuck in the throat. Often food is brought up again hours after eating it. With time more food is trapped than is swallowed and the patient can begin to lose weight. Eating out can be embarrassing. Frequently coughing occurs after eating but this generally does not deliver the food out of the pouch. In extreme cases food trapped in the pouch can spill over into the windpipe (trachea) and cause chest infections.

Pharyngeal pouches usually present in people over 50 but occasionally can occur earlier. They generally develop because of an incoordination of the swallowing mechanism.

normal swallow

Usually when we swallow food, there is an automatic process that begins at the back of the tongue and progressively travels down the throat (pharynx) and gullet (oesophagus) into the stomach. This process is a sequential wave of relaxation followed by contraction creating a travelling "squeeze" that pushes the food before it down the food passage. Relaxation of the food passage muscles before the "squeeze" wave accommodates the food bolus which essentially travels down within the travelling wave of relaxed muscles.

why do pouches develop?

A pouch develops because there is an incoordination between the squeeze wave and the preceeding wave of relaxation. The squeeze wave ends up forcing the food bolus into an area that has not relaxed in anticipation of the food. This area is at the site of the upper oesophageal sphincter otherwise known as the cricopharyngeus muscle. Why the cricopharyngeus does not relax in time for the food bolus is not always clear but it is often associated with gastro-esophageal reflux whereby acid from the stomach comes up into the throat causing a reflex constriction of the muscle. Also, as part of the aging process there can be a generalised incoordination right down the swallowing passage but most evident in the throat.

When the food bolus comes up against the constricted cricopharyngeus there is a bulging of the pharyngeal wall at its weakest point which is the back wall just above the cricopharyngeus. This area is known as "Killian's dehiscence" after the man who described it and is relatively weaker than other areas purley because it doesn't have as many muscle layers. So the back wall gets stretched with each swallow until there is a pocket or pouch which hangs down behind the oesophagus and which collects food easily (as it doesn't have a good muscle layer unlike the main channel). The build up of food after each swallow is uncomfortable and increasingly embarrasing.

diagnosis

A pharyngeal pouch is diagnosed from the history and a barium or videoswallow. The classic story is of food getting trapped in the throat after swallowing and of undigested food being brought up hours later. The diagnosis is clinched by a test whereby liquid barium is swallowed while video XRays are taken demonstrating the pouch ballooning out the back of the pharynx.

Pharyngeal pouch surgery

Surgery is advised when a pharyngeal pouch is diagnosed as it will increasingly become the preferred food channel and cause increasing difficulty in swallowing.  Learn more about the surgery...