HMS 3/06; Nejm 2003;348:2103; Practical Neurol 2003;3:204; ACP J Club 2000;132:24; NIH Mar 2000 publ #00-3788

Cause:

Primary, autosomal dominant on chromosome 12q

Secondary causes: iron deficiency, diabetes, drug-induced (TCAs, lithium, SSRIs), uremia, cord and peripheral nerve diseases, transiently in pregnancy (20%)

Pathophys:Dopamine deficiency; iron is a cofactor for tyrosine hydroxylase needed for tyr dopamine

Common; 2-5+% prevalence; incr w age, but 35% of adults w severe disease have onset in childhood; strong familial association, esp if onset <40 yrs. Incr incid in pts on hemodialysis and those w iron deficiency. F > M. 80% of pts w restless leg syndrome have PLMS, but only 30% of pts w PLMS have RLS (Jags 2005;53:suppl 264)

Sx: Creepy crawly leg (usually) paresthesias/akathisias relieved by movement. Positive fam hx. Sleep interference

Si:Normal neurologic exam; may have involuntary periodic jerking limb movements, esp when asleep (nocturnal myoclonus) as well as semirhythmnic leg movements during sleep (periodic limb movements) but taht are nonspecific

R/o nocturnal muscle cramps

Lab: Chem: R/o secondary causes w iron and TIBC, ferritin, BUN/creat, FBS

Rx:

(Nejm 2003;348:2106)

1st:

• D/c SSRIs, tricyclics, L-DOPA, which helps initially but then augments sx
• FeSO₄ esp if ferritin <50; plus
• Dopamine agonists (2-h onset) like pergolide 0.10-0.75 mg po hs (Neurol 1999;52:944), bromocryptine, pramipexole (Mirapex) (Med Let 2007;49:26), ropinirole (Requip) in lowest possible dose

Other:

• Anticonvulsants: valproate, gabapentin (Neurontin, Horizant: ER form)
• Opiates: propoxyphene, Tylenol 3 (15-30 mg hs), oxycodone, methadone
• Clonidine, baclofen, or clonazepam (Klonopin), carbamazepine, gabapentin (maybe—ACP J Club 2003;139:17)
• Cognitive behavioral therapy × 6+ sessions