The blood consists of cells and a fluid portion containing proteins and electrically charged minerals known as electrolytes. One such electrolyte is calcium. As with the other electrolytes, the levels of calcium in the blood are restricted to a narrow range. Too much or too little calcium in the blood leads to problems in the body. Causes of hypocalcemia, or low calcium levels, include low levels of parathyroid hormone, vitamin D or magnesium. It can also be caused by pancreatitis, high phosphate levels, blood infections, cancer and some chemotherapy drugs. Low blood calcium results in a number of problems.
Muscle Complications
One of the main complications of hypocalcemia is neuromuscular irritability, which means problems in the nerves and muscles. Muscle cramps, stiffness and spasms can progress to tetany. Tetany is a tightening of the muscles without relaxation, making the muscle stiff and the affected area immobile. This tendency toward muscle spasm can be tested for clinically on physical exam by looking for two signs. Trousseau's sign is spasm of the hand and forearm when a blood pressure cuff is inflated over the arm. Chvostek's sign is a contraction of the facial muscles when the skin in front of the ear is tapped by a finger.
Peripheral Nerve Complications
As part of the neuromuscular irritability, the peripheral nerves, meaning those in the body as opposed to the brain and spinal cord, may begin to feel numb and tingly. This happens particularly around the mouth, fingers and toes if the calcium level is extremely low. This may or may not accompany muscular problems. In addition, the neuromuscular dysfunction can lead to laryngospasm. In this condition the muscles of the throat spasm, causing difficultly with breathing resulting in the skin turning blue.
Brain Complications
In addition to affecting the nerves of the body, low calcium levels affect nerves in the brain. Complications in the central nervous system from hypocalcemia include seizures, emotional problems such as anxiety and depression, personality changes, dementia in adults and developmental delay in children. It can also cause parkinsonism, consisting of shaking hands and fingers, difficulty moving and a mask-like face. It can also cause psychosis, confusion and disorientation.
Heart Complications
Since low calcium levels have a profound effect on nerves and muscles, the heart may also be affected. It is a muscular pump that contracts based on electrical signals modulated by nerves. Low calcium levels affect the ECG, which measures the electrical activity of the heart. Hypocalcemia can also cause congestive heart failure, which occurs when the heart does not pump adequately and fluid builds up in the body. In addition, low calcium levels can cause low blood pressure.
