Disorders of calcium metabolism Flashcards
- Contrast the mechanisms underlying the main causes of hypercalcemia, including primary hyperparathyroidism and hypercalcemia of malignancy.
primary hyperparathyroidism -adenoma, high PTH -hyperplasia, high PTH Familial Hypocalciuric Hypercalcemia -low urine calcium/cr clearance ratio -moderate increase in PTH -moderate increase in serum calcium Hypercalcemia of malignancy -high PTHrP, low PTH
all other hypercalcemic disorders have decreased PTH
(Hypercalcemia of Malignancy, Granulomatous Disease(very high level of activated vit D), Vitamin D Intoxication, Vitamin A Intoxication, Hyperthyroidism, Thiazide Diuretics, Milk-Alkali Syndrome, Immobilization
Adrenal Insufficiency, Acute Renal Failure
- Describe the effects of prolonged untreated hyperparathyroidism on the bones and kidneys.
asymptomatic >50%
BONES -brown tumor (benign osteoclastoma) -chondrocalcinosis -band keraopathy STONES -kidney stones from excess spillage of calcium GROANS MOANS
- Compare and contrast the pathophysiology and treatment of primary hyperparathyroidism when caused by adenoma versus hyperplasia.
adenoma is usually an issue with 1 out of 4 lobes, u can remove it and its fine
hyperplasia, we get rid of 3.5 lobes
- Describe the calcium receptor and the abnormalities caused by its dysfunction: resistance and hypersensitivity.
resistance= FHH, too much PTH hypersensitivity= too little PTH
- List five causes of hypocalcemia and the mechanisms of each of these disorders.
Increased PTH
- Vit D deficiency
- psudeohyperparathyroidim
- hypomagnesia
- renal failure
- liver failure
- acute pancreatitis
- Hypoproteinuria (make sure to check corrected serum calcium (add 0.8 mg/dL to total calcium for every 1 g/L albumin is
- Describe the clinical and laboratory features of hypoparathyroidism.
parathesias muscle cramps proximal muscle weakness chovsteks sign Trousseaus sign
serum calcium down
serum phosphate up
PTH down
If its a vit D issue
calcium and phosphate are both down, go in same direction
what does calcitonin do?
decrese osteoclastic activity
MEN I
3 P’s, AD, germline Menin mutation
Pituitary tumors
Pancreatic Islet Tumors
Parathyroid Hyperplasia
MEN 2A
RET gene
Medullary Thyroid Carcinoma
Pheochromocytoma
Parathyroid Hyperplasia
Hypercalcemia of malignancy
related to many types of cancer 90% caused by PTH related peptide Dx- increased serum calcium decreased PTH increased serum PTH-RP
Psuedohyperparathyroidism
inability to repsond to PTH
- albrights hereditary osteodystrophy (short 4th and 5th metacarpal)
- serum ca down, serum phos up, PTH up
FHH
G protein coupled receptor found in parathyroid c cell, parfollicular c cell (calcitonin cell), and renal tubular cell
FHH (familial Hypocaliuric Hypercalcemia)
- calcium sensor receptor doesn’t work,
- increased PTH
- decreased calcium excretion
- -> urine ca/cr ratio
