Restless Legs Syndrome

Introduction

• Movement disorder affecting 10% of population
• Prevalence increases with age
• More common in females
• Genetic predisposition (especially for earlier onset)

Causes

• Primary (idiopathic)
• Secondary
  • Iron deficiency anaemia
  • End stage renal disease requiring haemodialysis
  • Pregnancy
  • Medications
    • Neuroleptics, anti-emetics, lithium, anti-depressants, anti-histamines

Symptoms

• Strong, irresistible urge to move one or both legs
  • With increasing severity, it may spread to other parts of body
• Increasing compulsion which becomes unpleasant, even unbearable if not performed
  • May be suppressible for short period which may lead to involuntary jerking
• Sufferers may start to avoid embarrassing social situations e.g. meetings, theatres

Diagnosis

• For RLS to be diagnosed, an urge to move the legs must be accompanied by:
  • A worsening of symptoms with rest
  • Improvement by movement of legs o Worsening in the evening or at night
• Supportive features
  • Family history – 1st degree relative
  • Initial positive response to levodopa
  • Increased periodic leg movements during sleep or on waking
• Associated features
  • Age of onset is usually in middle age or older and is progressive in nature
  • Sleep disorder
  • Neurological examination usually normal

What else could it be?

• Nocturnal leg cramps
• Painful peripheral neuropathy
• Arthritis
• Vascular claudication

Treatment

• Treat secondary causes
  • If iron deficient (ferritin is less than 50ng/mL), treat with iron replacement
  • Renal transplantation may improve symptoms
  • Pregnancy: Reassurance that RLS will improve with delivery
  • Rationalise medications that may trigger RLS
• Primary RLS
  • Non-pharmacological
    • Lifestyle modifications
      • Limit caffeine, tobacco, alcohol
      • Mental stimulation exercises
      • Weight loss – resistance training and aerobic exercise
  • Pharmacological
    • Dopamine agonists
    • Carbidopa / levodopa
    • Gabapentin
    • Opioids
    • Benzodiazepines

Prognosis

• Progressive condition
  • There may be some spontaneous improvement in some people
  • But there is a tendency for symptoms to recur
• Secondary RLS may be successfully treated if underlying causes are addressed
• Medications may provide some relief

References
Bayard M Avonda T Wadzinski J. Restless Legs Syndrome. American Family Physician. Volume 78, No 2, July 15, 2008 pp 235-240
Benes H Walters AS Allen RP Hening WA Kohnen R. Definition of Restless Legs Syndrome, How to Diagnose It, and How to Differentiate It from RLS Mimics. Volume 22 Suppl 18 2007 pp S401-S408