Symptomatic treatment of respiratory and nutritional failure in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by death of upper and lower motor neurones. Nutritional and respiratory failure occurs in most patients with ALS. Nutritional failure occurs primarily as a result of dysphagia, although malnutrition may also develop in the absence of clinically apparent dysphagia. The optimal management of nutrition in early ALS has not been established. In later stages of the disease, parenteral nutritional support using percutaneous endoscopic gastrostomy confers a significant survival benefit in selected patients. Respiratory failure occurs as a result of bulbar, cervical and thoracic loss of motor neurones. Inspiratory muscles are preferentially affected. Management of respiratory failure includes the use of strategies that limit aspiration pneumonia, the reduction in secretions, and positioning of the patient to a maximal mechanical advantage. Use of non-invasive positive pressure ventilation in appropriate patients significantly enhances survival. The decision to undertake invasive mechanical ventilation should be made prior to the development of symptoms that might warrant this intervention. The progressive nature of the condition should be taken into account when such a decision is discussed with the patient and carer. Further studies are required to determine the optimal nutritional requirements of patients with ALS, and to elucidate the physiological changes involved in the decline in respiratory function.