Clinical Practice Guidelines for management of Primary Hyperparathyroidism.

Abstract

The etiology of hypercalcemia is classified into two distinct categories: PTH-dependent (iPTH> 20 pg/ml) and independent ( iPTH< 20 pg/ml) (1). PTH-dependent hypercalcemia can be caused by primary hyperparathyroidism (PHPT), tertiary hyperparathyroidism, lithium therapy, familial hypocalciuric hypercalcemia (FHH). PHPT is the most common cause of PTH-dependent hypercalcemia. FHH can be distinguished from PHPT as the former is characterised by a 24-hour urinary calcium level of less than 100 mg/day and a strong family history. Sporadic PHPT cases represent about 90-95% of all cases, resulting from  single parathyroid adenoma in 80% of cases and multiple gland involvement which is generally hyperplasic in 20% cases (2). The remaining 5-10% of cases occur within familial inherited parathyroid disorders such as MEN1, MEN2A, MEN4, FHH, neonatal severe hyperparathyroidism (NSHPT), HPT-jaw tumour (HPT-JT) [CDC 73] mutation and familial isolated PHPT (FIPH).

PHPT is the third most common endocrine disorder in the West after diabetes mellitus and thyroid disorders (3). Overall, about 1% of the adults have PHPT in the West, and this figure rises to 2% in people older than 55 years. PHPT in India for the most part continues to be a symptomatic disease with skeletal, renal, pancreatic and cardiac manifestations with high serum calcium and PTH levels (4) (5) (6).