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.

Comparison of Pulmonary Functions at Onset of Ventilatory Insufficiency in Patients With Amyotrophic Lateral Sclerosis, Duchenne Muscular Dystrophy, and Myotonic Muscular Dystrophy

OBJECTIVE: To evaluate pulmonary functions of patients with amyotrophic lateral sclerosis (ALS), Duchenne muscular dystrophy (DMD), and myotonic muscular dystrophy (MMD) at the onset of ventilatory insufficiency. METHODS: This retrospective study included ALS, DMD, and MMD patients with regular outpatient clinic follow-up in the Department of Rehabilitation Medicine at Gangnam Severance Hospital before the application of non-invasive positive pressure ventilation (NIPPV). The patients were enrolled from August 2001 to March 2014. If patients experienced ventilatory insufficiency, they were treated with NIPPV, and their pulmonary functions were subsequently measured. RESULTS: Ninety-four DMD patients, 41 ALS patients, and 21 MMD patients were included in the study. The mean SpO2 was lower in the MMD group than in the other two groups. The mean forced vital capacity (FVC) in the supine position was approximately low to mid 20% on average in DMD and ALS patients, whereas it was 10% higher in MMD patients. ALS patients showed a significantly lower FVC in the supine position than in the sitting position. Maximal insufflation capacity, unassisted peak cough flow, maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP) were significantly higher in MMD group than in the other groups. MEP was significantly the lowest in DMD patients, followed by in ALS, and MMD patients, in order. CONCLUSION: Disease-specific values of pulmonary function, including FVC, MEP, and MIP, can be accurately used to assess the onset of ventilatory insufficiency in patients with ALS, DMD, and MMD.