According to "Nutrition and You" by Joan Salge Blake, approximately 99 percent of calcium in the body is found in the bones. The other 1 percent is divided between the cells and the bloodstream. Calcium plays crucial roles in bone formation, muscle contraction, hormone release, and proper nerve and brain function. Too much calcium in the blood, however, can disrupt these processes and cause abnormal body functioning. Calcium levels in the blood that are above normal are medically referred to as hypercalcemia.
Calcium Regulation
Two hormones, calcitonin and parathyroid hormone, regulate calcium levels in your body. When blood calcium levels are too high, the thyroid gland produces and releases calcitonin, which stops the release of calcium from the bones. This prevents calcium levels from getting too high. When calcium levels in the blood get too low, the parathyroid glands release parathyroid hormone, which triggers the release of calcium from the bones. In normal cases, once calcium levels return to normal, the parathyroid glands stop releasing parathyroid hormone.
Causes of Hypercalcemia
One of the most common causes of hypercalcemia is overactivity of the parathyroid glands, or hyperparathyroidism. When the parathyroid glands are overactive, they constantly release parathyroid hormone, even if blood calcium levels are normal or high. Not only does this raise calcium levels in the blood, but it also results in a significant loss of calcium from the bones. Hyperparathyroidism can occur as a result of calcium deficiency, vitamin D deficiency, kidney disorders and growths on the parathyroid glands, according to MayoClinic.com.
Other possible causes of hypercalcemia include hyperthyroidism, kidney failure, diuretic use, dehydration, cancerous tumors, genetic conditions, excess calcium consumption and adrenal gland failure.
Symptoms
Mild forms of hypercalcemia do not usually cause any symptoms. When calcium levels in the blood get too high, however, it can cause nausea, vomiting, loss of appetite, weight loss, increased thirst, frequent urge to urinate, abdominal pain, muscle weakness, aching joints and muscles, confusion, fatigue and constipation, according to MayoClinic.com. Severe hypercalcemia can also cause bone pain and spinal curvature, which can result in loss of height.
Treatment
Initial treatment for hypercalcemia focuses on restoring normal calcium levels in the blood. Treatment may include diuretics, administration of intravenous fluids and calcitonin supplementation. If calcium levels are very high or kidney function is low, dialysis may also be used to help filter excess calcium out of the blood. Once calcium levels return to normal, further treatment focuses on correcting the underlying cause of the hypercalcemia.
Complications
If left untreated, the continuous release of calcium from the bones can result in osteoporosis, which can lead to repeated bone fractures. Too much calcium in the blood can also lead to too much calcium in the kidneys. Excessive calcium in the kidneys may result in the formation of calcium kidney stones. Hypercalcemia can also lead to kidney failure, improper nerve function and arrhythmia, or abnormal heartbeat.
