CONGENITAL CENTRAL HYPOVENTILATION SYNDROME (CCHS) OBSTRUCTIVE SLEEP APNEA

IDIOPATHIC HYPOVENTILATION CONGENITAL CENTRAL HYPOVENTILATION SYNDROME (CCHS)

Disorders of sleep fragmentation include sleep apnea, periodic limb movements (PLMs), and other causes, such as pain and medications. Periodic Limb Movement Disorder (PLMD) is characterized by intermittent movements of the extremities during sleep, which may be associated with arousals from sleep. The most typical movements include extension of the hallux or dorsiflexion of the foot at the ankle. The diagnosis of PLMD requires a full night PSG study demonstrating characteristic limb movements in the anterior tibialis EMG. The severity of PLMD is determined by the number of PLMs and the proportion of movements that cause arousals. There is high night-to-night variability in PLMs; therefore, when PLMD is clinically strongly suspected and PSG does not reveal PLMs, a second diagnostic night may be indicated. Associated with PLMD, restless legs syndrome (RLS) is a disorder characterized by unpleasant sensations in the legs and an urge to move when at rest in an effort to relieve these feelings. RLS sensations are often described by people as aching, burning, or like insects crawling inside the legs. Although 80% of patients who have RLS have PLMD, RLS commonly presents with insomnia rather than sleep fragmentation. Medications that can cause sleep fragmentation include SSRIs.

Sleep-related breathing disorders are a heterogeneous group of conditions (Table 3) that may be associated with alterations in the structure of sleep, in sleep quality, and in gas exchange during sleep. Obstructive Sleep Apnea represents the most frequent cause of sleep-related breathing disorders, which encompass a diversity of conditions that either complicate coexisting disease or present as primary disorders. Many of these disorders have consequences during both sleep and wakefulness and may produce substantial burden of symptoms and disease in untreated individuals.

Table 3. Current terminology for common sleep-related breathing disorders: Primary central apnea Central sleep apnea due to Cheyne–Stokes breathing pattern high-altitude periodic breathing medical condition not Cheyne–Stokes drug or substanceM Primary sleep apnea of infancy Obstructive sleep apnea Sleep-related nonobstructive alveolar hypoventilation, idiopathic Congenital central alveolar hypoventilation syndrome Sleep-related hypoventilation/hypoxemia due to lower airways obstruction neuromuscular and chest wall disorders pulmonary parenchymal or vascular pathology Sleep apnea/sleep-related breathing disorder, unspecified