A cramp is the abrupt spasm of muscle and associated tendon resulting in pain and often the mal-position of the anatomy associated with that muscle and tendon such as hyper-flexion, hyper-extension or contracture of the toes. Muscle cramps of the lower leg and foot can be broken down into three main categories; ischemic, metabolic and biomechanical.
Ischemia is the term used to describe insufficient circulation of blood to tissue. When blood flow to a muscle is inadequate and the muscle becomes ishemic, the muscle will cramp. The pain that accompanies the cramp prompts us to walk or rub the cramp which in turn results in increased circulation. Ischemic cramping typically occurs at night and is called nocturnal claudication. Muscle cramping due to ischemia can also occur with exercise and is called intermittent claudication. Doctors will often ask patients with poor circulation to describe how far they can walk before the cramp and will use this as a measure of their peripheral vascular disease.
The most common metabolic deficiency that causes foot and leg cramping is an imbalance is a group of chemicals called electrolytes (sodium, potassium, calcium, magnesium, chloride). Sodium and potassium are the two primary electrolytes that regulate muscle function and subsequently may contribute to muscle cramping. Low potassium (hypokalemia) and low sodium (hyponatremia) can result from over exercise, use of diuretics (water pills) and renal disease. A balance between potassium and sodium is imperative for normal muscle function. Lack of either or both of these two electrolytes will result in muscle dysfunction and muscle cramping.
Biomechanics is the science of how the body moves. The biomechanics of walking and running is quite complex. The act of walking is a finely tuned symphony of brain impulses and muscle contraction. If an imbalance is found between two apposing muscle groups resulting in one group being forced work beyond its' capacity, muscle cramping may occur. As with ischemic cramping, we will be forced to walk off a biomechanical muscle cramp. Biomechanical cramping can be managed with a regular stretching program, supportive shoes and arch supports.
In athletes and younger patients leg cramps are common following a long day of activity. Muscle continues to have oxygen and metabolic needs for a number of hours following activity. In athletes and growing children cramping is simply a symptom that enables the muscle to get the electrolytes and oxygen that it needs. In older, less active patients, cramping can be a common symptom of peripheral arterial disease (PAD). Testing for PAD is very simple and can be performed in a vascular testing lab (office based) in a matter of minutes.
Causes and contributing factors
Contributing factors to metabolic cramping include excessive perspiration, excessive fluid intake and use of diuretics. Contributing factors to ischemic cramping include age, history of smoking or smokeless tobacco use and high levels of cholesterol.
The differential diagnosis for cramping includes;
Treatment of foot cramps depend upon whether the cramps are metabolic or ischemic. Metabolic cramping due to diuretic use should be evaluated by your doctor. Cramping due to excessive fluid intake can be corrected with sports drinks such as Gatorade that will replenish sodium and potassium. Cramping due to excessive perspiration and exercise can also be treated with sports drinks or supplemental sodium and potassium intake. Ischemic cramping should be evaluated by your doctor to determine the level and severity of peripheral arterial disease.
When to contact your doctor
Cramping due to diuretic use may be life threatening and should always be evaluated by your family doctor. Cramping secondary to exercise or excessive fluid intake that does not respond to home care should also be evaluated by your podiatrist or family doctor. All cases of cramping due to peripheral arterial disease should be evaluated by your podiatrist or family doctor.
References are pending.
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Cite this article as: Oster, Jeffrey. Cramping of the Foot and Leg. http://www.myfootshop.com/article/cramping-of-the-foot-and-leg
Most recent article update: December 23, 2015.
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