Calcium makes up 1 percent to 2 percent of adult body weight. While over 99 percent of calcium is found in teeth and bones, the rest is present in blood, muscles and other tissues. Calcium deficiency is commonly caused by vitamin D deficiency or by dysfunction or surgical removal of the parathyroid glands. Deficiency of this mineral causes a variety of symptoms, depending on its severity and how quickly it develops. When it develops rapidly, it may cause such problems as muscle spasms, seizures and abnormal heart rhythms. People with chronic calcium deficiency may have no symptoms, or they may develop cataracts, changes in behavior, or problems with their bones, skin and teeth.
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When deficient in calcium, muscles and nerves become abnormally excitable -- known as neuromuscular irritability. When calcium deficiency is mild, numbness or tingling around the mouth and fingertips may occur. More severe deficiency can cause tetany, characterized by involuntary muscle twitching, cramps and spasms. Tetany can occur spontaneously. It can also be elicited by a test, in which a blood pressure cuff on the upper arm is inflated to reduce blood flow to the hand. If this causes hand spasms, it is called the Trousseau sign. This sign is present in 94 percent of people with low blood levels of calcium and only 1% of those with normal calcium levels, according to a June 2008 article in the “British Medical Journal."
Other Neurologic Symptoms
Calcium deficiency that develops quickly may cause seizures. When calcium deficiency is long-standing, it can cause a variety of other problems in the nervous system. Headaches can occur due to increased pressure within the head. There may be swelling of part of the optic nerve -- the nerve that connects the eye to the brain. This can cause blurry or double vision or loss of peripheral vision. Cataracts may develop and they can also cause blurry vision. Chronic calcium deficiency can likewise cause neuropsychiatric symptoms, such as depression, changes in personality and problems with thinking, sometimes as severe as dementia.
The heart contains an electrical conduction system, which sends signals to the heart muscles so they can pump blood to the rest of the body. Calcium deficiency can cause abnormalities in this electrical conduction system, leading to abnormal heart rhythms. Symptoms of an abnormal heart rhythm may include fainting or a feeling that the heart is skipping beats or beating too fast. Calcium deficiency can also impair the ability of the heart muscles to contract and pump blood, leading to heart failure. Symptoms of heart failure include shortness of breath or swelling of the legs. Low blood pressure may be present as well.
Other Signs and Symptoms
Long-standing calcium deficiency can affect other body areas as well. Skin can become dry or itchy, and eczema or psoriasis may develop. Dry, brittle nails may also be noticed. Since calcium is a major component of teeth, chronic calcium deficiency can lead to poor dentition and cavities. Bones can also be affected, resulting in thin bones or osteoporosis. This can lead to fractures, especially in older individuals.
When to Seek Medical Attention
Calcium deficiency that develops rapidly can be life-threatening. Seek emergency medical attention if you notice muscle spasms, twitching or cramps; tingling or numbness; fast or skipped heart beats; shortness of breath or leg swelling; or seizures. Also seek medical attention if you experience headaches, vision changes, problems with thinking or changes in mood or personality.