<s>[INST] context: Hyperparathyrodism is defined as elevated serum PTH due to increased secretion. It is of two types. a) Primary & b) Secondary with a rare third type - c) Teiary Primary hyperparathyroidism Primary hyperparathyroidism is due to intrinsic abnormality of one or more parathyroid glands: Single Adenoma - 83% Multiple Adenomas - 6% Hyperplasia - 1% Carcinoma - 1% Adenomas and hyperplasia of the parathyroid usually occur sporadically, but in few cases, they are pa of familial syndromes Familial syndromes associated with Primary Hyperparathyroidism MEN type 1-Wermer's syndrome MEN type 2a - Sipple syndrome Familial hypocalciuric hypercalcemia Secondary Hyperparathyroidism Sec. hyperparathyroidism is increased secretion of PTH by the parathyroids in response to a lowered serum ionized calcium leve Causes Chronic renal failure (most common cause) Malabsorption syndrome Vitamin D deficiency Medullary carcinoma of thyroid Teiary Hyperparathyroidism Teiary hyperparathyroidism follows long standing secondary HPT when the chronically stimulated parathyriod glands act independently of the serum calcium concentration. Autonomous hypersecretion of PTH may persist despite correction of the underlying condition. [/INST] question: Primary hyperparathyroidism is caused by -a) Parathyroid hyperplasiab) Adenosisc) MEN 1d) Thyrotoxicosise) CRF | options: A: ab B: bc C: abc D: bcd | answer: C </s>