Calcium is an important mineral in the growth and development of bone. It is also important to maintain the function of nerves, muscles, and the heart. The kidneys are a pair of bean-shaped organs that help regulate the body's fluid and electrolyte balance. When the kidneys are damaged, serious electrolyte dysfunctions can occur, including low calcium.
Kidneys and Calcium
The majority of calcium in the body is stored within bones. According to the Merck Manuals, when the level of calcium falls, several hormones, including the parathyroid hormone, stimulate the breakdown of bone to increase calcium levels. The parathyroid glands, a set of four glands embedded within the thyroid in the neck, also stimulate the kidneys to retain more calcium if the levels are too low. When a person suffers from kidney disease, the parathyroid glands are unable to stimulate the retention of calcium, resulting in more calcium lost in the urine.
Kidney Diseases that Affect Calcium
Renal, or kidney, failure is a common cause of low calcium, or hypocalcemia. When the kidneys fail, they are unable to process and filter the blood from waste products, decreasing its ability to reabsorb calcium and leading to loss of calcium in the urine. Kidney failure can occur acutely, or suddenly, or over a long period of time, a condition known as chronic renal failure. According to the National Library of Medicine, causes of acute renal failure include autoimmune kidney disease, in which the body attacks the kidneys as if they were foreign tissue, dehydration, burns, bleeding and infection.
Symptoms
The symptoms of low calcium include muscle irritability, aches, spasms, tingling of the lips, fingers and toes, and tetany, an abnormal painful stiffening and spasm of the hands and feet. According to the Cleveland Clinic, other symptoms include seizures, dementia, depression and tremors resembling Parkinson's disease. Low calcium can affect the heart, leading to abnormal heart rhythms, low blood pressure and heart failure.
Treatment
The treatment of low calcium includes supplementation with either oral or intravenous calcium solutions. If given intravenously, it must be given slowly to avoid precipitating an abnormal heart rhythm. Vitamin D supplementation may also be necessary, as this vitamin stimulates the absorption of calcium from the gut. If the cause of low calcium is renal disease, this must be addressed. In patients with chronic renal disease, dialysis may be necessary to correct the calcium level.
