Sleep disorders. (December 2018) - Tonkin, James
Abstract: Obstructive sleep apnoea–hypopnoea syndrome (OSAHS), obesity hypoventilation syndrome (OHS), periodic limb movement disorder and narcolepsy are the sleep disorders most commonly encountered in clinical practice. All four are characterized by sleep disturbance leading to daytime hypersomnolence. In OSAHS, repetitive partial or complete upper airway obstruction leads to respiratory effort-related arousals and sleep fragmentation. Weight loss can lead to resolution of symptoms. The mainstay of treatment is continuous positive airway pressure (CPAP). CPAP maintains airway patency by delivering a constant positive end-expiratory pressure. OHS occurs in obese patients and causes nocturnal alveolar hypoventilation. Patients have daytime hypercapnia (PaCO2 > 6 kPa) and hypoxaemia (PaO2 < 9 kPa). Some patients can be treated with CPAP, but those who do not respond require bi-level positive airway pressure. Periodic limb movements of sleep is a condition in which repetitive movements of the legs or arms worsen at night. Narcolepsy is characterized by hypersomnolence, cataplexy, sleep paralysis and hypnogogic hallucinations. Patients with narcolepsy should be referred to specialized sleep centres for full polysomnography and management.