Disorders of calcium metabolism Flashcards

1
Q
  1. Contrast the mechanisms underlying the main causes of hypercalcemia, including primary hyperparathyroidism and hypercalcemia of malignancy.
A
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

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2
Q
  1. Describe the effects of prolonged untreated hyperparathyroidism on the bones and kidneys.
A

asymptomatic >50%

BONES
-brown tumor (benign osteoclastoma)
-chondrocalcinosis 
-band keraopathy
STONES
-kidney stones from excess spillage of calcium
GROANS
MOANS
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3
Q
  1. Compare and contrast the pathophysiology and treatment of primary hyperparathyroidism when caused by adenoma versus hyperplasia.
A

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

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4
Q
  1. Describe the calcium receptor and the abnormalities caused by its dysfunction: resistance and hypersensitivity.
A
resistance= FHH, too much PTH
hypersensitivity= too little PTH
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5
Q
  1. List five causes of hypocalcemia and the mechanisms of each of these disorders.
A

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
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6
Q
  1. Describe the clinical and laboratory features of hypoparathyroidism.
A
parathesias
muscle cramps
proximal muscle weakness
chovsteks sign
Trousseaus sign

serum calcium down
serum phosphate up
PTH down

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7
Q

If its a vit D issue

A

calcium and phosphate are both down, go in same direction

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8
Q

what does calcitonin do?

A

decrese osteoclastic activity

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9
Q

MEN I

A

3 P’s, AD, germline Menin mutation

Pituitary tumors
Pancreatic Islet Tumors
Parathyroid Hyperplasia

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10
Q

MEN 2A

A

RET gene

Medullary Thyroid Carcinoma
Pheochromocytoma
Parathyroid Hyperplasia

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11
Q

Hypercalcemia of malignancy

A
related to many types of cancer
90% caused by PTH related peptide
Dx- increased serum calcium
decreased PTH
increased serum PTH-RP
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12
Q

Psuedohyperparathyroidism

A

inability to repsond to PTH

  • albrights hereditary osteodystrophy (short 4th and 5th metacarpal)
  • serum ca down, serum phos up, PTH up
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13
Q

FHH

A

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
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