Introduction
The parathyroid glands are four small lentil-sized glands near the neck’s thyroid gland. They have an important role in regulating the body’s calcium.
Some people may have an abnormal number of glands. Additionally, sometimes a parathyroid gland may be in the chest, instead of the neck.
Hyperparathyroidism occurs when one or more parathyroid glands release a high amount of parathyroid hormone (PTH). Too much PTH causes the levels of calcium in the blood to rise. A high level of PTH causes calcium deficiency by releasing too much of it from where it is stored in the bones.
Causes
The cause of hyperparathyroidism depends on the type: primary, secondary, or tertiary. Primary hyperparathyroidism is caused by a problem with one or more of the four parathyroid glands. These include a noncancerous growth on a gland, enlargement of a gland, or, in very rare cases, a cancerous tumour on the gland.
Secondary hyperparathyroidism is where the parathyroid glands compensate for a low calcium level in the blood. Another underlying condition, such as chronic kidney disease, usually causes secondary hyperthyroidism.
Tertiary hyperparathyroidism occurs when parathyroid glands remain hyperactive even after treating the underlying disease, such as people with chronic kidney disease who have received a renal transplant.
Symptoms
The most common first indication of a problem with the parathyroid glands is a high calcium level detected on blood tests performed for other reasons. This is often before any symptoms occur.
When symptoms do occur, these can be wide-ranging and sometimes subtle. They include weak bones (fractures), kidney stones, fatigue and weakness, depression and mood changes, cognitive difficulties, digestive issues, and heart and blood pressure problems.
Diagnosis
Your doctor will usually start by checking your blood pressure and performing a physical examination.
Further tests will be necessary, including blood tests, neck ultrasound and a sestamibi parathyroid scan. Additional scans are sometimes required, such as MRI and multiphase CT.