CHICAGO — Restless legs syndrome affects between 5% and 15% of the population and is often manageable, yet it continues to be misdiagnosed and underreported.
Dr. Penny Tenzer told the American Academy of Family Physicians annual scientific conference that a simple mnemonic, URGE (from the words uncomfortable and urge, rest, getting up, and evening), helps identify key RLS symptoms:
▸ An uncomfortable feeling in the legs, accompanied by an urge to move.
▸ Rest or inactivity make it worse.
▸ Getting up and moving makes it better.
▸ Symptoms typically persist in the evening, often making sleeping difficult.
“I ask patients with suspected RLS is, 'do your legs keep you up at night?' That may be the first clue,” she said. If the patient answers “yes” to the rest of the questions, and there's no other apparent reason for the symptoms, then he or she has RLS.
Primary RLS likely is influenced by genetics, especially where onset occurs before the age of 45 years, she noted.
Iron deficiency, pregnancy, end-stage renal disease, peripheral neuropathy, medications, and excessive caffeine consumption may worsen symptoms, said Dr. Tenzer, director of the residency program in the department of family medicine and community health at the University of Miami.
In addition, 85% of RLS patients also have a condition called periodic limb movements of sleep (PLMS), which is marked by spontaneous jerking of a limb. “A finding of PLMS supports a diagnosis of RLS,” she said. Other comorbidities include depression, anxiety, neuropathy, narcolepsy, and apnea.
“The last supporting criterion is to give the patient a test dose of dopamine, which eases RLS symptoms,” she advised.
RLS pathophysiology relates to dopa- minergic dysfunction and iron use and storage, and decreases in iron concentration in the substantia nigra and the putamen correlate with RLS severity. “After the URGE questions, check the patient for ferritin saturation. A ferritin [reading] under 40 mcg/L may be indicative and below 20 mcg/L definitely indicative that treatment is needed.”
Before beginning pharmacotherapy, one should advise lifestyle changes such as reducing or eliminating caffeine and alcohol intake and exercising. Even mental tasks, such as doing a crossword puzzle, help.
Dopaminergic agonists, which include pramipexole and ropinerole, are the sole FDA-approved class of drugs for the treatment of primary RLS. Another option is the dopamine precursor, levadopa. Sedative-hypnotic agents often are prescribed, and patients with painful RLS may be given an anticonvulsant or opioid, she noted.
“[Dopaminergic] agonist therapy can be started in those whose symptoms occur more than twice a week. Dosages are lower than those used in Parkinson's disease. If symptoms occur less often and sleep is a problem, consider using an opioid or gabapentin as a third line, though usually two successive dopamine agonists are used.”
Dopaminergic agents require titration, and decisions to use these agents for RLS should not be based solely on the treating physician's experience with Parkinson's, which is a different disease, she cautioned.
In patients whose RLS occurs nightly, Dr. Tenzer advised avoiding levadopa-carbidopa therapy because long-term use of these drugs can produce a worsening of symptoms and symptom rebound.
Dr. Tenzer is on the speakers' bureau for Boehringer Ingelheim, which manufactures and markets Mirapex (pramipexole).