Parathyroid and Hyperparathyroidism
The parathyroids are four tiny glands located behind the thyroid gland in the neck. They are the smallest organs in the body, and the only organs with a quadruple configuration. Parathyroids secrete a hormone known as parathormone or parathyroid hormone (PTH). This hormone controls calcium metabolism in the body, affecting calcium levels in the blood, bones and urine. Normal blood calcium levels are important for maintaining proper function of the muscles, nerves and other cells throughout the body.
Hyperparathyroidism occurs when abnormally high amounts of PTH are produced by one or more of the parathyroid glands. A potentially serious problem, excessive levels of PTH can elevate blood calcium by leeching calcium out of the bones. Abnormal blood calcium levels are often discovered during routine testing when the patient has no obvious symptoms. The condition can lead to bone thinning (osteoporosis), bone pain and a higher risk for fractures. In addition, excess blood calcium can cause abdominal pain, weakness, fatigue, psychic distress and other troublesome symptoms. As the excess calcium is cleared in the urine, kidney stones may result.
Causes of Hyperparathyroidism
Hyperparathyroidism is usually the result of benign tumors enlarging one or more of the parathyroid glands.
- Most commonly one gland is affected, known as a parathyroid adenoma.
- In less than 5 percent of cases, two parathyroid glands are affected by tumors, called a double adenoma.
- Very rarely, hyperparathyroidism can be due to the enlargement of a fifth gland, sometimes discovered in a very unusual location such as high in the neck or low in the chest.
- Four-gland hyperplasia, a condition in which all four parathyroids are enlarged, also causes hyperparathyroidism. Most patients with four-gland hyperplasia have either kidney disease, a family history of hyperparathyroidism or a condition known as multiple endocrine neoplasia — tumors in many glands.
In less than 1 percent of patients with hyperparathyroidism, the condition is caused by cancer of a parathyroid gland.
Symptoms of Hyperparathyroidism
One way to group symptoms is through easy-to-remember rhymes: stones, bones, abdominal groans, moans and psychic overtones.
- Stones — Kidneys compensate for high calcium blood levels by passing calcium in the urine, a process that can form kidney stones.
- Bones — Because calcium is removed from the bones, patients can experience increased bone pain and risk of fractures. Testing with DEXA can determine bone density and the presence of osteoporosis, which can be effectively treated.
- Abdominal groans — Though rare, hyperparathyroidism can cause peptic ulcers or inflammation of the pancreas.
- Moans — Muscle weakness and fatigue are common symptoms.
- Psychic overtones — Mental dysfunction and other forms of psychic distress can accompany the disorder.
Diagnosis and Treatment of Hyperparathyroidism
Patients undergo parathyroid localization testing to pinpoint the position of the enlarged parathyroid(s). Diagnostic tools include a painless neck ultrasound and isotope scan performed in the nuclear medicine unit at Virginia Mason.
Treatment for hyperparathyroidism is removal of the enlarged parathyroid(s). This surgery restores blood calcium and PTH to normal levels, and in most cases, cures the disorder.