Swallowing is a highly complex process that begins with the introduction of food or liquids into the mouth and proceeds to the stomach. Normal swallowing requires nerves, muscles, and the soft tissues of the mouth and throat working together in a coordinated fashion. Swallowing may be divided into three basic phases:
- Oral/preparatory phase (occurs in the mouth): involves chewing (mastication), mixing of food with saliva, movement of the food into the throat (oropharynx)
- Pharyngeal phase (occurs in the throat): This phase normally takes less than 1 second. Food moves from the back of the mouth into the esophagus (the tube that connects the throat to the stomach). The back of the nose (nasopharynx) must be closed to prevent leakage forward into the nose. The voice box (larynx) closes over the windpipe (trachea) to prevent food/liquid from going into the airway.
- Esophageal phase (occurs between the throat and the stomach): Food is pushed from the throat (pharynx) to the stomach via mostly involuntary muscle movements called peristalsis.
Dysphagia (Trouble Swallowing)
Disruption of any portion of this process can result in difficulty with swallowing, known as dysphagia. Dysphagia may manifest in many ways. Some patients have a sensation of things being “stuck” in the throat or chest. Other patients have odynophagia (pain with swallowing), regurgitation (food/liquid “backing up”), aspiration (“things go down the wrong pipe”), heartburn or burning in throat, coughing or gagging with swallowing, hoarseness, weight loss, or other symptoms. Occasional dysphagia is common and is often a result of eating too quickly or not chewing food well enough. Causes of dysphagia are numerous and range from muscle weakness associated with aging to very serious and life-threatening problems such as cancer of the throat. Persistent dysphagia should be evaluated thoroughly.
A complete examination of the mouth and throat that includes the voice box (larynx) and lower throat (hypopharynx) is an essential part of the evaluation of dysphagia. Physical examination may reveal, or at least suggest, the cause of the trouble swallowing. Direct examination of the lining of the esophagus may be necessary. This can now be performed in the clinic on an awake patient (no need for sedation) using transnasal esophagoscopy.
In this procedure, a thin endoscopic camera is passed through the nose and throat, into the esophagus, and all the way to the stomach. Further evaluation with other tests may also be used.
A barium swallow involves swallowing food and liquid along with barium that can be seen on x-ray and taking a series of x-rays of the mouth, throat, esophagus, and stomach. This is often done with a speech pathologist who can evaluate swallowing function face to face at the same time the x-rays are being taken.
Esophageal manometry allows measurement of the pressures generated by muscle contractions in the esophagus. pH measurements may be taken within the throat and esophagus to test the level of acid.
With all these tools, a thorough evaluation of swallowing function and what may cause problems with that function can be performed. Our multidisciplinary approach to dysphagia involves the primary care provider, otolaryngologist, speech pathologist, gastroenterologist, and sometimes, general surgeon.
Mona M. Abaza MD, MS
Matthew S. Clary MD