What is PHPT?

PHPT is a common endocrine (hormonal) disease caused by the overproduction and release of parathyroid hormone (PTH).  PHPT is caused by a benign growth (adenoma) on one of the parathyroid glands in 90% of cases.

The risk of having PHPT increases with age, so as many as 1% of <60 year old persons may be affected.  However, it is not uncommon for much younger people to be affected; or, for some to have had PHPT for many years before it has become evident.

Most people have four parathyroid glands usually sited behind the thyroid gland in the neck, but some have extra glands or glands in unusual positions including the chest, inside the thymus or high in the neck.

WHAT DO THE PARATHYROIDS DO?

The parathyroid glands regulate the level of calcium in blood (like a thermostat) to keep the levels in a tightly controlled range by producing a hormone called ‘parathyroid hormone’ (PTH). PTH raises the blood calcium by promoting its release from bone (where most of the body’s calcium is stored), increasing the body’s ability to absorb calcium from food, and increasing the kidney’s ability to hold onto calcium that would otherwise be lost in urine. 

When the blood calcium is too low PTH is released to bring the calcium level back up to normal. When the calcium level is normal or gets a little too high, normal parathyroid glands will stop releasing PTH. Proper calcium balance is crucial to the normal functioning of multiple body systems and in particular the heart, nervous system, kidneys and bones.

SYMPTOMS:

Symptoms of PHPT can vary to a degree based usually on the length of time it has remained untreated. By the time many people are diagnosed due to symptoms, they will have had PHPT for some time. 

Initial symptoms begin with severe fatigue, heartburn, mood change, insomnia, aching joints (usually hip and knee) and muscle weakness.

As time progresses symptoms can worsen to cause blurred vision, headaches, kidney stones, severe bone pain, memory loss and confusion, poor coordination, depression, pancreatitis, hair loss, osteopenia or osteoporosis, unstable blood pressure; and in severe cases; strokes, heart attacks and coma.

The level of calcium does not necessarily dictate the severity of symptoms.

HOW IS PHPT DIAGNOSED?

PHPT is usually diagnosed after finding a raised level of calcium in a blood test. Typically, a repeat fasting test will be requested along with PTH and Vitamin D (to rule out secondary Hyperparathyroidism due to vitamin D deficiency). A 24 hour urine calcium (to exclude a familial condition that mimics PHPT) will confirm the diagnosis.

Once PHPT is diagnosed, bone densitometry scans of hip, spine and non-dominant forearm may be performed as high bone turnover in PHPT patients is associated with a reduction in bone mineral density specifically in the cortical bone (forearm and hip). A kidney ultrasound will see whether the disease is causing harm to the kidneys.

The next step is to locate which of the glands has developed an adenoma (sometimes there may be more than one enlarged gland. If all glands are affected it is called Hyperplasia).

Does PHPT need treatment?

Yes. The only definitive cure is to remove the diseased parathyroid gland with surgery called a parathyroidectomy. If you are asymptomatic (without symptoms) you may wish to monitor your calcium levels and bone and have surgery if things deteriorate. The chance of being cured by a single operation is highest and the risk of complications is lowest when the surgery is performed by a specialist parathyroid surgeon, which is highly advisable. You should continue to keep a reasonable level of calcium in your diet and stay hydrated until surgery.

Is there a non-surgical treatment?

A surgical parathyroidectomy is the only cure for PHPT.  A drug is available called Cinacalcet to reduce calcium levels back to normal range but this does not help kidney and bone disease. Cinacalcet is licenced only for the treatment of parathyroid cancer, as a holding measure prior to surgery or in the small number of patients that are considered not fit enough for surgery or where the risks of surgery are too high.