Sleep Problems & Kidney Failure

A small study in the Aug. 15 issue of the Journal of Clinical Sleep Medicine examined the sleep quality of people with both kidney failure and obstructive sleep apnea.

The study involved 30 adults with moderate to severe OSA; 12 of them had kidney failure – also called end-stage renal disease. The other 18 people had normal kidney function.

Results show that people with normal kidney function slept for about 5.5 hours during an overnight sleep study; but people with kidney failure slept for only 4.4 hours.

Why was their sleep so disrupted? In large part it was because of frequent periodic limb movements.

People with kidney failure had about 31 PLM per hour of sleep; these movements caused almost 15 arousals per hour. In contrast, people with normal kidney function had only one arousal per hour caused by PLM.

The authors report that OSA is extremely common in people with kidney failure. But sleep disruptions tend to persist even after treating OSA with CPAP therapy.

The study shows that PLM may contribute to the problem; the authors conclude that treating PLM may improve sleep quality in people with OSA and kidney failure.

The AASM reports that PLM involve simple, repetitive muscle movements. Usually a lower-leg muscle tightens or flexes. A typical movement is for the big toe to extend. Often the ankle, knee or hip also will bend slightly. People with PLM often have restless legs syndrome too. Medications can treat both PLM and RLS.

Kidney failure commonly is treated by hemodialysis. Blood is drawn from the body, cleaned and pumped back into the body. In May the Sleep Education Blog reported that some dialysis clinics now offer to perform the treatment while patients sleep.

A Hormonal Link Between Restless Legs & Pregnancy

A new study in the journal Sleep links restless legs syndrome in pregnant women to the hormone estradiol.

Results show that in the last trimester, pregnant women with RLS have much higher levels of estradiol than healthy controls. Estradiol is an estrogenic steroid hormone.

RLS is more common in women than in men. Symptoms often appear for the first time during pregnancy. These symptoms tend to worsen during pregnancy. Then they may improve or even disappear after delivery. The risk of developing RLS increases gradually with each pregnancy.

RLS is a sleep-related movement disorder. It involves an almost irresistible urge to move the legs at night. This urge tends to occur along with unusual feelings or sensations deep in the legs. These uncomfortable sensations often are described as a burning, tingling, prickling or jittery feeling.

RLS can severely disturb a person’s ability to sleep. Eighty percent to 90 percent of people with RLS also have periodic limb movements during sleep. These are involuntary jerking or twitching movements of the feet or legs.

Disturbed sleep is common during pregnancy. In addition to RLS, pregnant women may experience problems such as snoring and leg cramps.

Learn more about sleep and pregnancy here.