Restless Legs Syndrome (RLS): Symptoms & Treatment

Restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a neurological sensorimotor disorder characterized by an irresistible urge to move the legs, typically accompanied by uncomfortable sensations. Symptoms occur primarily at rest, worsen in the evening and nighttime, and are temporarily relieved by movement.

RLS affects up to 10% of the adult population, with approximately 2-3% experiencing symptoms severe enough to require medical treatment. It is twice as common in women as men, and prevalence increases with age. The condition can significantly impair sleep onset, leading to chronic sleep deprivation, daytime fatigue, and reduced quality of life.

RLS is classified as both a neurological disorder and a sleep disorder because its primary impact on patients is disruption of the ability to fall asleep and maintain sleep. The International Restless Legs Syndrome Study Group (IRLSSG) has established standardized diagnostic criteria to distinguish RLS from other conditions that may mimic its symptoms.

Diagnosis requires meeting all five essential criteria established by the IRLSSG:

• Urge to move the legs, usually accompanied by uncomfortable sensations described as crawling, tingling, pulling, throbbing, itching, or electric-like feelings deep within the legs
• Symptoms begin or worsen during rest or inactivity — sitting, lying down, or any prolonged immobility
• Symptoms are partially or totally relieved by movement — walking, stretching, or jiggling the legs
• Symptoms are worse in the evening or at night compared to daytime (circadian pattern)
• Symptoms are not solely accounted for by another condition (leg cramps, positional discomfort, venous stasis)

Associated Features

• Periodic limb movements of sleep (PLMS): Repetitive leg jerks during sleep occur in 80-90% of RLS patients and may be documented on polysomnography
• Sleep-onset difficulty: The primary sleep complaint — unable to fall asleep due to leg discomfort
• Family history: Present in 40-60% of cases, suggesting significant genetic contribution
• Response to dopaminergic therapy: Improvement with dopamine agonists supports the diagnosis

The pathophysiology of RLS involves dysfunction in brain iron metabolism and the dopaminergic system:

Iron Deficiency

Brain iron deficiency is central to RLS pathology. Iron is required for dopamine synthesis (as a cofactor for tyrosine hydroxylase) and is consistently found to be low in the substantia nigra of RLS patients, even when peripheral blood iron levels are normal. A serum ferritin level below 75 ng/mL is considered insufficient in the context of RLS and warrants supplementation.

Dopamine Dysfunction

The circadian pattern of RLS (worsening at night) correlates with the natural nighttime decrease in brain dopamine activity. Dopaminergic medications provide symptomatic relief, confirming involvement of this system. However, long-term dopamine agonist use can lead to augmentation (paradoxical worsening).

Secondary Causes

• Iron deficiency anemia — most common reversible cause
• Pregnancy — affects 25-30% of pregnant women, usually resolving after delivery
• End-stage renal disease — affects 20-60% of dialysis patients
• Peripheral neuropathy
• Medications — antidepressants (SSRIs, SNRIs), antihistamines, dopamine-blocking agents

Iron Supplementation

First-line treatment when serum ferritin is below 75 ng/mL. Oral iron (325mg ferrous sulfate with vitamin C on an empty stomach, every other day) or intravenous iron (when oral is ineffective or not tolerated). Target ferritin: above 100 ng/mL.

Alpha-2-Delta Ligands (First-Line Pharmacotherapy)

Gabapentin enacarbil (Horizant), pregabalin, or gabapentin. Now recommended as initial pharmacotherapy over dopamine agonists due to lower risk of augmentation. Particularly effective for RLS with pain or comorbid insomnia.

Dopamine Agonists

Pramipexole, ropinirole, rotigotine patch. Previously first-line but now reserved for cases unresponsive to alpha-2-delta ligands due to augmentation risk (up to 50% of patients on long-term therapy). Use the lowest effective dose for the shortest duration.

Opioids

Low-dose opioids (oxycodone, tramadol) are effective for refractory RLS or augmentation management. Reserved for severe cases unresponsive to other treatments due to abuse potential and regulatory considerations.

Addressing Secondary Causes

• Correcting iron deficiency
• Discontinuing exacerbating medications (SSRIs, antihistamines)
• Managing underlying conditions (renal disease, neuropathy)

Non-pharmacological strategies that can reduce RLS symptom burden:

• Regular moderate exercise — walking, cycling, yoga. Avoid vigorous exercise close to bedtime which may temporarily worsen symptoms.
• Leg massage or stretching before bed
• Warm baths in the evening to relax leg muscles
• Pneumatic compression devices — some patients find relief with sequential compression
• Distraction techniques — mental engagement (puzzles, conversation) during rest can reduce awareness of symptoms
• Avoid triggers: Caffeine, alcohol, nicotine (all worsen RLS)
• Sleep hygiene: Consistent bedtime, cool dark room, avoiding prolonged sitting in the evening
• Iron-rich diet: Red meat, spinach, lentils, fortified cereals (though dietary iron alone rarely corrects RLS-related deficiency)

Many patients find that combining lifestyle measures with appropriate medical treatment provides the best symptom control. Regular follow-up with your physician is important to monitor for augmentation if using dopaminergic therapy.