One way for otolaryngologists to determine the potential for RLS and PLMD is to look more comprehensively at the information they obtain from a sleep study conducted on a patient with suspected sleep apnea. Although RLS is determined only by clinical history (see “Diagnosing Restless Legs Syndrom, left), periodic limb movements (PLM) are diagnosed using sleep studies. According to Dr. Shangold, 85 percent of patients with RLS will show PLM in a sleep study, whereas a much smaller percentage of patients with PLM detected on a sleep study will have RSL as determined by history. “In my mind, PLMD is the motor manifestation of RLS, and RLS is the sensory component,” said Dr. Shangold.
Explore this issue:December 2012
Dr. Shangold, who taught an instructional course on sleep studies with Dr. Wardrop at September’s annual AAO-HNS meeting in Washington, D.C., emphasized that many physicians only look at the apnea-hypopnea and respiratory disturbance indices on a sleep study. “There is so much more information on a sleep study, including periodic limb movement,” he said, adding that although periodic limb movements during sleep are quite common, PLMD is quite rare. The disorder is diagnosed if the limb movements at night are contributing to excessive daytime sleepiness and there are no other causes, he said.
“If you see a significant number of limb movements on a sleep study and you don’t have a root cause for excessive daytime sleepiness, that is when the light bulb goes on,” he said. Additionally, he said, the treatment of PLMD is similar to that of RLS.
Dr. Allan also recommends that otolaryngologists look for RLS symptoms, noting that RLS occurs in a reasonable number of sleep apnea patients and in a very high number of patients with chronic obstructive pulmonary disease. He emphasized that treatment of RLS symptoms in sleep apnea patients may be necessary to help their patients sleep well at night. “Current approved medications for RLS are not known to increase sleep apnea and have been used with sleep apnea patients,” he said, but added that opioids, which are sometimes used, may exacerbate sleep apnea.