PARATHYROID AND CALCIUM ABNORMALITIES

HYPERCALCEMIA AND HYPERPARATHYROIDISM

Parathyroid hormone

• Very short serum t-1/2
• Effects: inhibits osteoblasts; stimulates GI epith. and renal tubules to reabs. Ca; inhibits renal tubular reabsorp. of PO4 ("phosphate diuresis"); ?effects on vit. D metabolism?

Drug f/x on Ca homeostasis:

• Thiazides increase Ca reabssorption
• Loop diuretics increase calciuresis

Consider Celiac sprue as a possible cause of hypocalcemia (through vit. D deficiency)

See also section on Dietary Calcium Intake and Calcium Supplements