Leg cramps: causes

Leg cramps occur when a skeletal muscle involuntarily contracts and tenses to its maximum in a sudden, often very painful but brief spasm. The calf muscles at the back of the lower leg are most commonly affected, as well as the muscles of the foot, the posterior thigh muscle above the hamstring, or the quadriceps muscle at the front of the thigh. [1]

Epidemiology

Statistics show that nearly six older adults out of ten often have leg cramps, primarily at night, with three out of four cases occurring during sleep.

That said, leg cramps in men occur almost three times less frequently than cramps in women.

According to some estimates, peripheral artery disease (lower extremity blood vessels) affects nearly 10% of people over the age of 55.

Febrile seizures affect about 2-5% of children under the age of five.

Causes of the leg cramps

According to medical experts, in many cases, the causes of leg cramps are unknown and such cramps are called idiopathic cramps.

Identifiable causes include, first and foremost, excessive muscle strain and overstretching of muscle fibers in the calf or posterior thigh (hamstring area) with the occurrence of leg cramps after exercise; severe leg cramps develop after running - intense painful contractions that usually occur with fatigue and/or overheating. Local cramps are observed when individual muscle groups are overstressed due to the performance of frequently repeated rapid movements, which, in particular, explains leg cramps during orgasm during sex.

Muscle cramps in the lower limbs or krampy, not related to increased physical activity, can be due to many different causes: night leg cramps are caused by an uncomfortable body position, cooling or overheating during sleep, a bed that is too soft or too hard. Leg cramps at night are more common in people over 50 than in younger people, and more common in overweight people than in thin people.

The main cause of leg cramps in the morning is considered to be prolonged awkward positioning of the legs during sleep, with blood vessels being squeezed.

Tonic leg cramps in the daytime occur when a person walks for a long time, stands on a hard surface for a long time or has to stay in a sitting position for a long time. Those who suffer from flat feet or wear shoes that are too narrow, and high heels only increase the risk of muscle cramps in the calf and foot.

Many people get leg cramps in the water - pool or natural bodies of water. What causes leg cramps when swimming? Experts attribute them to the bending of the sole of the foot during swimming - when all the muscles of the leg form a rigid line from the shin to the toes, which allows you to move in the water. But holding this position overstretches the muscles and can cause them to contract involuntarily - severe leg cramps. In addition, in cold water, due to the compression of blood vessels, the rate of blood circulation decreases, and with insufficient oxygen supply to muscle tissues, neuromuscular conduction is impaired.

These are the most common benign types of leg cramps.

Read also - Why your toes cramp up

However, there are many conditions and pathologies in which cramping of the left or right leg, or cramping of both legs, is one of their signs. That is, they are considered secondary, and in such cases, the causes of leg cramps are related to specific conditions or diseases.

Leg cramps after surgery are considered a side effect of pain medications for local anesthesia and general anesthesia.

Cramps in a leg fracture occur when the bone traumatically damages the surrounding muscle fibers and compresses the motor nerve endings.

As a result of the toxic effects of ethanol on the CNS with inhibition of nerve signals, reduction of electrolyte levels due to dehydration, and impaired regional blood circulation, leg cramps occur after alcohol ingestion (especially by chronic alcoholics). [2]

Muscle spasms in the form of cramps may occur due to iatrogenic causes: with prolonged use of such drugs as selective beta-adrenoreceptor agonists (bronchodilators), antidepressants of the SSRI group, barbiturates, lithium, statins, nicotinic acid, hormonal contraceptives, cytostatics (anticancer agents). After prolonged use of diuretics, that is, after diuretics leg cramps are associated with increased excretion of magnesium from the body and the development of hypomagnesemia.

Leg cramps and leg cramps in pregnancy (especially in late pregnancy) - due to a decrease in the amount of magnesium and calcium in the blood - hypocalcemia. Foot cramps at night are common in the third trimester of pregnancy due to the pressure of the uterus on the veins and worsening of blood outflow; cramps in the legs and groin are not uncommon. For more information, see. - Why Leg Cramps in Pregnancy. Leg cramps after childbirth are the result of compression of blood vessels and tension in the muscles of the pelvis and thighs.

Leg cramps in a child can occur when the body is dehydrated (with vomiting and/or diarrhea); with avitaminosis; due to thyroid problems. In febrile conditions associated with infectious diseases, children under five years of age have a combination of leg cramps and fever. Such cramps are called febrile cramps.

There is an increased risk of leg cramps with parasites - parasitic invasions: ascaridosis, trichinellosis, echinococcosis.

Frequent leg cramps in the elderly may be due to natural shortening of tendons (due to fluid loss) and decreased elasticity of muscle fibers; painful cramps in the calves (at rest) and tibialis anterior (after walking) may also be noted in old age, which are symptoms of idiopathic leg neuropathy.

In addition to hypodynamia and age-related degenerative changes of a muscular nature, leg cramps in people over 50 occur due to leg circulation disorders. A common condition with poor blood circulation associated with atherosclerosis or venous insufficiency - leg cramps when walking with the appearance of painful sensations and even temporary lameness. In the first case, poor blood circulation in the arteries of the legs in old age often correlates with problems of atherosclerotic changes in cerebral vessels, and the first signal of the risk of future development of such a dangerous condition as ischemic stroke, experts consider sleep disorders, persistent headaches, frequent dizziness and leg cramps.

People who complain of cramps and cold feet, as well as the fact that at rest their legs hurt, cramps in the evenings, should be examined for peripheral leg vascular disease (which develops due to cholesterol deposits in the arteries of the lower extremities).

In the second case, these are leg cramps in varicose veins - varicose dilation of superficial veins, which is accompanied by deterioration of venous blood outflow from the legs and a violation of muscle trophics. These types of cramp usually affect the muscles of the calf and quadriceps muscle of the thigh, which are stretched through two joints, that is, leg cramps above the knee, thigh are noted.

Complaints of cramps and cold feet are associated with endocrinologic problems: the presence of diabetes or hypothyroidism.

If there are symptoms such as cramps and numbness in the legs (paresthesia), it is suspected that this is the result of compression of nerve endings, and the culprit may be osteochondrosis in the lumbar region with the development of radiculopathy.

The most common reason for such leg cramps in diabetes is neurological disorders - diabetic neuropathy. Another causative risk factor for cramps in diabetics is angiopathy of the extremities, which develops due to a decrease in the intensity of capillary and arterial blood flow in the legs.

If a patient complains of cramping and burning in the legs, it may indicate peripheral neuropathy - a disorder of nerve impulse transmission, noted in diabetes, cancer, nutritional disorders, infectious inflammation, chemotherapy of malignant tumors. In healthy people, burning in the legs after cramps is associated with lactoacidosis, i.e. Accumulation of lactic acid in the blood - a by-product of glucose breakdown, the breakdown of which (for energy) occurs during intense exercise.

Leg and back cramps, accompanied by numbness and tingling in the leg, can give intervertebral or intervertebral hernia (as a result of dystrophic changes in the muscles and violations of their innervation). And leg cramps with herniated discs are associated with pinched nerves or stenosis of the lumbar spine; nerve root compression is considered by neurologists as one of the predisposing factors for night leg cramps.

If in addition to the occurrence of cramping, legs fail, it is not excluded that the patient has such pathologies as multiple sclerosis (autoimmune disease of the nervous system, in which the nerve branches lose their myelin sheath and muscle function is impaired with the development of spasticity) or motoneuron disease.

Accompanied by involuntary contractions of muscle fibers - fasciculations - peripheral flaccid paresis, i.e. A decrease in muscle tone in one or both legs, may indicate neurological problems such as amyotrophic lateral sclerosis or damage to motor neurons in the spinal cord (motor neuropathy).

The list, which includes the most likely causes of leg and arm cramps, includes:

• Parathyroid gland insufficiency - hypoparathyroidism, due to which the level of calcium in the blood decreases;
• A chronic form of renal failure resulting in increased phosphate levels in the blood;
• potassium deficiency;
• dehydration or lack of fluids;
• epilepsy (with tonic-clonic seizures);
• alcoholic delirium;
• Anemia (iron deficiency or hemolytic);
• MS;
• hypoglycemia;
• infections, primary brain tumors or aneurysms;
• side effects of medications.

Risk factors

Summarizing the etiology of leg cramps, physicians call the following risk factors for their occurrence:

• muscle strain in the lower extremities;
• sedentary lifestyle and obesity;
• musculoskeletal injuries;
• age-related degenerative changes in muscle tissues and tendons;
• dehydration (dehydration) associated with both inadequate fluid intake and excessive sweating;
• alcoholism;
• flat feet, wearing the wrong shoes;
• low levels of electrolytes (magnesium, calcium, or potassium) in the blood;
• Vitamin deficiency (B6, D, E);
• pregnancy;
• high blood cholesterol;
• The presence of neurological or metabolic disorders;
• Endocrine diseases (diabetes mellitus, hypothyroidism, hypoparathyroidism);
• Neuromuscular disorders, particularly neuropathy, myopathy, and motoneuron disease;
• spinal nerve compression;
• cirrhosis;
• chronic kidney failure and the effects of kidney dialysis (during which too much fluid is removed from the body, which disturbs the balance of electrolytes);
• Parkinson's, Huntington's;
• the use of certain medications.

Older people have a higher risk of leg cramps: closer to the age of 50, the loss of muscle mass begins, and - if a person leads a sedentary lifestyle - this process progresses.

Pathogenesis

The biochemistry of muscle contraction is very complex, and how disturbances in the transmission of nerve impulses occur is still not entirely clear. The mechanism of the development of lower limb cramps at night, i.e. Their pathogenesis, is explained by the fact that cramps occur when the calf muscle - in the sleeping position with knees half-bent and feet pointing downwards - is in a shortened position and can be spasmed at any attempt to change position.

In addition, prolonged periods in the same position during sleep are accompanied by slowed blood circulation and reduced oxygen levels in muscle tissues, which leads to cramps.

There are several versions of the pathogenesis of physical exertion cramps. It is traditionally believed that such cramps are caused by dehydration, electrolyte imbalances (including magnesium, potassium and calcium), lactic acid accumulation or low cellular energy levels (in the form of ATP). For example, if the body lacks magnesium, the contact between afferent and efferent neurons in neuromuscular cholinergic synapses is disturbed: the channels of presynaptic membranes stop opening, and this leads to an increase in the level of free acetylcholine, a mediator of nerve impulses in muscles, in the synaptic gap.

It is assumed that the mechanism of convulsions is associated with increased activity of the neuromuscular reflex arc of the CNS due, on the one hand, to the inhibitory effect exerted by the Golgi tendon organs and, on the other hand, to hyperactivation of muscle spindles. [3]

Symptoms of the leg cramps

Leg cramps occur suddenly, but some patients claim to be able to feel the first signs of developing cramp in the form of fascioculations - twitching of muscle fibers.

The main symptoms of a cramp are a sudden tension, i.e. Contraction of a muscle, which causes pain. The cramped muscle becomes hard (rigid) and cannot be relaxed by willpower.

The leg cramp does not let go for 20-30 seconds or several minutes; the longest lasting cramp is of the quadriceps femoris muscle.

After the cramp goes away, you may feel a nagging pain in the muscle for a while.

Diabetes cramps involve the muscles of the lower legs and feet and are accompanied by paresthesia (or hyperesthesia), and quite pronounced pain in the leg after a cramp with the inability to move normally can be observed for several hours. [4]

Complications and consequences

In cases of leg cramps after exercise, there are no negative health or medical consequences.

Leg cramps at night can impair quality of life by upsetting sleep.

It's not hard to guess the dangers of leg cramps, which can catch a person driving a car or floating in a river...

The involuntary muscle contractions themselves are not related to the effects of diseases of which lower limb cramps are one of the symptoms. Although many of these conditions, for example, peripheral vascular disease of the legs, are

Potentially disabling.

Diagnostics of the leg cramps

Medically, primary benign cramps are rarely a cause for concern, and diagnosis is required if non-exercise-related involuntary muscle contractions occur persistently.

Required tests for leg cramps: general and biochemical blood tests; for sugar, creatine kinase, lactate dehydrogenase, electrolytes, parathormone, specific antibodies to helminths.

Instrumental diagnostics are also performed:

• muscle research (electromyography, ultrasound);
• Doppler and ultrasound of leg vessels, angiography.
• MRI of the spinal cord is performed if there is focal muscle weakness or neurologic signs.

Differential diagnosis

Differential diagnosis is very important because some disorders cause symptoms that resemble seizures: dystonia, spasticity (including myotonia), fasciculations, essential tremor, myokymia, tetany. Also defined in epilepsy are focal or partial leg seizures, and clonic seizures characteristic of epilepsy and hyperkinesis.

Leg cramps are different from a condition called restless leg syndrome.

Often the exact cause of leg cramps is difficult to determine, and they may be due to a combination of different factors.

For example, the low-carbohydrate Kremlin diet, which, like the Atkins diet, is a keto diet, removes fluid from the body. As a result, those who follow this weight loss diet (eating a lot of protein and fats) not only get constipation, but also leg cramps - as magnesium absorption in the intestines is reduced.