Chapter 153. Dysphagia, Aspiration and Swallowing Dysfunction

1. What symptoms are consistent with oropharyngeal versus esophageal dysphagia?

2. What etiologies and mechanisms lead to dysphagia?

3. What tests and studies are useful to evaluate dysphagia, based on symptoms and signs?

4. What treatments are available for each etiology of dysphagia?

5. What is the long-term prognosis and follow-up for dysphagia, based on the diagnosis?

Dysphagia is caused either by lack of coordination of the muscles required to transfer food material from the mouth to the stomach or by a fixed obstruction between the mouth and the stomach.

Epidemiology

Dysphagia is a common complaint, especially in the elderly. Fifteen percent of people older than 60 years who live independently complain of dysphagia, whereas 30–60% of residents in institutional settings experience dysphagia. Incidence and prevalence also varies according to underlying neurological problems. Various neurological disorders have increased risk of dysphagia (Table 153-1). Furthermore, dysphagia is associated with high mortality and morbidity. Patients with stroke who have dysphagia are twice as likely to die as patients without dysphagia. Several studies have also demonstrated that patients with dysphagia have higher incidence of aspiration pneumonia, longer length of hospital stay, as well as more severe levels of disability years after their stroke.

Swallowing is divided into three phases: the oral preparatory phase, the pharyngeal phase, and the esophageal phase. Oral preparatory phase starts with the food bolus being placed in the mouth and being chewed with the help of the muscles of mastication. From the oropharynx, the food bolus is propelled by the back of the tongue and other muscles into the pharynx, with voluntary elevation of the soft palate in order to prevent food from entering the nose. The cranial nerves involved in this stage of swallowing include the trigeminal, facial, and hypoglossal nerves.

The pharyngeal phase starts as the bolus reaches the pharynx. Special sensory receptors activate this involuntary phase of swallowing. The reflex, which is mediated by the swallowing center in the medulla, causes the food to be further pushed back into the pharynx and esophagus by rhythmic, involuntary contractions of several muscles in the back of the mouth, pharynx, and esophagus.

The esophageal phase begins with the opening of the upper esophageal sphincter. The lower esophageal sphincter relaxes and food passes into the stomach. The passage of food through the esophagus during this phase requires the coordinated action of ...