What are leg cramps?
A leg cramp is a pain that comes from a muscle in the leg. It is due to a muscle spasm, which is when a muscle contracts too hard. It usually occurs in one of the calf muscles, below and behind a knee. The small muscles of the feet are sometimes affected.

Who gets leg cramps?
Many people have an occasional leg cramp. However, they occur frequently in some people. They are more common in older people.

About one in three people over the age of 60, and about half of people over the age of 80 have regular leg cramps. About four in 10 people who have leg cramps have at least three per week. They occur every day in some cases.

What causes leg cramps?
Unknown cause (idiopathic leg cramps)
In most cases the cause is not known. One theory is that cramps occur when a muscle that is already in a shortened position is stimulated to contract.

As the muscle is already shortened, to contract further may cause the muscle to go into spasm.

This commonly happens at night in bed as the natural position we lie in is with the knees slightly bent (flexed), and with feet pointing slightly downwards. In this position the calf muscle is relatively shortened and prone to cramps. This theory explains why stretching exercises may cure the problem.

Secondary causes
In some cases, the cramps may be a symptom of another condition or problem. For example:
Some medicines can cause cramps as a side-effect, or make cramps occur more often. These include:
* diuretics ('water tablets'), nifedipine, cimetidine, salbutamol, terbutaline, lithium, clofibrate, penicillamine, morphine (withdrawal), phenothiazines, and nicotinic acid.
* Over-exertion of muscles.
* Dehydration. 
* Conditions that cause alterations in the balance of salts in the bloodstream (such as a high or low sodium or potassium level). 
* Some people who have renal (kidney) dialysis get leg cramps.
* Pregnancy - usually in the later stages.
* An untreated under-active thyroid gland. 
* Peripheral vascular disease (narrowing of the leg arteries, which causes poor circulation). 
* Cirrhosis of the liver is a rare cause. 
* Lead poisoning. 
* Sarcoidosis. 
* Rare disorders of nerves. 
* Excess alcohol.

With the above conditions the cramps would just be one of various other symptoms.

Therefore, if you are otherwise well, and have no other unexplained symptoms, then the leg cramps are likely to be idiopathic (unknown cause) and not due to a secondary cause.

Leg cramps are different to a condition called restless legs syndrome. In this condition the legs can be uncomfortable, you feel creeping sensations in the legs, and it is relieved by walking about.

prof@cardiacclinic.co.bw