Peripheral hypoxia in restless legs syndrome (Willis-Ekbom disease)

• Published in: Neurology Vol. 82; no. 21; pp. 1856 - 1861
• Main Authors: Salminen, Aaro V, Rimpilä, Ville, Polo, Olli
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Academy of Neurology 27-05-2014; Lippincott Williams & Wilkins
• Subjects: Biological and medical sciences; Case-Control Studies; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Humans; Hypoxia - physiopathology; Leg - physiopathology; Male; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Restless Legs Syndrome - physiopathology; Sensitivity disorder; Restless legs syndrome; Hypoxia; Oxygen; Nervous system diseases; Neurological disorder
• ISSN: 0028-3878; 1526-632X
• DOI: 10.1212/WNL.0000000000000454

OBJECTIVE:A case-control study to measure oxygen and carbon dioxide partial pressures in the legs in order to assess the involvement of peripheral hypoxia or hypercapnia in the pathogenesis of restless legs syndrome (RLS).
METHODS:RLS severity was assessed with a standard questionnaire. Suggested immobilization tests were performed twice in 15 patients with RLS and 14 healthy controls. Patients with RLS participated in the tests with and without pramipexole medication. During the tests, peripheral oxygen and carbon dioxide partial pressures were measured noninvasively on the skin of the legs and the chest.
RESULTS:During immobilization, the patients with RLS had lower partial pressure of oxygen in their legs (5.54 vs 7.19 kPa, p < 0.01) but not on the chest (8.75 vs 8.20 kPa, p = 0.355). More severe RLS correlated with high chest-to-foot oxygen gradient (ρ = 0.692, p < 0.01). Carbon dioxide levels did not differ between the groups. Pramipexole corrected the peripheral hypoxia toward the levels observed in the controls (from 5.54 to 6.65 kPa, p < 0.05).
CONCLUSIONS:Peripheral hypoxia is associated with the appearance of RLS symptoms. Strong correlation with RLS severity suggests a close pathophysiologic link between peripheral hypoxia and the symptoms of RLS. This is further supported by the simultaneous reversal of hypoxia and discomfort by dopaminergic treatment.