Aetiology

Causes of primary hyperparathyroidism include:

• solitary adenoma of parathyroid chief cells - most common cause and accounts for about 85% of cases
• multiglandular parathyroid hyperplasia - responsible for 1-15% of cases with PHP
• parathyroid carcinoma - rare and occurs in less than 1% of cases
• ectopic adenomas e.g. - commonly the thymus, trachea-oesophageal groove, mediastinum, and the thyroid
• drugs
  • certain drugs such as thiazide diuretics and lithium may also alter calcium homeostasis.
  • these drugs may unmask underlying primary hyperparathyroidism

Primary hyperparathyroidism may also be associated with uncommon familial disorders e.g. - multiple endocrine neoplasia type 1 and type 2A syndromes, familial hyperparathyroidism-jaw tumour syndrome, neonatal severe hyperparathyroidism and familial isolated hyperparathyroidism (1).

Reference:

• (1) Pallan S, Rahman MO, Khan AA. Diagnosis and management of primary hyperparathyroidism. BMJ. 2012;344:e1013