- Clinical science
Restless legs syndrome (RLS), also referred to as Willis-Ekbom disease (WED), is a relatively common, neurological sleep disorder characterized by unpleasant sensations in the legs and a strong urge to move them. The urge increases during periods of rest, especially in the evenings, and may diminish with movement. Primary RLS is idiopathic and is often associated with a positive family history. Secondary RLS is less common and can result from a variety of underlying conditions, including iron deficiency, attention deficit hyperactivity disorder (ADHD), uremia, and Parkinson's disease. Diagnostic tests are used to exclude secondary causes of RLS (these tests include ferritin levels, vitamin levels, autoantibody assays, thyroid profile, etc.) Treatment for primary RLS includes levodopa and dopamine agonists, while secondary RLS is managed by treating the underlying causes. If left untreated, RLS can cause significant social and functional impairment.
- RLS affects approx. 5–15% of the general US population
- Sex: ♀ > ♂
- Peak incidence
- Primary: < 45 years of age (often misdiagnosed as growing pains in childhood)
- Secondary: Although onset of symptoms occurs at < 20 years of age, most cases are diagnosed after 45 years
Epidemiological data refers to the US, unless otherwise specified.
- Primary (common): idiopathic, but is familial in 25–75% of cases
- Chronic conditions
- Iron deficiency with or without anemia, vitamin deficiency
- Peripheral neuropathy (i.e., in diabetes mellitus)
- End-stage renal disease (uremia)
- Inflammatory conditions: celiac disease, rheumatoid arthritis, inflammatory bowel diseases
- Psychiatric: depression, anxiety disorders
- Neurological: Parkinson's disease, polyneuropathies, spinal cord diseases, multiple sclerosis
- Drugs: antidepressants (e.g., TCAs, SSRIs, SNRIs), dopamine antagonists (neuroleptics, metoclopramide, MDMA), lithium, beta blockers
- Chronic conditions
- A recurrent urge to move the legs that is typically relieved by movement and worsened by rest.
- Often worse in the evening and at night. May occur exclusively at night.
- Often accompanied by dysesthesias (e.g., pain, pins and needles, itching, tickling, or crawling sensations).
- ∼ 85% of patients exhibit associated periodic leg movements of sleep (PLMS): This is characterized by involuntary and forceful dorsiflexions of the foot during sleep.
- Can often lead to social, mental, and/or functional distress and impairment
- Occurs in the absence of any other explicable cause of symptoms
- Clinical features of underlying disease in secondary RLS are seen
Additional testing may be indicated to rule out an underlying disease, including conducting laboratory tests, nerve conduction studies, polysomnogram, and needle electromyogram.
- Laboratory tests
- : quantification of periodic limb movements of sleep (PLMS)
- Needle electromyogram and nerve conduction studies: if a polyneuropathy or radiculopathy is suspected
Treatment for primary RLS is largely symptomatic. Depending on the underlying cause, secondary RLS can be completely cured. Intermittent treatment may be necessary for recurrent cases with spontaneous remission.
- Medical therapy: indicated in patients with significant functional and sleep impairment