Which of the following is not a common site for metastatic calcification -

Ans. is 'c' i.e., ParathyroidMetastatic Calcification o When pathologic calcification takes place in normal tissues, it is called metastatic calcification. o Calcium metabolism is altered and there is hypercalcemia.So, all the conditions that cause hypercalcemia may also cause metastatic calcification.o These conditions are : - Hyperparathyroidism q Bony destructive lesions (multiple myeloma, breast Ca.) Hypervitaminosis D q Prolonged immobilization Milk alkali syndrome q Renal failure. Sarcoidosiso Sites of metastatic Calcificationo Basement membrane & tubular lamina of kidney Pulmonary veinso Alveolar wall of lung (most common site) Cornea & Conjuctiva Interstitial tissue of gastric mucosa Synovium of the joint Systemic aeries Tendons.Why these sites are involved in metastatic calcification due to hypercalcemia ?These tissues loose acid and therefore have alkaline internal environment. Alkaline pH ours precipitation of calcium salts.o Metastatic Calcification is reversible, when the metabolic disturbance are corrected.