{{Short description|Pathological, often painful, involuntary muscle contraction}} {{Other uses|Cramp (disambiguation)}} {{Distinguish|Seizure|Spasm}} {{Infobox medical condition | name = Cramp | synonyms = Muscle cramp, charley horse | image = | caption = | pronounce = | field = | symptoms = Sudden muscle pain and a paralysis-like immobility | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = Stretching, massage, and drinking liquids | medication = | prognosis = | frequency = | deaths = }}
A '''cramp''' is a sudden, involuntary, painful contraction of one or more skeletal muscles,<ref name=":2">{{Cite journal |last1=Minetto |first1=Marco Alessandro |last2=Holobar |first2=Aleš |last3=Botter |first3=Alberto |last4=Farina |first4=Dario |date=Jan 2013 |title=Origin and development of muscle cramps |journal=Exercise and Sport Sciences Reviews |volume=41 |issue=1 |pages=3–10 |doi=10.1097/JES.0b013e3182724817 |issn=1538-3008 |pmid=23038243|s2cid=15263712 |doi-access=free }}</ref><ref name=":3">{{Cite journal |last1=Marotta |first1=P. J. |last2=Graziadei |first2=I. W. |last3=Ghent |first3=C. N. |date=Nov 2000 |title=Muscle cramps: a 'complication' of cirrhosis |journal=Canadian Journal of Gastroenterology |volume=14 Suppl D |pages=21D–25D |doi=10.1155/2000/214916 |issn=0835-7900 |pmid=11110608 |doi-access=free}}</ref> or an overshortening of such associated with electrical activity.<ref>{{Cite book |last1=Benzon |first1=Honorio |url=https://books.google.com/books?id=9UuAWD2FTFsC&pg=PA141 |title=Essentials of Pain Medicine E-book |last2=Raja |first2=Srinivasa N. |last3=Fishman |first3=Scott E. |last4=Liu |first4=Spencer S. |last5=Cohen |first5=Steven P. |date=2011-06-30 |publisher=Elsevier Health Sciences |isbn=978-1-4377-3593-2 |language=en}}</ref> While generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the affected muscle. A cramp usually goes away on its own over several seconds or (sometimes) minutes.<ref>{{Cite web |title=Muscle Cramps |url=https://medlineplus.gov/musclecramps.html |access-date=2022-09-15 |website=medlineplus.gov}}</ref> Cramps are common and tend to occur at rest, usually at night (nocturnal leg cramps).<ref name=":3" /><ref>{{Cite web |title=Nocturnal leg cramps |url=https://www.uptodate.com/contents/nocturnal-leg-cramps |access-date=2022-09-21 |website=UpToDate}}</ref> They are also often associated with pregnancy, physical exercise or overexertion, and age (common in older adults); in such cases, cramps are called idiopathic because there is no underlying pathology. In addition to those benign conditions, cramps are also associated with many pathological conditions.<ref name=":3" /><ref name=":1">{{Cite journal|last1=Garrison|first1=Scott R.|last2=Korownyk|first2=Christina S.|last3=Kolber|first3=Michael R.|last4=Allan|first4=G. Michael|last5=Musini|first5=Vijaya M.|last6=Sekhon|first6=Ravneet K.|last7=Dugré|first7=Nicolas|date=September 2020|title=Magnesium for skeletal muscle cramps|journal=The Cochrane Database of Systematic Reviews|volume=2020|issue=9|article-number=CD009402|doi=10.1002/14651858.CD009402.pub3|issn=1469-493X|pmid=32956536|pmc=8094171}}</ref>
The definition of a cramp is narrower than that of a muscle spasm: spasms include any involuntary abnormal muscle contractions, while cramps are sustained and painful.<ref name=":2" /><ref>{{Cite web |title=Muscle Cramps (Charley Horse) and Muscle Spasm Remedies |url=https://www.emedicinehealth.com/slideshow_pictures_muscle_cramps_and_muscle_spasms/article_em.htm |access-date=2022-09-25 |website=eMedicineHealth |language=en}}</ref> True cramps can be distinguished from other cramp-like conditions. Cramps are different from muscle contracture, which is also painful and involuntary, but which is electrically silent. The main distinguishing features of cramps from dystonia are suddenness with acute onset of pain, involvement of only one muscle, and spontaneous resolution of cramps or their resolution after stretching the affected muscle.<ref name=":3" /> Restless leg syndrome is not considered the same as muscle cramps and should not be confused with rest cramps.<ref name=":1" /> Cramps are sometimes also called a "Charley horse", which is a lay term used by people in the United States.
Under normal circumstances, skeletal muscles can be voluntarily controlled,<ref>{{Cite web |title=Quick Facts:Muscles |url=https://www.msdmanuals.com/home/quick-facts-bone-joint-and-muscle-disorders/biology-of-muscles-and-bones/muscles |access-date=2025-10-21 |website=MSD Manual Consumer Version |language=en}}</ref> and any of them can be affected by cramps.<ref name=":4">{{Citation |last1=Bordoni |first1=Bruno |title=Muscle Cramps |date=2025 |work=StatPearls |url=http://www.ncbi.nlm.nih.gov/books/NBK499895/ |access-date=2025-10-21 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29763070 |last2=Goldin |first2=Jennifer |last3=Sugumar |first3=Kavin}}</ref> Skeletal muscles that are most often affected by cramps are the calves, thighs, and arches of the foot.<ref>{{Cite book |last=Colberg |first=Sheri R. |url=https://books.google.com/books?id=hJSHDwAAQBAJ&pg=PA177 |title=The Athlete's Guide to Diabetes |date=2019-02-08 |publisher=Human Kinetics |isbn=978-1-4925-8873-3 |page=177 |language=en}}</ref><ref name=":4" />
Gentle stretching and massage, putting some pressure on the affected leg by walking or standing, or taking a warm bath or shower may help to end the cramp.<ref name="nytimes-ray">{{cite news |last=Ray |first=C. Claiborne |date=2009-06-09 |title=Q & A – A Charley Horse in Bed |url=https://www.nytimes.com/2009/06/09/health/09qna.html |url-status=live |archive-url=https://web.archive.org/web/20130407063441/http://www.nytimes.com/2009/06/09/health/09qna.html |archive-date=2013-04-07 |access-date=2009-06-09 |work=The New York Times}}</ref> If the cramp is in the calf muscle, dorsiflexing the foot (lifting the toes back toward the shins) will stretch the muscle and provide almost immediate relief. There is limited evidence supporting the use of magnesium, calcium channel blockers, carisoprodol, and vitamin B<sub>12</sub>.<ref name=":0" />
== Causes == {{See also|Exercise-associated muscle cramps}}
Skeletal muscle cramps may be caused by muscle fatigue or a lack of electrolytes{{Citation needed|date=March 2023}} such as sodium (a condition called hyponatremia), potassium (called hypokalemia), or magnesium (called hypomagnesemia<ref>{{Cite journal|last1=Gragossian|first1=Alin|last2=Bashir|first2=Khalid|last3=Friede|first3=Rotem|date=September 6, 2020|title=Hypomagnesemia|url=https://www.ncbi.nlm.nih.gov/books/NBK500003/|access-date=October 14, 2020|website=National Center for Biotechnology Information (NCBI)|pmid=29763179|quote="Hypomagnesemia is an electrolyte disturbance caused when there is a low level of serum magnesium [...] in the blood"}}</ref>). Some skeletal muscle cramps do not have a known cause.<ref name=":1" /> Motor neuron disorders (e.g., amyotrophic lateral sclerosis), metabolic disorders (e.g., liver failure), some medications (e.g., diuretics and inhaled beta‐agonists), and haemodialysis may also cause muscle cramps.<ref name=":1" />
Causes of cramping include<ref>[http://www.medicinenet.com/muscle_cramps/page2.htm#2whatare Muscle Cramps Symptoms, Causes, Treatment – Do all muscle cramps fit into the above categories on MedicineNet] {{webarchive|url=https://web.archive.org/web/20080824152442/http://www.medicinenet.com/muscle_cramps/page2.htm |date=2008-08-24 }}. Medicinenet.com. Retrieved on 2011-02-13.</ref> hyperflexion, hypoxia, exposure to large changes in temperature, dehydration, or low blood salt. Muscle cramps can also be a symptom or complication of pregnancy; kidney disease; thyroid disease; hypokalemia, hypomagnesemia, or hypocalcaemia (as conditions); restless legs syndrome; varicose veins;<ref>Bergan J. The Vein Book, Hardcover text, Editor Bergan J, 2007. {{isbn|9780195399639}}</ref> and multiple sclerosis.<ref name="test2">{{Cite web|url=http://www.webmd.com:80/hw-popup/muscle-cramps|archive-url=https://web.archive.org/web/20071015073632/http://www.webmd.com/hw-popup/muscle-cramps|title=Muscle cramps|archive-date=October 15, 2007|website=www.webmd.com}}</ref>
As early as 1965, researchers observed that leg cramps and restless legs syndrome can result from excess insulin, sometimes called hyperinsulinemia.<ref>{{cite journal|last1=Roberts|first1=HJ|title=Spontaneous Leg Cramps and "restless Legs" Due to Diabetogenic Hyperinsulinism: Observations on 131 Patients|journal=Journal of the American Geriatrics Society|volume=13|issue=7|pages=602–38|year=1965|pmid=14300967|doi=10.1111/j.1532-5415.1965.tb00617.x|s2cid=28096190}}</ref>
=== Nocturnal leg cramps === {{see also|Charley horse}} Leg cramps might occur during the night or less commonly while resting. These are involuntary muscle contractions that occur in the calves, soles of the feet, or other muscles in the body. The duration is variable, with cramps lasting anywhere from a few seconds to several minutes. Muscle soreness may remain after the cramp itself ends. These cramps are more common in older people.<ref name="mayo">{{Cite web|url=https://www.mayoclinic.org/symptoms/night-leg-cramps/basics/definition/sym-20050813|archive-url=https://web.archive.org/web/20110923231142/http://www.mayoclinic.com/health/night-leg-cramps/MY00410|title=Night leg cramps|archive-date=September 23, 2011|website=Mayo Clinic}}</ref> They happen quite frequently in teenagers and some people while exercising at night. Besides being painful, a nocturnal leg cramp can cause much distress and anxiety.<ref>{{cite journal|last=Weiner|first=Israel H|title=Nocturnal Leg Muscle Cramps|year=1980|volume=244|issue=20|pages=2332–3|url=http://jama.ama-assn.org/content/244/20/2332.short|journal=JAMA|doi=10.1001/jama.1980.03310200066033|pmid=7431559|access-date=26 October 2011|url-status=live|archive-url=https://web.archive.org/web/20101228162905/http://jama.ama-assn.org/content/244/20/2332.short|archive-date=28 December 2010|url-access=subscription}}</ref> The precise cause of these cramps is unclear. Potential contributing factors include dehydration, low levels of certain minerals (magnesium, potassium, calcium, and sodium, although the evidence has been mixed),<ref>{{cite journal |vauthors=Schwellnus MP, Nicol J, Laubscher R, Noakes TD |title=Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners |journal=Br J Sports Med |year=2004 |volume=38 |issue=4 |pages=488–492 |doi=10.1136/bjsm.2003.007021|pmid=15273192 |pmc=1724901 }}</ref><ref name="pmid16015122">{{cite journal | vauthors = Sulzer NU, Schwellnus MP, Noakes TD | title = Serum electrolytes in Ironman triathletes with exercise-associated muscle cramping | journal = Med Sci Sports Exerc | volume = 37 | issue = 7 | pages = 1081–5 | date = July 2005 | pmid = 16015122 | doi = 10.1249/01.mss.0000169723.79558.cf| s2cid = 12582883 | doi-access = free }}</ref><ref name=":0"/> and reduced blood flow through muscles attendant in prolonged sitting or lying down. Nocturnal leg cramps (almost exclusively calf cramps) are considered "normal" during the late stages of pregnancy.<ref>{{cite web |url=https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/expert-answers/leg-cramps-during-pregnancy/faq-20057766 |title=What causes leg cramps during pregnancy, and can they be prevented? |vauthors = Wick M |website=Mayo Clinic |access-date=2018-04-03 }}</ref>
A lactic acid buildup around muscles can trigger cramps; however, they happen during anaerobic respiration when a person is exercising or engaging in an activity where the heartbeat rises. Medical conditions associated with leg cramps are cardiovascular disease, hemodialysis, cirrhosis, pregnancy, and lumbar canal stenosis. Differential diagnoses include restless legs syndrome, claudication, myositis, and peripheral neuropathy. All of them can be differentiated through careful history and physical examination.<ref name=":0">{{cite journal |url=http://www.aafp.org/afp/2012/0815/p350.html |title=Nocturnal Leg Cramps |journal=American Family Physician |vauthors=Allen RE, Kirby KA |year=2012 |volume=86 |issue=4 |pages=350–355 |pmid=22963024 |url-status=live |archive-url=https://web.archive.org/web/20160329134250/http://www.aafp.org/afp/2012/0815/p350.html |archive-date=2016-03-29 }}</ref>
===Treatment induced=== Various medications may cause nocturnal leg cramps:<ref name=":0"/><ref name="pmid22157068">{{cite journal | vauthors = Garrison SR, Dormuth CR, Morrow RL, Carney GA, Khan KM | title = Nocturnal leg cramps and prescription use that precedes them: a sequence symmetry analysis | journal = Arch. Intern. Med. | volume = 172 | issue = 2 | pages = 120–6 | date = January 2012 | pmid = 22157068 | doi = 10.1001/archinternmed.2011.1029 | doi-access = }}</ref> * Diuretics, especially potassium-sparing * Intravenous (IV) iron sucrose * Conjugated estrogens * Teriparatide * Naproxen * Raloxifene * Long-acting adrenergic beta-agonists (LABAs) * Hydroxymethylglutaryl-coenzyme A reductase inhibitors (HMG-CoA inhibitors or statins)
Statins may sometimes cause myalgia and cramps among other possible side effects. Raloxifene (Evista) is a medication associated with a high incidence of leg cramps. Additional factors, that increase the probability of these side effects, are physical exercise, age, history of cramps, and hypothyroidism. Up to 80% of athletes using statins experience significant adverse muscular effects, including cramps;<ref> {{cite journal |vauthors=Sinzinger H, O'Grady J |title=Professional athletes suffering from familial hypercholesterolaemia rarely tolerate statin treatment because of muscular problems |journal=Br J Clin Pharmacol |volume=57 |issue=4 |pages=525–8 |year=2004 |pmid=15025753 |doi=10.1111/j.1365-2125.2003.02044.x |pmc=1884475}}</ref> the rate appears to be approximately 10–25% in a typical statin-using population.<ref> {{cite journal |vauthors=Bruckert E, Hayem G, Dejager S, Yau C, Bégaud B |title=Mild to moderate muscular symptoms with high-dosage statin therapy in hyperlipidemic patients—the PRIMO study |journal=Cardiovasc Drugs Ther |volume=19 |issue=6 |pages=403–14 |year=2005 |pmid=16453090 |doi=10.1007/s10557-005-5686-z|s2cid=24525127 }}</ref><ref> {{cite journal |title=Statin-induced apoptosis and skeletal myopathy |journal=Am. J. Physiol., Cell Physiol. |volume=291 |issue=6 |pages=C1208–12 |year=2006 |pmid=16885396 |doi=10.1152/ajpcell.00226.2006 |author=Dirks, A. J. |last2=Jones |first2=KM|s2cid=13313618 }}</ref> In some cases, adverse effects disappear after switching to a different statin; however, they should not be ignored if they persist, as they can, in rare cases, develop into more serious problems. Coenzyme Q10 supplementation can help avoid some statin-related adverse effects, but currently, there is not enough evidence to prove its effectiveness in avoiding myopathy or myalgia.<ref>{{cite journal |vauthors=Lamperti C, Naini AB, Lucchini V |title=Muscle coenzyme Q10 level in statin-related myopathy |journal=Arch. Neurol. |volume=62 |issue=11 |pages=1709–12 |year=2005 |pmid=16286544 |doi=10.1001/archneur.62.11.1709|display-authors=etal|doi-access= }}</ref>
==Treatment== Stretching, massage, and drinking plenty of liquids may help treat simple muscle cramps.<ref name="PMID 8784961">{{cite journal | pmid = 8784961 | volume=21 | issue=6 | title=Exercise-induced muscle cramp. Proposed mechanisms and management | date=June 1996 | author=Bentley S | pages=409–20 | journal=Sports Med | doi=10.2165/00007256-199621060-00003| s2cid=24366112 }}</ref>
===Medication=== While quinine was a traditional treatment for nocturnal leg cramps, it is no longer recommended due to potential fatal hypersensitivity reactions and thrombocytopenia. Arrhythmias, cinchonism, and hemolytic uremic syndrome can also occur at higher dosages.<ref name=":0" />
Magnesium is commonly used to treat muscle cramps. Moderate-quality evidence indicates that magnesium is not effective for treating or preventing cramps in older adults.<ref name=":1" /> It is not known if magnesium helps with cramps due to pregnancy, liver cirrhosis, other medical conditions, or exercise.<ref name=":1" /> Oral magnesium treatment does not appear to have significant major side effects, however, it may be associated with diarrhea and nausea in 11–37% of people who use this medicine.<ref name=":1" />
With exertional heat cramps due to electrolyte abnormalities (primarily potassium loss and not calcium, magnesium, and sodium), appropriate fluids and sufficient potassium improve symptoms.<ref name="pmid12801207">{{cite journal|vauthors=Bergeron MF|date=March 2003|title=Heat cramps: fluid and electrolyte challenges during tennis in the heat|journal=J Sci Med Sport|volume=6|issue=1|pages=19–27|doi=10.1016/S1440-2440(03)80005-1|pmid=12801207}}</ref> Vitamin B complex, naftidrofuryl, lidocaine, and calcium channel blockers may be effective for muscle cramps.<ref name=Katzberg>{{cite journal |vauthors=Katzberg HD, Khan AH, So YT |title=Assessment: Symptomatic treatment for muscle cramps (an evidence-based review): Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology |journal=Neurology |volume=74 |issue=8 |pages=691–6 |year=2010 |pmid=20177124 |doi=10.1212/WNL.0b013e3181d0ccca|doi-access=free }}</ref>
==Prevention== Adequate conditioning, stretching, mental preparation, hydration, and electrolyte balance are likely helpful in preventing muscle cramps.<ref name="PMID 8784961"/>
== See also == * Spasm * Writer's cramp
==References== {{Reflist}}
== External links == * [http://www.medicinenet.com/muscle_cramps/article.htm Muscle Cramps (of Skeletal Muscles)]
{{Medical resources | DiseasesDB = 3151 | ICD10 = {{ICD10|R|25|2|r|25}} | ICD9 = {{ICD9|729.82}} | ICDO = | OMIM = | MedlinePlus = 003193 | eMedicineSubj = | eMedicineTopic = | MeshID = D009120 }} {{Myopathy}} {{Nervous and musculoskeletal system symptoms and signs}} {{Underwater diving|divmed}}
Category:Muscular disorders Category:Symptoms and signs: musculoskeletal system