Sleep apnea, sleep disorders, and hypothyroidism.

The symptoms of hypothyroidism are protean and include apathy, somnolence, lethargy, personality change, and intellectual deterioration. Many of these symptoms may be related to hypothyroid-induced sleep disorders. Hypothyroidism is associated with abnormal ventilatory drive, abnormal sleep architecture, and sleep apnea. Central, obstructive, and mixed patterns of sleep apnea are commonly observed in hypothyroidism. A case of severe sleep apnea in a grossly myxedematous patient who improved dramatically following thyroid replacement alone is presented. Myxedema is a reversible cause of sleep apnea, and thyroid function testing should be considered in its diagnostic work-up.