Motor Neuron Disease Presenting With Acute Respiratory Failure: A Case Study.

Motor neuron diseases (MNDs) refer to a heterogeneous group of progressive neurologic disorders caused by degeneration of motor neurons. The diseases affect either the upper motor neurons, lower motor neurons, or both, and are characterized by weakness, atrophy, fasciculation, spasticity, and respiratory failure. We report a case of a 61-year-old male patient with no past history of cardiovascular or pulmonary disease, who presented with only dyspnea, and no indication of any other symptom such as muscle weakness, atrophy, or bulbar dysfunction. Neuromuscular conduction study, including a study of the phrenic nerve, confirmed the diagnosis of MND. The patient greatly improved giving respiratory assistance at night, using a noninvasive ventilator. This case indicates that MNDs should be considered as differential diagnoses for patients showing acute respiratory failure of unknown causes. This report will aid in the prompt diagnosis and treatment of MNDs.