[Respiratory form of onset of motor neuron disease]

To present a case of respiratory failure as the form of onset of amyotrophic lateral sclerosis, to review the main clinical findings, data of the investigations done which suggest the presence of this disorder and describe its therapeutic management.

A 68 year old man presented with a subacute illness characterized by a sleep disorder with sleep fragmentation, snoring of increasing intensity, without clear pauses of apnea, progressive diurnal hypersomnia accompanied by progressive dyspnea followed by respiratory failure with respiratory acidosis and difficulty in manipulating things with his hands. Diagnostic investigations showed a restrictive pattern without pulmonary fibrosis, due to paralysis of the diaphragm, and the presence of electromyographic signs compatible with motorneuron disease. The patient was treated with riluzole 100 mg/day and non-invasive mechanical ventilation and maintained an acceptable quality of life.

Motorneuron disease may start with acute or progressive respiratory failure without a clear etiological cause and may appear to be similar to obstructive sleep apnea syndrome. The treatment of choice for this respiratory problem is non-invasive mechanical ventilation. Absence of symptoms of bulbar involvement is essential for a favourable prognosis.