Restless Legs Syndrome (RLS) — Causes, Symptoms & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Restless legs syndrome (RLS) — also known as Willis-Ekbom disease (WED) — is a common, chronic, sensorimotor neurological disorder characterised by an irresistible urge to move the legs (and sometimes arms), usually accompanied by uncomfortable, unpleasant sensations in the limbs. It affects 5–10% of adults in European and North American populations, with approximately 2–3% experiencing clinically significant, quality-of-life-impairing symptoms. RLS is significantly more common in women (2:1 female predominance) and prevalence increases with age. It is diagnosed entirely on clinical criteria — the four essential IRLSSG (International Restless Legs Syndrome Study Group) criteria: an urge to move the legs (or arms), uncomfortable sensations in the legs, worsening at rest (sitting or lying), and relieved by movement (walking, stretching). The circadian component — symptoms exclusively or predominantly worse in the evening and night — is a fifth supportive criterion. RLS causes significant sleep disturbance, insomnia, daytime fatigue, and quality-of-life impairment comparable to chronic pain conditions. It is frequently underdiagnosed or misattributed to growing pains, peripheral neuropathy, or anxiety.

RLS is classified as primary (idiopathic — no identifiable underlying cause, strong genetic component) or secondary (symptomatic — caused by or associated with an underlying condition). Primary RLS: strongly familial — 40–92% heritability; genome-wide association studies (GWAS) have identified variants in BTBD9, MEIS1, MAP2K5, PTPRD, and TOX3 genes. First-degree relatives have 3–6 times increased risk. Iron deficiency and dopamine system dysfunction are central to the pathophysiology: iron is required for tyrosine hydroxylase (dopamine synthesis) activity; brain iron deficiency (even with normal serum iron — reflected in low CSF ferritin) impairs dopaminergic neurotransmission. Secondary RLS causes: iron deficiency anaemia (serum ferritin <75 mcg/L — the most important treatable cause; restoring iron stores resolves RLS in a significant proportion), pregnancy (affects 25–30% of pregnant women in the third trimester — iron and folate deficiency), chronic kidney disease (end-stage renal failure — 25% prevalence in dialysis patients), peripheral neuropathy (diabetes, alcohol-related), Parkinson's disease (dopamine deficiency overlap), multiple sclerosis. Medications that can cause or worsen RLS: dopamine antagonists (metoclopramide, prochlorperazine, haloperidol, risperidone — block dopamine receptors), antidepressants (SSRIs, mirtazapine, TCA), antihistamines (diphenhydramine, promethazine — dopamine antagonist properties), lithium. Risk factors: female sex, positive family history, increasing age, iron deficiency (including blood donation, menstruation), pregnancy, CKD, peripheral neuropathy.

The four cardinal features of RLS are necessary for diagnosis: an urge to move the legs — usually accompanied by uncomfortable sensations described variably as creeping, crawling, pulling, tugging, gnawing, aching, or tingling deep within the legs (rarely just an urge with no sensory component); the urge to move starts or worsens at rest or inactivity (sitting in a car, cinema, aircraft, lying in bed); the urge to move is partially or completely relieved by movement (walking, stretching, kicking — temporary relief only, returning when still); symptoms are exclusively or predominantly worse in the evening or night (circadian pattern — related to lowest dopamine activity in the evening). The sensations are located deep within the limbs, not on the skin surface (distinguishing from neuropathy-related tingling or burning). Bilateral symptoms are most common (67%); approximately 50% also have arm involvement. Periodic limb movements of sleep (PLMS): associated movement disorder — repetitive, stereotyped leg (or arm) movements during sleep (30% of adults >65 have PLMS, but it is only clinically significant when causing arousal and sleep disruption — periodic limb movement disorder — PLMD). PLMS disturbs sleep continuity and wakes the bed partner. Consequences: sleep-onset insomnia (inability to fall asleep due to evening symptoms), sleep maintenance insomnia (awakenings from leg discomfort and movement), excessive daytime sleepiness, fatigue, mood disturbance, and reduced quality of life. Augmentation: paradoxical worsening of RLS after long-term dopamine agonist therapy — symptoms begin earlier in the day, more intense, spread to arms — an important treatment complication requiring management.

RLS is a clinical diagnosis based on the four IRLSSG criteria — no diagnostic test is required for primary RLS. Essential criteria (all four must be present): (1) an urge to move the legs; (2) starts or worsens at rest; (3) partially or completely relieved by movement; (4) occurs predominantly in the evening or night. Diagnosis is supported by: positive family history, response to dopaminergic therapy, and presence of PLMS on polysomnography. Additional supportive investigations: serum ferritin (target >75 mcg/L — the most important blood test in RLS; treating iron deficiency can resolve symptoms completely); serum iron, transferrin saturation, full blood count (anaemia assessment); serum B12 and folate; renal function (CKD-related secondary RLS); HbA1c (diabetes-related peripheral neuropathy). Polysomnography (PSG — overnight sleep study): not required for diagnosis but recommended when PLMD is suspected as the primary cause of sleep disruption, or to distinguish RLS from other sleep disorders. Neurophysiology (nerve conduction studies/EMG): if peripheral neuropathy is suspected. IRLSS (International RLS Severity Scale): validated 10-question questionnaire scoring RLS severity — mild (1–10), moderate (11–20), severe (21–30), very severe (31–40) — used to guide treatment and monitor response. Mimics to exclude: peripheral neuropathy (burning or numbness — does not worsen at rest), anxiety with leg restlessness (no sensory component, not worse at rest or at night), akathisia (inner restlessness from medication — no sensory leg component), peripheral vascular disease (intermittent claudication — pain with exercise, not at rest), positional discomfort.

Non-pharmacological: trigger identification and avoidance — caffeine (especially evening), alcohol, and nicotine worsen RLS; identify and stop aggravating medications (SSRIs, mirtazapine, antihistamines, dopamine antagonists); good sleep hygiene; leg massage, stretching, and physical activity (moderate — vigorous exercise can paradoxically worsen symptoms). Iron supplementation: for serum ferritin <75 mcg/L (even if haemoglobin is normal) — oral ferrous sulfate 325 mg OD–TDS with vitamin C on an empty stomach; aim ferritin >75–100 mcg/L (some guidelines suggest >300 mcg/L); may take 3–6 months; IV iron sucrose or ferric carboxymaltose for those who cannot tolerate or absorb oral iron or with rapid IV correction needed. Dopamine agonists (first-line pharmacological therapy for moderate-severe RLS): pramipexole 0.088–0.54 mg OD 2–3 hours before symptoms; ropinirole 0.25–4 mg OD; rotigotine transdermal patch 1–3 mg/24h (particularly useful for early morning symptoms). Effective in 70–80% of patients. Augmentation is a significant concern with long-term use — earlier symptom onset, greater intensity, spread to arms — more common with higher doses and longer treatment duration. Minimise dopamine agonist doses to reduce augmentation risk. Alpha-2-delta calcium channel ligands (preferred when augmentation is a concern or for patients with concurrent anxiety, pain, or insomnia): pregabalin 75–300 mg OD at night (most evidence — PHASE 3 trial showing non-inferiority to pramipexole with lower augmentation rate); gabapentin 300–2,400 mg OD at night. Opioids (buprenorphine, oxycodone — extended-release oxycodone + naloxone): for severe, refractory RLS or augmentation on dopamine agonists — very effective but limited by addiction potential. Clonazepam (benzodiazepine): for PLMS-related sleep disruption — improves sleep quality but does not reduce leg movements. Switching from dopamine agonist to alpha-2-delta ligand recommended when augmentation occurs — requires gradual wean of dopamine agonist while starting pregabalin.

Chronic, severe RLS causes significant sleep deprivation — resulting in excessive daytime sleepiness, impaired cognitive function (concentration, memory, executive function), mood disturbance (depression and anxiety), and substantially reduced quality of life comparable in burden to chronic pain conditions. Some population studies suggest that RLS with concurrent periodic limb movements (PLMS) is independently associated with elevated cardiovascular disease risk — possibly through nocturnal arousals causing blood pressure surges; this association remains under study. Augmentation is the most important iatrogenic complication — paradoxical worsening of symptoms (earlier symptom onset, increased intensity, spread to arms and trunk) from long-term dopamine agonist therapy affects up to 50% of patients on long-term pramipexole or ropinirole; management requires gradual weaning and switching to alpha-2-delta ligands (pregabalin) or opioids. Work performance impairment, increased absenteeism, and disability rates are documented in severe RLS. Pregnancy-related RLS causes sleep deprivation with potential adverse obstetric outcomes. Depression is comorbid in approximately 20–30% of chronic RLS patients.

Many RLS cases cannot be prevented due to strong genetic predisposition, but secondary RLS and exacerbations are preventable. Maintain adequate iron stores: all women of reproductive age, blood donors, vegetarians, and vegans should monitor ferritin annually and supplement to maintain ferritin above 75 mcg/L. Avoid RLS-aggravating substances: eliminate or reduce caffeine (coffee, tea, cola, energy drinks — particularly in the afternoon and evening), avoid alcohol within 4 hours of bedtime, stop smoking (nicotine worsens dopaminergic dysfunction). Regular moderate exercise (30 minutes daily walking) improves RLS symptoms. Check medications for dopamine-antagonist or serotonergic antidepressant effects — discuss alternatives with your doctor if these are necessary and worsen RLS. In pregnancy: check ferritin and supplement iron; folate supplementation standard; moderate physical activity; RLS usually resolves within 4 weeks of delivery. Treat underlying conditions: diabetes control (prevents peripheral neuropathy — secondary RLS contributor), CKD management (dialysis scheduling, renal transplant resolves RLS in most cases). Leg massage, warm baths, and mental engagement (puzzles, video games) provide temporary relief and can help manage intermittent symptoms.

See your GP if you experience the characteristic RLS symptoms — uncomfortable sensations in your legs at rest (particularly in the evenings) with an urge to move that partially relieves the discomfort — especially if this is disrupting your sleep or daytime functioning. RLS is a recognisable clinical syndrome that GPs diagnose and treat, but is frequently misdiagnosed as anxiety, growing pains, or circulation problems. Seek specialist (neurologist or sleep medicine) referral for: severe, refractory RLS not responding to iron supplementation or first-line dopamine agonists; suspected augmentation (symptoms worsening and starting earlier during the day after dopamine agonist treatment); complex secondary RLS (CKD, neuropathy, Parkinson's disease); or if you are pregnant and experiencing severe RLS (treatment options are limited in pregnancy — iron is first-line; low-dose clonazepam or opioids only if essential and after first trimester).