Hyperparathyroidism is an excess of parathyroid hormone in the bloodstream. This occurs due to overactive parathyroid glands (one or more). The parathyroid glands are located in the neck.

The parathyroid hormone helps maintain a balance of calcium in the bloodstream and in tissues whose function depends on calcium.

There are two types of hyperparathyroidism, primary and secondary hyperparathyroidism. In primary hyperparathyroidism there is an enlargement of one or more of the parathyroid glands that causes overproduction of the hormone leading to high levels of calcium in the blood (hypercalcemia). The most common treatment for primary hyperthyroidism is surgery.

Secondary hyperparathyroidism is the result of another disease that causes low calcium levels in the body over time.



Symptoms of hyperparathyroidism include:


  • Fragile bones that fracture easily (osteoporosis)
  • Kidney stones
  • Excessive urination
  • Abdominal pain
  • Weakness or fatigue
  • Depression or forgetfulness
  • Bone and joint pain
  • Nausea, vomiting or loss of appetite
  • Frequent complaints of illness



Hyperparathyroidism is caused by factors that increase the production of parathyroid hormone.


Primary hyperparathyroidism


  • A noncancerous growth (adenoma) on a parathyroid gland
  • Enlargement (hyperplasia) of two or more parathyroid glands
  • A cancerous (malignant) tumor (rare)


Primary hyperparathyroidism usually occurs at random but some people inherit a gene that may cause the disorder.


Secondary hyperparathyroidism


  • Severe calcium deficiency most often because the digestive system does not absorb the calcium.
  • Severe vitamin D deficiency can cause for calcium levels to drop
  • Chronic kidney failure disables the kidney from converting vitamin D and thus calcium levels drop.


Risk factors

Risk factors for primary hyperparathyroidism include:


  • Being a woman who has gone through menopause
  • Prolonged, severe calcium or vitamin D deficiency
  • Rare, inherited disorder such as multiple endocrine neoplasia, type 1
  • Radiation treatment for cancer, especially radiation exposure of the neck
  • Certain medications such as lithium



Complications of hyperparathyroidism are mainly associated with long-term effect of calcium deficiency in the bones and too much calcium in the bloodstream.


Complications may include:


  • Osteoporosis: Calcium deficiency can cause weak, brittle bones that fracture easily.
  • Kidney stones: Excess calcium in the blood leads to excess calcium in the urine, which can cause hard deposits of calcium to form in the kidneys.
  • Cardiovascular disease: High calcium levels are associated with high blood pressure (hypertension) and certain types of heart disease.
  • Neonatal hypoparathyroidism: Severe, untreated hyperparathyroidism in pregnant women can cause low levels of calcium in newborns.