Overview Parathyroid glands Hyperparathyroidism is an excess of parathyroid hormone in the bloodstream due to overactivity of one or more of the body's four parathyroid glands. These glands are about the size of a grain of rice and are located in your neck. The parathyroid glands produce parathyroid hormone, which helps maintain an appropriate balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning. Two types of hyperparathyroidism exist. In primary hyperparathyroidism, an enlargement of one or more of the parathyroid glands causes overproduction of the hormone, resulting in high levels of calcium in the blood (hypercalcemia), which can cause a variety of health problems. Surgery is the most common treatment for primary hyperparathyroidism. Secondary hyperparathyroidism occurs as a result of another disease that initially causes low levels of calcium in the body and over time, increased parathyroid hormone levels occur. The range of signs and symptoms include: Fragile bones that easily fracture (osteoporosis) Kidney stones Excessive urination Abdominal pain Tiring easily or weakness Depression or forgetfulness Bone and joint pain Frequent complaints of illness with no apparent cause Nausea. they're the result of damage or dysfunction in other organs or tissues due to high calcium levels circulating in the blood and urine or too little calcium in bones.Symptoms Hyperparathyroidism is often diagnosed before signs or symptoms of the disorder are apparent. When symptoms do occur. It's important to get a prompt. Request an Appointment at Mayo Clinic Causes . accurate diagnosis and appropriate treatment. Symptoms may be so mild and nonspecific that they don't seem at all related to parathyroid function. vomiting or loss of appetite When to see a doctor See your doctor if you have any signs or symptoms of hyperparathyroidism. or they may be severe. including some with serious complications. These symptoms could be caused by any number of disorders. When blood-calcium levels are too high. Normally. the parathyroid glands produce less PTH. When calcium levels in your blood fall too low. Parathyroid glands Hyperparathyroidism is caused by factors that increase the production of parathyroid hormone. The parathyroid glands maintain proper levels of both calcium and phosphorus in your body by turning the secretion of parathyroid hormone (PTH) off or on. But sometimes one or more of these glands produce too much hormone. your parathyroid glands secrete enough PTH to restore the balance. PTH raises calcium levels by releasing calcium from your bones and increasing the amount of calcium absorbed from your small intestine. much like a thermostat controls a heating system to maintain a constant air temperature. But calcium has other functions. this balancing act works well. The mineral calcium is best known for its role in keeping your teeth and bones healthy. and . It aids in the transmission of signals in nerve cells. leading to abnormally high levels of calcium (hypercalcemia) and low levels of phosphorus in your blood. Vitamin D also is involved in regulating the amount of calcium in your blood. If you don't get enough vitamin D. Your body produces vitamin D when your skin is exposed to sunlight. Hyperparathyroidism may occur because of a problem with the parathyroid glands themselves (primary hyperparathyroidism) or because of another disease that affects the glands' function (secondary hyperparathyroidism). works in conjunction with calcium in these areas. Secondary hyperparathyroidism Secondary hyperparathyroidism is the result of another condition that lowers calcium levels. and you consume some vitamin D in food. Vitamin D helps maintain appropriate levels of calcium in the blood. Your body may not get enough calcium from your diet. and it helps your digestive system absorb calcium from your food. The disorder can generally be divided into two types based on the cause. Severe vitamin D deficiency. Factors that may contribute to secondary hyperparathyroidism include: Severe calcium deficiency. but some people inherit a gene that causes the disorder. another mineral. your parathyroid glands overwork to compensate for the loss of calcium. Primary hyperparathyroidism usually occurs randomly. Therefore. Phosphorus. Primary hyperparathyroidism Primary hyperparathyroidism occurs because of some problem with one or more of the four parathyroid glands: A noncancerous growth (adenoma) on a gland is the most common cause.it's involved in muscle contraction. Enlargement (hyperplasia) of two or more parathyroid glands accounts for most other cases. then calcium levels may drop. often because your digestive system doesn't absorb the calcium from it. A cancerous (malignant) tumor is a rare cause of primary hyperparathyroidism. . Chronic kidney failure is the most common cause of secondary hyperparathyroidism. brittle bones that fracture easily (osteoporosis). Common complications include: Osteoporosis. untreated hyperparathyroidism in pregnant women may cause dangerously low levels of calcium in newborns. The loss of calcium often results in weak. usable vitamin D may decline and calcium levels drop. . which can cause small. Chronic kidney failure. The excess of calcium in your blood may lead to excess calcium in your urine. Severe. such as high blood pressure (hypertension) and certain types of heart disease. Your kidneys convert vitamin D into a form that your body can use. a drug most often used to treat bipolar disorder Complications Complications of hyperparathyroidism are primarily related to the long-term effect of too little calcium in your bones and too much calcium circulating in your bloodstream. severe calcium or vitamin D deficiency Have a rare. If your kidneys function poorly. type 1. Although the exact cause-and-effect link is unclear. Risk factors You may be at an increased risk of primary hyperparathyroidism if you: Are a woman who has gone through menopause Have had prolonged. A kidney stone usually causes significant pain as it passes through the urinary tract. such as multiple endocrine neoplasia. inherited disorder. Neonatal hypoparathyroidism. Cardiovascular disease. high calcium levels are associated with cardiovascular conditions. Kidney stones. hard deposits of calcium and other substances to form in your kidneys. which usually affects multiple glands Have had radiation treatment for cancer that has exposed your neck to radiation Have taken lithium.