Essential criteria for clinical diagnosis of restless legs syndrome

Jul 21 2011

We've all experienced abnormal sensations in our legs at one time or another, but for as many as 10 percent of the US population, restless legs syndrome (RLS) is a daily occurrence. Characterized by throbbing, pulling, tingling, itching, and crawling sensations, RLS is a neurological disorder that produces unpleasant physical sensations in the extremities and an urge to counteract that sensation by movement.

RLS occurs in both men and women, but according to statistics from the National Institutes of Health, "the incidence is about twice as high in women." The prevalence of RLS in the general population is higher than most people realize.

"The condition is more prevalent among women," said Bjorn Backe, MD, PhD, Professor of Maternity Care in Trondheim, Norway who has studied RLS among pregnant women. "Pregnancy is an important cause of RLS, but the etiology, that is the mechanism through which pregnancy leads to RLS, remains completely unknown."

In fact, the cause of RLS can be elusive in the general population as well. The primary form occurs for unknown reasons, but according to research studies there may be an underlying genetic factor to the disease.

The secondary form of RLS is the result of a medical condition or side effect from a medication (most often antidepressants, anticonvulsants, and beta blockers). Conditions linked to secondary RLS include: iron-deficiency anemia, peripheral neuropathy (damage to the nerves of the extremities, often due to diabetes), thyroid conditions, kidney failure, vitamin deficiencies, fibromyalgia and varicose veins.

"Varicose veins are an often overlooked and potentially curable cause of restless legs syndrome," said Erez Salik, MD, Co-director of the Greenwich Vein Center in Greenwich, Conn. "For these patients, treating the varicosities can significantly improve the RLS-related symptoms."

Many patients suffer from the symptoms of RLS without realizing anything is wrong. According to David Rye, MD, PhD, Professor of Neurology at Emory University, "the clinical diagnosis is based on four essential criteria."

These include:
•A strong urge to move your legs. Often, but not always, this urge occurs in conjunction with unpleasant feelings in your legs. When the disorder is severe, you may also have the urge to move your arms.

•Symptoms that begin or get worse when you're inactive. The urge to move increases when you're sitting still or lying down and resting.

•Relief from moving. Movement, especially walking, helps relieve the unpleasant feelings.

•Symptoms that start or get worse in the evening or at night.

"There are supportive criteria as well," said Rye, "which include a first-degree family member, periodic leg movements in sleep (present in >90% of subjects); and a good response to medications that mimic the brain chemical dopamine."

To diagnose RLS, doctors often focus on the patient's description of symptoms to ensure they meet the four essential criteria. A neurological and physical exam is often performed and a thorough history should be taken, including: personal and family history, current medications, and sleep habits. Lab tests are frequently performed to rule out other conditions and identify potential vitamin and mineral deficiencies, which may initially present as RLS.

Treatment can vary from person to person and often focuses on relieving the symptoms that a patient is experiencing. If an underlying condition or medication side effect is responsible, then these issues need to be addressed foremost. Supplements to correct deficiencies can help alleviate symptoms for some patients, and in others a variety of medications including dopaminergic medications, benzodiazepines, opioids and anti-convulsants can help treat this uncomfortable disease.

There is some evidence that RLS may be related to abnormalities in neurotransmitters, or brain chemicals including dopamine, which help control gross motor movement. Research is still being conducted to further examine this relationship.

With more research and greater attention, a cure for RLS may be discovered, allowing millions of restless women to rest easy.