Hyperparathyroidism

What the parathyroid glands do

The four parathyroid glands, each about the size of a grain of rice, sit behind the thyroid. They release PTH when blood calcium falls. PTH raises calcium by:

• releasing calcium from bones
• reducing calcium loss in the urine
• activating vitamin D, which increases calcium absorption from food

In hyperparathyroidism, this system is overactive.

Types of hyperparathyroidism

Primary hyperparathyroidism is common, especially in women after menopause. Most cases are found by chance on routine blood tests.

Risk factors for primary hyperparathyroidism

• female sex and age over 50
• previous radiation to the neck
• lithium treatment
• inherited syndromes such as multiple endocrine neoplasia (MEN1 and MEN2A), especially in younger people or when several family members are affected

Symptoms

Many people have no obvious symptoms. When present, they are summed up by the old phrase "stones, bones, abdominal groans and psychic moans":

• Stones: kidney stones, excessive thirst and urination
• Bones: bone thinning (osteoporosis), fractures, bone and joint aches
• Groans: constipation, nausea, loss of appetite, peptic ulcers, pancreatitis
• Moans: tiredness, weakness, low mood, anxiety, poor memory and concentration, sleep problems

Very high calcium can cause confusion, dehydration, heart rhythm problems and coma.

Diagnosis

1. Blood calcium (adjusted for albumin, or ionized calcium), repeated to confirm
2. PTH level: high or inappropriately normal with high calcium confirms primary hyperparathyroidism
3. Vitamin D, phosphate, kidney function (creatinine and eGFR)
4. 24-hour urine calcium to assess kidney stone risk and rule out familial hypocalciuric hypercalcemia, a harmless inherited condition that mimics it
5. Bone density (DEXA) scan, including the forearm, where PTH effects show most
6. Kidney imaging for silent stones
7. Localization scans before surgery: neck ultrasound, sestamibi scan or 4D-CT to find the overactive gland

Treatment

Surgery (parathyroidectomy)

Removing the overactive gland or glands is the only cure for primary hyperparathyroidism, with success rates above 95 percent in experienced hands. Surgery is recommended for anyone with symptoms and is advised for people without symptoms who have any of:

• calcium more than 1 mg/dL (0.25 mmol/L) above the upper limit of normal
• osteoporosis or a vertebral fracture
• reduced kidney function, kidney stones or high urine calcium
• age under 50

Many experts now offer surgery to most people who are fit enough, because it can improve bone density and possibly symptoms such as fatigue. A minimally invasive approach through a small incision is often possible, with same-day discharge. Risks include temporary low calcium and, rarely, injury to the nerve that controls the voice.

Monitoring

People who do not have surgery are monitored with yearly calcium and kidney tests and bone density scans every 1 to 2 years. Advice includes:

• drinking plenty of fluids
• a normal (not low) calcium intake from food
• keeping vitamin D in the normal range
• avoiding thiazide diuretics and lithium where possible
• staying physically active

Medicines

• Cinacalcet: lowers PTH and calcium, used when surgery is not possible
• Bisphosphonates or denosumab: protect bones

Secondary hyperparathyroidism

Treatment focuses on the cause: vitamin D replacement, adequate calcium, and in chronic kidney disease, phosphate control, active vitamin D and calcimimetics. Surgery is sometimes needed in advanced kidney disease.

Outlook

After successful surgery, calcium returns to normal, bone density improves and the risk of new kidney stones falls. Long-term follow-up checks for recurrence, which is more common in hereditary forms.

Frequently asked questions

What are the symptoms of hyperparathyroidism?

Many people have no symptoms. Others have kidney stones, bone thinning or fractures, tiredness, thirst, frequent urination, constipation, nausea, aches, low mood and poor concentration. Very high calcium can cause confusion and heart rhythm problems.

What causes primary hyperparathyroidism?

Most cases are caused by a single benign tumor called a parathyroid adenoma. Less commonly, all four glands are enlarged, often in inherited syndromes. Parathyroid cancer is rare. Previous neck radiation and lithium raise the risk.

What is the difference between primary and secondary hyperparathyroidism?

In primary hyperparathyroidism, the glands make too much hormone on their own, raising calcium. In secondary hyperparathyroidism, the glands overwork in response to low calcium or vitamin D, often due to kidney disease, and calcium is normal or low.

Is parathyroid surgery worth it if I have no symptoms?

Guidelines recommend surgery for people without symptoms if calcium is markedly high, bones are thin, kidney function is affected, kidney stones or high urine calcium are present, or age is under 50. Many people also feel better after surgery. Discuss the risks and benefits with an endocrine surgeon.

Can hyperparathyroidism be cured?

Primary hyperparathyroidism is cured in more than 95 percent of people by removing the overactive gland or glands. Secondary hyperparathyroidism improves when the underlying cause, such as vitamin D deficiency, is treated.