Aphagia is the inability or refusal to swallow. The word is derived from the Ancient Greek prefix α, meaning "not" or "without," and the suffix φαγία, derived from the verb φαγεῖν, meaning "to eat." It is related to dysphagia which is difficulty swallowing, and odynophagia, painful swallowing. Aphagia may be temporary or long term, depending on the affected organ. It is an extreme, life-threatening case of dysphagia. Depending on the cause, untreated dysphagia may develop into aphagia.
Classification
Behavioural aphagia
The following behavioural classifications result from studies performed on rats, in which lesions were made on the lateral hypothalamus region in the brain.
Passive aphagia: An animal with passive aphagia will not respond to food if it is presented. However, if food is inserted into the mouth, the animal will chew.
Active aphagia: Active aphagia is a complete rejection of food. The animal will physically push food away or move its head from it. One might first sample the food by smelling or tasting, then spit out anything in the mouth. Afterwards the animal will show a complete repulsion to the food. The animal reacts to food as if it is bitter or foul.
Mixed aphagia: When presented with food, the animal initially does not react positively or negatively. However, when food is placed in the mouth, the animal demonstrates active aphagia, spitting out the food and refusing to eat thereafter.
These studies point to the function of the hypothalamus in regulating food intake. Animals in this study also demonstrated several other types of eating behaviour: "weak eating," in which the animal slowly approaches, chews, and swallows small observable amounts of food for a brief period; "good eating," in which the animal reaches normally for the food and eats reliably; and "vigorous eating," in which the animal gluttonously reaches for and devours the food. In these cases, there was either minor or no damage to the lateral hypothalamus. Aphagia not classified under behavioral aphagia typically has a structural cause, see [|causes].
Causes
Aphagia is usually the result of many different diseases as well as different medical treatments. The most common causes of aphagia are:
Chemotherapy – radiation from cancer therapy may cause a stricture of the throat leading to the inability to swallow.
Stroke – swallowing problems can cause stroke victims to aspirate food or liquid into the lungs and cause pneumonia mostly in elderly people.
Parkinson's disease – the mechanism of swallowing disorders in Parkinson's disease may be related to extrapyramidal and autonomic system disorders. The cardinal symptoms of Parkinson's disease: tremor, bradykinesia, and rigidity are initially responsible for swallowing, which is mainly observed in the advanced stages of the disease
Damage to the lateral hypothalamus can also lead to aphagia, as seen in the 1978 study by Timothy Schallert and Ian Whishaw.
It is important to note that all these causes are indirect.
Diagnosis
Modified barium swallow – videofluoroscopic swallow. A lateral video X-ray that provides objective information on bolus transport, safest consistency of bolus, and possible head positioning and maneuvers that may facilitate swallow function depending on each individual's anatomy and physiology.
During the treatment of aphagia, it is important to provide adequate nutrition and hydration. If a person is not able to tolerate a regular diet, diet modifications and alternative means of nutrition may be considered. These include thickening liquids or by changing the texture of the solid foods to reduce the required amount of mastication needed or to reduce other symptoms of oral dysphagia. Alternative means of nutrition may also be needed in more severe cases. In these cases, nasogastric or percutaneous endoscopic gastronomy tubes may be placed. Other compensatory measures may include reducing the bolus size or postural strategies. A speech-language pathologist is one professional who evaluates and treats aphagia and dysphagia and can recommend these strategies depending on the etiology of the deficit and the location of the breakdown within the swallowing mechanism. True treatment of aphagia/dysphagia comes from neuromuscular re-education and strengthening/coordination in most cases. This can be achieved by use of pharyngeal strengthening exercises, thermal stimulation of the swallowing trigger and oral motor exercises. In some cases, it is also appropriate to complete therapeutic exercises in conjunction with neuromuscular electrical stimulation which utilizes low-level electrical currents to target muscle fibers from an external source.
