Ekbom's syndrome; Nocturnal leg cramps; Periodic limb movement disorder
Restless legs syndrome (RLS) is an unsettling and poorly understood movement disorder affecting 3 - 15% of the general population. RLS can affect both children and adults. Although effective treatments are available, the condition often remains undiagnosed.
Symptoms of RLS. The core symptom of RLS is an irresistible urge to move the legs (medically known as akathisia). Some people describe this symptom as a sense of unease and weariness in the lower leg, which is aggravated by rest and relieved by movement. Specific characteristics of RLS include:
Late-onset and Early-onset Forms. There appear to be two forms of RLS, early-onset and late-onset. Each form may have different characteristics:
The medical term for periodic limb movement disorder (PLMD) is nocturnal myoclonus. PLMD symptoms include:
Although 80% of RLS sufferers have PLMD, only about 30% of people with PLMD also have RLS. While treatments for the two conditions are similar, PLMD is a separate syndrome. PLMD is also very common in narcolepsy, a sleep disorder that causes people to fall asleep suddenly and uncontrollably.
Cramps that awaken people during sleep are very common, and they are not part of restless legs syndrome or periodic limb movement disorder. They can be very painful and may cause a person jump out of bed in the middle of the night. They typically affect a specific area of the calf or the sole of the foot.
Benign nocturnal leg cramps, sometimes known as a charley horse, are muscle spasms in the calf that can occur one or many times during the night. Cramping may also occur in the soles of the feet. They typically last from a few seconds to a few minutes. Some people experience them regularly, others only on isolated occurrences.
Causes of Nocturnal Leg Cramps. In most cases, the cause of nocturnal leg cramps remains unknown. Among the conditions that might cause leg cramps are:
Individuals at Higher Risk for Nocturnal Leg Cramps. Nocturnal leg cramps occur at all ages but peak at different times. They are particularly common in adolescence, during pregnancy, and in older age, affecting up to 70% of adults over age 50 at some point.
Pregnant women and those taking diuretics are also at risk for leg cramps because of low calcium levels and an imbalance in calcium and phosphorus.
Consequences of Nocturnal Leg Cramps. Nocturnal leg cramps, like restless legs syndrome, rarely have any serious consequences. However, they can be extremely painful and long lasting. In some cases, severe and persistent symptoms can cause chronic insomnia and considerable mental distress.
Bayard M, Avonda T, Wadzinski, J. Restless Legs Syndrome.American Family Physician. 2008;78(2): 235-240.
Bogan RK, Fry JM, Schmidt MH, Carson SW, Ritchie SY. Ropinirole in the treatment of patients with restless legs syndrome: a US-based randomized, double-blind, placebo-controlled clinical trial. Mayo Clin Proc. 2006 Jan;81(1):17-27.
Claman DM; Redline S; Blackwell T, Ancoli-Israel S, Surovec S, Scott N, et al. Prevalence and correlates of periodic limb movements in older women. J Clin Sleep Med. 2006 Oct;2(4):438-445.
Gamaldo CE, Earley CJ. Restless Legs Syndrome. Chest. 2006;130(5):1596-1604.
Lohmann-Hedrich K, Neumann A, Kleensang A, et al. Evidence for linkage of restless legs syndrome to chromosome 9p: are there two distinct loci? Neurology. 2008;70(9):686-694.
Merlino G, Fratticci L, Valente M, et al. Association of restless legs syndrome in type 2 diabetes: a case-control study. Sleep. 2007; 30(7): 866-71.
Oertel WH, Benes H, Bodenschatz R, Peglau I, Warmuth R, Happe S, et al. Efficacy of cabergoline in restless legs syndrome: a placebo-controlled study with polysomnography (CATOR). Neurology. 2006 Sep 26;67(6):1040-6.
Ong KH, Tan HL, Tam LP, et al. Accuracy of serum transferrin receptor levels in the diagnosis of iron deficiency among hospital patients in a population with a high prevalence of thalassaemia trait. Int J Lab Hematol. 2008;30(6):487-493
Partinen M, Hirvonen K, Jama L, Alakuijala A, Hublin C, Tamminen I, et al. Efficacy and safety of pramipexole in idiopathic restless legs syndrome: a polysomnographic dose-finding study--the PRELUDE study. Sleep Med. 2006 Aug;7(5):407-17.
Picchietti D, Winkelman JW. Restless legs syndrome, periodic limb movements in sleep, and depression. Sleep. 2005 Jul 1;28(7):891-8.
Picchietti D. Restless legs syndrome: prevalence and impact in children and adolescents--the Peds REST study. Pediatrics. 2007; 120(2): 253-66.
Stefansson H, Rye DB, Hicks A, et al. A Genetic Risk Factor for Periodic Limb Movements in Sleep. N Engl J Med. 2007;357:639-47.
Winkelman JW, Sethi KD, Kushida CA, Becker PM, Koester J, Cappola JJ, et al. Efficacy and safety of pramipexole in restless legs syndrome. Neurology. 2006 Sep 26;67(6):1034-9.
Winkelmann J, Schormair B, Lichtner P, et al. Genome-wide association study of restless legs syndrome identifies common variants in three genomic regions. Nat Genet (in press). [cited in: Winkelmann J. Periodic Limb Movements in Sleep - Endophenotype for Restless Legs Syndrome? N Engl J Med. 2007; 357:703-05.
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