Management of neurogenic dysphagia

Dysphagia is common in patients with neurological disorders. It may result from lesions in the central or peripheral nervous system as well as from diseases of muscle and disorders of the neuromuscular junction. Drugs that are commonly used in the management of neurological conditions may also precipitate or aggravate swallowing difficulties in some patients. Neurogenic dysphagia often results in serious complications, including pulmonary aspiration, dehydration, and malnutrition. These complications are usually preventable if the dysphagia is recognised early and managed appropriately. The act of swallowing may be viewed as three discrete but inter-related physiological stages: the oral, pharyngeal, and oesophageal phases. The oral phase is initiated voluntarily and serves to prepare the food bolus and deliver it to the pharynx. An adequately prepared and sufficiently large and cohesive food bolus triggers the swallow reflex by stimulating the sensory receptive field in the soft palate, dorsum of the tongue, epiglottis, and posterior pharyngeal wall. Simultaneously the larynx closes and the velum retracts upwards to prevent the entry of food and fluid into the nasal cavity. Coordination of respiration and swallowing is necessary to prevent the penetration of food into the airways. This is achieved by transient cessation of breathing, a process known as deglutition apnoea. The pharyngeal phase is followed by a prolonged expiration to avert mist aspiration, that is inhalation of air held in the pharynx (which is usually saturated with fluid and food particles). The swallow reflex triggers the oesophageal peristaltic movements and causes relaxation of the circopharyngeal sphincter. This, combined with the effects of gravity, facilitates the transmission of food down into the stomach. Several factors contribute to the swallowing difficulties encountered in patients with neurogenic dysphagia. These include weakness of the oral musculature and tongue movements, failure to form a cohesive food bolus, reduced sensitivity of the …