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Central sleep
apnea is a heterogeneous group of conditions characterized by changes
in ventilatory drive without airway obstruction; most of these conditions
cause asymptomatic changes in breathing pattern during sleep.
Etiology
Patients with central sleep apnea (CSA) fall into 2 categories. One group presents with hypercapnia with decreased ventilatory drive. Causes include hypothyroidism and central lesions, such as brain stem infarctions, encephalitis, and Arnold-Chiari malformation. This type of central sleep apnea may also complicate neuromuscular diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis, postpolio syndrome) and chest wall abnormalities (notably, kyphoscoliosis). The other group presents with eucapnia or hypocapnia with increased ventilatory drive but with sleep-induced apnea, periodic breathing, or both. Cheyne-Stokes breathing is a discrete pattern of this form of CSA thought to be caused by delays in circulation time that, in turn, cause a lag in recognition by respiratory centers of acidosis, hypoxia, or both (causing hyperpnea) and of alkalosis, hypocapnia, or both (causing apnea). High altitude is another cause of recurrent CSA presenting with hypocapnia. Use of opioids can cause either hypercapneic or hypocapneic CSA.
Congenital central hypoventilation (a form of Ondine's curse) is a rare form of idiopathic CSA in neonates and may be associated with Hirschsprung's disease. A mutation in the PHOX2 gene is responsible for 80 to 90% of cases. This mutation produces variable phenotypes, and clinically evident cases are inherited in a dominant pattern.
Symptoms
CSA is usually asymptomatic and is detected by caretakers or bed partners who notice long respiratory pauses, shallow breaths, or restless sleep. Patients with hypercapnic forms may experience daytime somnolence, lethargy, and morning headache.
Diagnosis
Diagnosis is suspected on the basis of history and confirmed by polysomnography. However, testing may not be necessary if CSA causes no symptoms or is clearly related to an identifiable disorder. To diagnose causes of CSA, brain or brain stem imaging may be indicated.
Treatment
Primary treatment is optimal management of underlying conditions and avoidance of opioids and other sedatives. Secondary treatment of symptomatic patients can be a trial of supplemental O2 or, in patients with hypercapnic CSA who have symptoms despite other treatments, noninvasive continuous or bi-level positive airway pressure. Acetazolamide is effective in CSA caused by high altitude. Phrenic nerve pacing is an option for children > 2 yr with congenital central hypoventilation syndrome.
Last full review/revision November 2007 by Kingman P. Strohl, MD
Content last modified November 2007
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