Effect of hyperparathyroidism (osteopenia, osteoporosis, kidney stones)

The parathyroids are small glands located in the neck near the thyroid gland.  There are usually 4 parathyroid glands, but occasionally a person may have fewer or more glands. The parathyroid glands produce parathyroid hormone, which regulates the levels of calcium and phosphorus in the body. Calcium and phosphorus are important for the function of every cell in the body. Therefore, an imbalance in these levels from a poorly functioning gland can cause a multitude of problems. Hyperparathyroidism is a condition where one or more of the parathyroid glands becomes hyperactive and secretes too much parathyroid hormone. Parathyroid hormone then causes an elevated calcium level in the blood.

Elevated calcium level in blood leads to dysfunction of several organs. The kidneys are affected because the kidneys are the organs that filter the blood, removing excess or harmful substances. When calcium levels in blood are high, the kidney must try to remove the extra calcium in the blood. This calcium can build up inside of the kidneys and form a kidney stone. Kidney stones are not only very painful. They can also damage and scar the kidney, particularly if they are large or numerous.

Parathyroid hormone causes and elevated calcium level in blood, in part, by removing calcium from the bones. Calcium is one of the minerals in bones that give the bone its strength. When calcium is removed due to hyperparathyroidism, the bones become weaker and prone to fracture. Osteopenia and osteoporosis are the terms used to describe bones weakened by decreased calcium content. While both are serious conditions, osteoporosis is a more severe weakening than osteopenia. In addition to fractures, weak bones may also be painful. Bone pain in hyperparathyroidism is often in the arm and leg bones, but can affect any bone in the body.

Muscles, including the muscle of the heart, rely on calcium to function properly. Elevated calcium level in blood can cause symptoms of muscle weakness and can permanently damage the heart. When heart muscle is weak and does not function properly, the heart compensates but increasing the amount of muscle so that the heart can pump with more force. Increased muscle, however, decreases the space inside the heart for the blood to pass through. This imbalance of heart muscle and size can lead to serious problems.  Left ventricular hypertrophy symptoms include shortness of breath and decreased ability to exercise (such as not being able to walk as far or not being able to complete household chores).   Elevated calcium level in blood also can affect the heart by causing irregularities in the heart beat (called arrhythmias). Arrhythmias are life threatening and should be evaluated by a doctor immediately.