| Cramp | |
|---|---|
| Symptoms | sudden muscle pain and a paralysis-like immobility |
| Treatment | quinine, stretching, massage, and drinking liquids |
Acramp is a sudden, involuntary, painfulskeletalmuscle contraction[1][2] or overshortening associated with electrical activity;[3] while generally temporary and non-damaging, they can cause significantpain and aparalysis-like immobility of the affected muscle. A cramp usually goes away on its own over several seconds or (sometimes) minutes.[4] Cramps are common and tend to occur at rest, usually at night (nocturnal leg cramps).[2][5] They are also often associated withpregnancy,physical exercise or overexertion, and age (common in older adults); in such cases, cramps are calledidiopathic because there is no underlying pathology. In addition to those benign conditions cramps are also associated with manypathological conditions.[2][6]
Cramp definition is narrower than the definition of musclespasm: spasms include any involuntary abnormal muscle contractions, while cramps are sustained and painful.[1][7] True cramps can be distinguished from other cramp-like conditions. Cramps are different frommuscle contracture, which is also painful and involuntary, but which is electrically silent. The main distinguishing features of cramps fromdystonia 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.[2]Restless leg syndrome is not considered the same as muscle cramps and should not be confused with rest cramps.[6]
Skeletal muscle cramps may be caused bymuscle fatigue or a lack ofelectrolytes[citation needed] such assodium (a condition calledhyponatremia),potassium (calledhypokalemia), ormagnesium (calledhypomagnesemia[8]). Some skeletal muscle cramps do not have a known cause.[6] Motor neuron disorders (e.g.,amyotrophic lateral sclerosis),metabolic disorders (e.g.,liver failure), some medications (e.g.,diuretics and inhaledbeta‐agonists), andhaemodialysis may also cause muscle cramps.[6]
Causes of cramping include[9]hyperflexion,hypoxia, exposure to large changes in temperature, dehydration, orlow blood salt. Muscle cramps can also be a symptom or complication ofpregnancy;kidney disease;thyroid disease;hypokalemia,hypomagnesemia, orhypocalcaemia (as conditions);restless legs syndrome;varicose veins;[10] andmultiple sclerosis.[11]
As early as 1965, researchers observed that leg cramps and restless legs syndrome can result from excessinsulin, sometimes calledhyperinsulinemia.[12]
Under normal circumstances,skeletal muscles can be voluntarily controlled. Skeletal muscles that cramp the most often are thecalves,thighs, andarches of the foot, and in North America are sometimes called a "Charley horse" or a "corky". Such cramping is associated with strenuous physical activity and can be intensely painful; however, it can occur while inactive and relaxed. Around 40% of people who experience skeletal cramps are likely to endure extreme muscle pain and may be unable to use the entire limb that contains the "locked-up" muscle group. It may take up to a week for the muscle to return to a pain-free state, depending on the person's fitness level, age, and several other factors.[citation needed]
Nocturnal leg cramps are involuntary muscle contractions that occur in thecalves,soles of the feet, or other muscles in the body during the night or (less commonly) while resting. The duration of nocturnal leg cramps 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.[13] They happen quite frequently in teenagers and some people while exercising at night. Besides being painful, a nocturnal leg cramp can cause muchdistress andanxiety.[14] The precise cause of these cramps is unclear. Potential contributing factors includedehydration, low levels of certain minerals (magnesium,potassium,calcium, andsodium, although the evidence has been mixed),[15][16][17] 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.[18] They can, however, vary in intensity from mild to extremely painful.[citation needed]
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 includerestless legs syndrome,claudication,myositis, andperipheral neuropathy. All of them can be differentiated through careful history and physical examination.[17]
Gentlestretching andmassage, putting some pressure on the affected leg by walking or standing, or taking a warm bath or shower may help to end the cramp.[19] 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, andvitamin B12.[17]
Quinine is no longer recommended for the treatment of nocturnal leg cramps due to potential fatal hypersensitivity reactions andthrombocytopenia.Arrhythmias,cinchonism, andhemolytic uremic syndrome can also occur at higher dosages.[17]
Various medications may cause nocturnal leg cramps:[17][20]
Statins may sometimes causemyalgia 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, andhypothyroidism. Up to 80% of athletes using statins experience significant adverse muscular effects, including cramps;[21] the rate appears to be approximately 10–25% in a typical statin-using population.[22][23] 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.[24]
Stretching, massage, and drinking plenty of liquids may help treat simple muscle cramps.[25]
The antimalarial drugquinine is a traditional treatment that may be slightly effective for reducing the number of cramps, the intensity of cramps, and the number of days a person experiences cramps. Quinine has not been shown to reduce the duration (length) of a muscle cramp.[6] Quinine treatment may lead to hematologic and cardiac toxicity. Due to its low effectiveness and negative side effects, its use as a medication for treating muscle cramps is not recommended by the FDA.[26]
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.[6] It is not known if magnesium helps with cramps due to pregnancy, livercirrhosis, other medical conditions, or exercise.[6] 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.[6]
With exertional heat cramps due toelectrolyte abnormalities (primarily potassium loss and not calcium, magnesium, and sodium), appropriate fluids and sufficient potassium improve symptoms.[27]Vitamin B complex,naftidrofuryl,lidocaine, andcalcium channel blockers may be effective for muscle cramps.[26]
Adequate conditioning, stretching, mental preparation, hydration, and electrolyte balance are likely helpful in preventing muscle cramps.[25]
Hypomagnesemia is an electrolyte disturbance caused when there is a low level of serum magnesium [...] in the blood
