PROBLEM A 42-year-old woman presents to the clinic complaining of fatigue for the past month. She denies heart palpitations, shortness of breath, pain, or changes in appetite or weight. Further questioning reveals that she has trouble sleeping; she often tosses and turns in bed. She also describes a crawling sensation in both legs, which only occurs in the evenings and improves with activity.

The patient is happily married and works as a librarian. She has been smoking 1 pack of cigarettes per day for the past 20 years. She denies alcohol or drug use and does not take any medications. On physical examination, the patient is a well-dressed female who appears her stated age. She has a normal body mass index and her BP is 118/70 mm Hg. The physical and neurologic exams are within normal limits.

TABLE 1 Diagnosis of RLS

APPROACH Restless legs syndrome (RLS) is a neurologic movement disorder first described in the mid-1940s by Swedish neurologist Karl A. Ekborn. The disorder is characterized by motor restlessness and unpleasant sensations (usually in the legs) that occur at rest. In most patients, limb movements are noted during sleep. These periodic jerking movements of the ankle, knee, and hip are seen on polysomnographic testing. Patients with RLS often have sleep disturbances and difficulty describing their symptoms. The essential criteria for the diagnosis of RLS are listed in Table 1.

About 10% to 15% of the US population is affected by RLS, females more frequently than males. There is a variable age of onset; 33% to 40% of patients with severe RLS have symptoms before age 20. Prevalence increases with age, and symptoms progress slowly and typically worsen after age 50. Stress, fatigue and psychiatric factors can worsen symptoms.

TABLE 2 Causes of secondary RLS

RLS can be divided into 2 categories: primary and secondary. Most primary RLS cases are idiopathic; 25% to 75% of these can be familial and appear to follow an autosomal dominant inheritance. Secondary RLS can be caused by the medical conditions listed in Table 2.

The differential diagnosis also includes nocturnal leg cramps, vascular disease, and akathisia associated with neuroleptic use. Nocturnal leg cramps are sudden, unilateral, painful, involuntary muscle contractions that occur at rest. Vascular disease, such as deep venous thrombosis, must be ruled out on the basis of risk factors and physical examination. Akathisia, an excessive urge to move the entire body, differs from RLS in that it does not cause sensory disturbances in the limbs and can occur throughout the day.

MANAGEMENT Once RLS is diagnosed, there are 2 modes of therapy: nonpharmacologic and pharmacologic. Nonpharmacologic treatment may be used for those with mild symptoms. Patients should avoid alcohol, caffeine, and nicotine. Some may benefit from a whirlpool or warm bath and limb massage before bedtime.

In secondary RLS, the underlying cause must be treated. Pharmacologic treatment can be used for patients with moderate to severe symptoms. Medications can be used on an intermittent or regular basis. Continuous treatment should be considered if patients complain of symptoms at least 3 nights each week. Treatment is individualized based on the patient's age, symptoms, and comorbid illnesses.

Dopamine agonists, such as pramipexole (Mirapex) and newly approved for RLS, ropinirole (Requip), and dopaminergic agents such as carbidopa/levodopa are primarily used for most RLS patients. Augmentation of symptoms was seen in 85% of patients at doses higher than recommended. Dopamine agonists are less likely to produce augmentation or rebound. Side effects include nausea, drowsiness, and postural hypotension. Other useful drugs include benzodiazepines, opioids, anticonvulsants, and alpha₂-adrenergic agonists.

OUTCOME The patient was diagnosed with RLS based on history. She had a normal physical exam and laboratory findings. Smoking cessation was advised. She initially opted for nonpharmacologic treatment with follow-up in 1 month.