An urge to move with L-thyroxine: clinical, biochemical, and polysomnographic correlation.
We report on the cause and effect relationship of restless legs syndrome (RLS) with L-thyroxine treatment in a hypothyroid patient with low serum ferritin. Upon challenge and withdrawal of L-thyroxine, there was a significant change in the International Restless Legs Syndrome Study Group severity score (26/40 to 6/40), the periodic limb movements (PMLS) index (20/hour to 10/hour), the number of arousals due to PLMS (59 to 22), sleep efficiency (74 to 85%), and biochemical parameters. RLS symptoms can complicate thyroxine replacement in at-risk hypothyroid patients with low serum ferritin. Early diagnosis and iron replacement could significantly reduce patient morbidity.
Tan
Eng-King
EK
Department of Neurology, Singapore General Hospital, Singapore. gnrtek@sgh.com.sg
Ho
Su-Chin
SC
Koh
Leonard
L
Pavanni
Ratnagopal
R
D005293:Ferritins / Q000097:blood; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D007501:Iron / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D017286:Polysomnography; D012148:Restless Legs Syndrome / Q000139:chemically induced* / Q000175:diagnosis; D012307:Risk Factors; D013960:Thyroid Function Tests; D013967:Thyroiditis, Autoimmune / Q000188:drug therapy*; D013974:Thyroxine / Q000009:adverse effects* / Q000627:therapeutic use
D005293:Ferritins; D007501:Iron; D013974:Thyroxine