Sleep disturbances in dialysis patients.

Sleep disorders are common in dialysis patients. Insomnia is reported in almost 70% of the dialysed. Old age, presence of common sleep disorders, such as sleep apnea syndrome (SAS) and restless legs syndrome (RLS), comorbid clinical conditions, metabolic parameters and characteristics of dialysis, represent the main risk factors for insomnia. RLS is independently associated with uremia, affecting almost 30% of Caucasians dialysed. Pathophysiology of uremic RLS is still unclear. Although the exact pathogenetic mechanism remains unknown, the efficacy of kidney transplantation on RLS symptoms supports the involvement of renal function in this disturbance. SAS affects 30-80% of dialysis patients. The use of neurophysiological measures is necessary to diagnose SAS. This approach is not applicable in all dialysis patients; consequently, validated questionnaires might be useful to screen patients with a high risk of apnea. Risk of obstructive and central respiratory events are increased by renal failure and dialysis therapy. Excessive daytime sleepiness (EDS) is often reported by the dialysed population. Direct effects of uremic encephalopathy and of somnogenic cytokines have been suggested as the cause of EDS, in addition to the sleep disturbances that increase daytime sleepiness by impairing nocturnal sleep efficiency. Although less frequent, the presence of other sleep disturbances (such as nightmares and narcolepsy) should be carefully evaluated in the uremic population. Several sleep disturbances may potentially be treated but, if left untreated, may impair health status and increase the risk of mortality. However, literature and personal data suggest that undertreatment is common, calling to higher awareness of sleep disturbances among nephrologists.