Neuromuscular disorders and sleep

Neuromuscular disorders are caused by the primary involvement of the motor unit. In these patients, sleep-disordered breathing (SDB) due to respiratory muscle weakness is often encountered during sleep. Because there is a tendency to overlook this disorder, all patients with neuromuscular disorders should be questioned about SDB. Overnight polysomnography is the best investigation for SDB and nocturnal desaturations. In the management of these patients, noninvasive intermittent positive pressure ventilation results in improvement of SDB and breathing.     

Neuromuscular disorders in pregnancy

Many neuromuscular conditions occur more frequently during pregnancy and include carpal tunnel syndrome, Bell's palsy, lumbosacral radiculopathy, meralgia paresthetica, intercostal neuralgia, and other compression neuropathies. Preexisting or coincident neuromuscular diseases, including demyelinating polyneuropathies, inflammatory muscle disease, myasthenia gravis, and inherited nerve and muscle disease present specific problems during pregnancy. We review management of neuromuscular disorders during pregnancy, labor, delivery, and the early postpartum period.     

Neuromuscular disorders in pregnancy

Preexisting and coincident neuromuscular disorders in pregnancy are challenging for clinicians because of the heterogeneity of disease and the limited data in the literature. Many questions arise regarding the effect of disease on the pregnancy, delivery, and newborn in addition to the effect of pregnancy on the course of disease. Each disorder has particular considerations and possible complications. An interdisciplinary team of physicians is essential. This article discusses the most recent literature on neuromuscular disorders in pregnancy including acquired root, plexus, and peripheral nerve lesions; acquired and inherited neuropathies and myopathies; disorders of the neuromuscular junction; and motor neuron diseases.     

Neuromuscular junction disorders mimicking myopathy

Introduction: Small‐amplitude, short‐duration motor unit action potentials are non‐specific findings seen in myopathies and neuromuscular junction (NMJ) disorders. NMJ studies (repetitive nerve stimulation and single‐fiber electromyography) can determine if such findings are related to NMJ abnormalities but are not considered routinely in atypical cases. Methods: Medical records of 338 patients with confirmed NMJ disorders were reviewed to identify cases with a clinical or electrodiagnostic impression of myopathy during initial evaluation. A history of muscle biopsy with findings that did not support a myopathic process was required for inclusion. Results: Four patients met the inclusion criteria. NMJ studies were abnormal in all cases. One patient had elevated acetylcholine receptor antibodies. Three patients were antibody negative: 2 demonstrated immunotherapy responsiveness, and 1 had a Rapsyn mutation. Conclusions: NMJ disorders may mimic myopathies, and NMJ studies should be performed to clarify so‐called “myopathic” electromyographic findings to avoid unnecessary testing and delayed diagnosis. Muscle Nerve 50 : 854–856, 2014