Hypocalcemia, or low blood calcium, is caused by a loss of calcium from or insufficient entry of calcium into the blood circulation. According to LabTestsOnline.com, the most common cause of low total calcium is low blood protein levels, especially a low albumin level. According to the Merck Manuals online medical library, about 40 percent of the calcium in blood is bound to albumin. The normal adult value for calcium is 4.5 to 5.5 milliequivalent per liter, or mEq/L.
Neuropsychiatric Symptoms
Hypocalcemia can affect the brain and cause both neurologic or psychologic symptoms, such as memory loss, delirium and hallucinations. As hypocalcemia progresses, people may become depressed. With severely lowered blood calcium levels, you can become confused or disoriented. According to the Cleveland Clinic, neuropsychiatric symptoms can include all types of seizures, dementia in adults, mental retardation in children, emotional problems such as anxiety and depression, extrapyramidal symptoms -- Parkinson's disease is most common -- calcifications of basal ganglia in longstanding disease, and papilledema.
Neuromuscular Symptoms
Hypocalcemia also causes neuromuscular irritability in which nerves and muscles may spasm or twitch. Twitching may occur in the perioral, nasal and eye muscle regions. Spontaneous muscle cramps are commonly seen in hypocalcemia. Other symptoms may include cramps, stiffness or aches in your legs, arms and other muscles. This is referred to as tetany. Tetany is seen in severe hypocalcemia. An extremely low calcium level may cause tingling in the lips, tongue, fingers and toes. Low calcium levels may also lead to seizures.
Cardiac Symptoms
Hypocalcemia can also cause cardiovascular symptoms, such as electrical cycle problems in the heart, congestive heart failure and hypotension. Hypocalcemia can cause spasms of the muscles in the throat, leading to difficulty breathing, and abnormal heart rhythms that can contribute to other cardiovascular symptoms. The heart muscle may contract irregularly due to the electrolyte disturbance or low blood calcium levels.
