Restless Legs Syndrome

Clinical picture

• Patients describe creeping, crawling, or electric sensations deep inside the calves that they struggle to name, plus an urge they cannot resist.
• Symptoms follow a strict circadian pattern, worsening through the evening and peaking between midnight and roughly 4 a.m.
• Relief with walking or stretching is immediate but the sensations return within minutes of sitting back down.
• Sleep-onset insomnia is the usual presenting complaint, and the leg symptoms surface only on direct questioning.
• Long flights, movie theaters, dialysis chairs, and dental visits are classic settings in which the symptoms become intolerable.
• Periodic limb movements of sleep occur in roughly 80% of patients, producing partner-reported kicking and fragmented sleep.

Criteria snapshot

• An urge to move the legs, usually accompanied by uncomfortable sensations, meeting all five essential international consensus features.
• The urge begins or worsens during periods of rest or inactivity such as sitting or lying down.
• The urge is partially or totally relieved by movement, and the relief persists for as long as the movement continues.
• Symptoms are worse in the evening or night or occur only then, and DSM-5-TR requires 3 times weekly for at least 3 months with impairment.
• Mimics including leg cramps, positional discomfort, myalgia, arthritis, and habitual foot tapping must be excluded before diagnosis.

Neurobiology

• Brain iron deficiency in the substantia nigra is central even when serum indices look normal, since iron is a cofactor for dopamine synthesis.
• Ferritin is the decisive lab: target above 75 ng/mL with transferrin saturation above 20%, and supplement whenever values fall below that.
• Dopaminergic dysfunction is presynaptic with altered D2 receptor signaling, which explains both the drug response and the phenomenon of augmentation.
• MEIS1, BTBD9, and PTPRD variants confer risk, and heritability of early-onset disease approaches 50% in twin studies.
• Secondary causes include third-trimester pregnancy, end-stage renal disease, iron deficiency anemia, and peripheral neuropathy.
• Glutamatergic hyperarousal contributes, which explains why patients sleep far worse than the time lost to leg movements alone would predict.

Psychology

• The sensation is genuinely hard to verbalize, so patients are often dismissed as anxious or drug-seeking for years before diagnosis.
• Chronic delay of sleep onset produces conditioned insomnia that persists even after the leg symptoms are pharmacologically controlled.
• Depression and anxiety rates run roughly two to three times general population levels and amplify subjective symptom intensity.
• Impulse control disorders including pathological gambling, compulsive shopping, and hypersexuality emerge in 6% to 17% on dopamine agonists.
• Bedtime catastrophizing heightens sensory attention to the legs, so cognitive strategies add meaningfully to pharmacologic control.

Differential & comorbidity

• Peripheral neuropathy, akathisia, nocturnal leg cramps, and vascular claudication all mimic the syndrome but lack the circadian and movement-relief pattern.
• Antidepressants, antipsychotics, sedating antihistamines, and dopamine antagonists commonly unmask or aggravate symptoms.
• Check ferritin, transferrin saturation, renal function, and pregnancy status in every new presentation before starting any drug.
• ADHD, chronic insomnia, depression, and cardiovascular disease are consistently overrepresented comorbidities in restless legs cohorts.
• Augmentation from dopamine agonists causes earlier daily onset, spread to the arms, and greater intensity, and is treated by taper rather than dose escalation.

Pharmacologic treatment

• Iron repletion comes first: ferrous sulfate 325 mg with vitamin C on alternate days whenever ferritin is below 75 ng/mL.
• Intravenous ferric carboxymaltose is preferred for malabsorption, renal disease, intolerance, or failure of an adequate oral trial.
• Alpha-2-delta ligands are now the preferred drug class: gabapentin enacarbil 600 mg, pregabalin 150-300 mg, or gabapentin at bedtime.
• Dopamine agonists pramipexole and ropinirole have fallen out of first-line use because augmentation accumulates at roughly 7% per year.
• Low-dose opioids such as methadone 5-10 mg are reserved for refractory or augmented disease with close monitoring and a controlled substance agreement.

Psychotherapy

• CBT-I treats the conditioned insomnia layered on top of the syndrome and improves sleep beyond what medication alone achieves.
• Psychoeducation about augmentation warning signs enables early reporting instead of escalating patient requests for higher doses.
• Mindfulness-based approaches and relaxation training reduce distress and bedtime catastrophizing though not the underlying sensory urge.
• Screen at every visit for impulse control behaviors, which patients conceal and almost never spontaneously link to their medication.
• Behavioral counterstimulation strategies, from stretching routines to pneumatic compression, give patients agency at bedtime.

Adjunct options

• Eliminate evening caffeine, alcohol, and nicotine, and review every medication for dopamine-blocking, antihistaminic, or serotonergic properties.
• Regular moderate daytime exercise improves symptoms, whereas intense late-evening exercise reliably worsens them.
• Pneumatic compression devices, counterstrain stretching, and near-infrared light have modest supportive evidence in mild disease.
• Recheck ferritin every 3 to 6 months during repletion and separate oral iron from tea, calcium, and proton pump inhibitors.
• Track severity with the IRLS Rating Scale, where a drop of 6 or more points marks a clinically meaningful treatment response.

Clinical pearls

• Check ferritin in every case; under 75 ng/mL, give iron before any other drug.
• Dopamine agonists cause augmentation; alpha-2-delta ligands are now preferred.
• Worsening on a dopamine agonist means taper, not a dose increase.