Resolution of severe obstructive sleep apnea after treatment of anti-muscle kinase receptor-positive myasthenia gravis despite 60-pound weight gain.

Obstructive sleep apnea (OSA) in patients with myasthenia gravis (MG) may be caused by reduced pharyngeal dilator muscle activity. We report a patient with anti-muscle kinase receptor MG with severe OSA and hypoventilation that resolved upon successful treatment of MG despite a 60-lb weight gain.

Obstructive sleep apnea: an unexpected cause of insulin resistance and diabetes.

Obstructive sleep apnea (OSA) is prevalent with type 2 diabetes. Conversely, nondiabetic patients with OSA are at increased risk of developing insulin resistance and diabetes. These disorders independently contribute to increased cardiovascular and cerebrovascular morbidity and mortality. The pathophysiology of OSA may help explain these associations. Evidence demonstrates that treatment of OSA with continuous positive airway pressure may lead to improvement in insulin sensitivity, hemoglobin A1c, systemic hypertension, and other components of the metabolic syndrome. Recognizing and treating OSA in patients with insulin resistance or diabetes ameliorates OSA-related symptoms and improves cardiometabolic risk.

Distribution and course of cortico-respiratory projections for voluntary activation in man. A transcranial magnetic stimulation study in healthy subjects and patients with cerebral ischemia.

The function and course of the cortico-respiratory projections in man are not yet well established. In 30 normal volunteers respiratory muscles were activated by magnetic stimulation of the motor cortex and the cervical and thoracic spinal roots with bilateral recordings from the respiratory muscles. Following cortical stimulation contralateral responses were obtained in all subjects during voluntary inspiration showing a mean latency and amplitude of 13.4+/-1.4ms/1.6+/-1.2 mV (stimulation of the left hemisphere) and 13.2+/-1.3ms/2.5+/-2.5 mV (stimulation of the right hemisphere). Ipsilateral responses were obtained in only 18 (right side) and 21 (left side) subjects and had a significantly (p < 0.001) longer mean latency and lower mean amplitude than the contralateral responses. In 31 patients with impairment of the cortico-respiratory projections due to cerebral infarction demonstrated by magnetic resonance imaging studies, the responsible lesion topography was analysed. We found that, 1. the voluntary activation of respiratory muscles is mediated predominantly by the contralateral motor cortex, 2. the descending cortico-respiratory projections are located within the pyramidal tract, and 3. the cortico-respiratory projections to the respiratory muscles are frequently affected in patients with hemiparesis due to acute stroke. These findings might explain the increased incidence of pneumonia at the hemiparetic side in patients with cerebral ischemia as shown in previous studies.