Pathophysiology
- Poorly understood
- Reduced basal ganglia iron is the most consistent neural correlate
- Symptoms can improve with dopaminergic medications
Epidemiology
- Family history in 50%, high twin concordance
- Other risk factors include iron deficiency, uraemia and chronic kidney disease, pregnancy and peripheral neuropathy
Symptoms
- Unpleasant urge to move the legs
- Description often subjective and variable
- Worse during inactivity in the evenings
- Made worse with diphenhydramine (often taken to help with sleep)
- Relieved by movement
- Characteristic limb movements during sleep, which can be associated with waking.
On examination
Diagnosis
Differential:
- Hypnic myoclonic jerks
- Akathisia (associated with neuroleptics)
- Cramps
- Vascular insufficiency
Tests:
- FBC & Fe studies – to assess iron
- U&E – to assess uraemia
Diagnosis is clinical.
Treatments
- Spontaneous remission in at least 30%
- Iron replacement not supported by meta-analyses of randomised trials
- Good sleep hygiene
- Dopamine agonists show best response in chronic sufferers
- Pramipexole and Ropinirole have both shown superiority over placebo
- Pregabalin has also been shown to be superior to placebo