Hyperparathyroidism
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Basics
Description
- Parathyroid hormone (PTH) excess with symptoms owing to PTH actions, including:
- Decreases urinary Ca2+ loss
- Increases urinary PO42− loss
- Stimulates vitamin D conversion from 25(OH)-D to 1,25(OH)-D in kidney
- Liberates Ca2+ and PO42− from bone
- Hypercalcemia is the primary metabolic finding
- Hypercalciuria from hypercalcemia (despite decreased urinary loss) produces increased magnesium loss in urine
- Hypomagnesemia (due to negative feedback to prevent hypercalcemia):
- Cofactor in the production of PTH
- Essential for action of PTH in target tissues
- Genetics:
- Associated with multiple endocrine neoplasia type 1:
- Hyperparathyroidism
- Pancreatic islet disease
- Pituitary disease
- Associated with multiple endocrine neoplasia type 2:
- Hyperparathyroidism (type 2A, rare in 2B)
- Medullary carcinoma of the thyroid (type 2A and 2B, less virulent in type 2A)
- Pheochromocytoma (type 2A and 2B)
- Mucosal neuroma (type 2B)
- Associated with multiple endocrine neoplasia type 1:
Etiology
- Excess secretion of PTH owing to:
- Primary hyperparathyroidism (parathyroid single benign adenoma 85%, hyperplasia 14%, carcinoma <1%)
- Secondary hyperparathyroidism (response to vitamin D deficiency or chronic renal failure with hyperphosphatemia):
- Calcium is low or normal, but PTH levels are elevated
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Basics
Description
- Parathyroid hormone (PTH) excess with symptoms owing to PTH actions, including:
- Decreases urinary Ca2+ loss
- Increases urinary PO42− loss
- Stimulates vitamin D conversion from 25(OH)-D to 1,25(OH)-D in kidney
- Liberates Ca2+ and PO42− from bone
- Hypercalcemia is the primary metabolic finding
- Hypercalciuria from hypercalcemia (despite decreased urinary loss) produces increased magnesium loss in urine
- Hypomagnesemia (due to negative feedback to prevent hypercalcemia):
- Cofactor in the production of PTH
- Essential for action of PTH in target tissues
- Genetics:
- Associated with multiple endocrine neoplasia type 1:
- Hyperparathyroidism
- Pancreatic islet disease
- Pituitary disease
- Associated with multiple endocrine neoplasia type 2:
- Hyperparathyroidism (type 2A, rare in 2B)
- Medullary carcinoma of the thyroid (type 2A and 2B, less virulent in type 2A)
- Pheochromocytoma (type 2A and 2B)
- Mucosal neuroma (type 2B)
- Associated with multiple endocrine neoplasia type 1:
Etiology
- Excess secretion of PTH owing to:
- Primary hyperparathyroidism (parathyroid single benign adenoma 85%, hyperplasia 14%, carcinoma <1%)
- Secondary hyperparathyroidism (response to vitamin D deficiency or chronic renal failure with hyperphosphatemia):
- Calcium is low or normal, but PTH levels are elevated
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