Sleep Disordered Breathing in Duchenne Muscular Dystrophy.

This review aims to explain the inevitable imbalance between respiratory load, drive, and muscular force that occurs in the natural aging of Duchenne muscular dystrophy and that predisposes these patients to sleep disordered breathing (SDB). In DMD, SDB is characterized by oxygen desaturation, apneas, hypercapnia, and hypoventilation during sleep and ultimately develops into respiratory failure during wakefulness. It can be present in all age groups. Young patients risk obstructive apneas because of weight gain, secondary to progressive physical inactivity and prolonged corticosteroid therapy; older patients hypoventilate and desaturate because of respiratory muscle weakness, in particular the diaphragm. These conditions are further exacerbated during REM sleep, the phase of maximal muscle hypotonia during which the diaphragm has to provide most of the ventilation. Evidence is given to the daytime predictors of early symptoms of SDB, important indicators for the proper time to initiate mechanical ventilation.