Commonest cause for hyperparathyroidism is -

Primary Hyperparathyroidism PHPT Arises from increased PTH production from abnormal parathyroid glands and results from a disturbance of normal feedback control exeed by serum calcium More common in women Solitary adenoma is the MC cause (in 80%) Parathyroid adenomas are most commonly located in Inferior parathyroid glands Increased PTH production leads to Hypercalcemia Increased GI absorption of calcium Reduced renal calcium clearance Increased production of vitamin D3 Ref: schwaz's principle of surgery 10th edition Pgno : 1560