Primary hyperparathyroidism

Parathyroid hormone should be measured in any patient with hypercalcaemia; for information about management of severe acute hypercalcaemia secondary to primary hyperparathyroidism, see Hypercalcaemia. In addition to symptoms of hypercalcaemia, patients with hyperparathyroidism can experience fatigue and cognitive changes.

Primary hyperparathyroidism is most commonly caused by a single parathyroid adenoma. Definitive therapy is surgery, which cures 95% of cases and has low morbidity. See Perioperative care for parathyroid surgery.

A ‘watch and wait’ approach can be considered instead of surgery in patients who are 50 years or older, and have:

• a total serum calcium concentration corrected for albumin lower than 2.90 mmol/L
• normal kidney function
• no nephrolithiasis or nephrocalcinosis
• a bone mineral density (BMD) T-score higher than −2.5
• no symptoms.

Monitor for onset of symptoms and measure total serum calcium concentration and kidney function every 6 to 12 months, and BMD every 2 years. Using this conservative approach, around 50% of these patients will not require surgery during 10 years of follow-up. However, this can also result in decreased BMD.

Advise patients who elect not to have surgery to:

• avoid a high calcium intake (ie from diet or calcium supplements)
• limit vitamin D supplementation with colecalciferol (if required for deficiency) to 25 micrograms (1000 international units) daily
• maintain a high water intake (approximately 2.5 litres daily), unless contraindicated.

Calcimimetic drugs (eg cinacalcet) can be used for hyperparathyroidism or parathyroid cancer if surgery is not possible or is ineffective. These drugs are best used in specialist centres.

Patients younger than 40 years who present with hyperparathyroidism should be referred for genetic testing.

Patients with primary hyperparathyroidism can also have moderate hypophosphataemia; this usually resolves with management of hyperparathyroidism, and no specific treatment is required.