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Flashcards in Calcium Disorders Deck (22):
1

PTH effects

-increased bone resorption
-inc ca absorp
-decrease calcium excretion
-increase phosphate excretion
-increase 1,25 Vit D (1,25 made as needed, 25 Vit D is major storage form)

2

Ca sensor receptor on

Parathyroid cell
Parafollicular C cell
Renal tubular cell

3

Hypercalcemic Disorders

-*primary hyperparathyroidism
-Hypercalcemia of Malignancy
Granulomatous Disease
Vitamin D Intoxication
Vitamin A Intoxication
Hyperthyroidism
Thiazide Diuretics
Milk-Alkali Syndrome
Immobilization
Adrenal Insufficiency
Acute Renal Failure
*Familial Hypocalciuric Hypercalcemia

*increased PTH

4

When Ca high and phos low, suggests

PTH problem

=primary hyperparathyroidism

5

Primary hyperparathyroidism classific

adenoma: 85%
hyperplasia 15%
carcinoma: less than 1%

features:
Asx (>50%)
skeletal disease
kidney disease
GI disease
psychiatric disease
("bones, stones, groans, moans")
arthritis
muscle weakness
band keratopathy
htn
anemia

6

Dx of primary hyperparathyroidism

elevated Ca
low Phosphate
increased serum PTH

90% sporadic
10% familial (familial HPT, MEN I, MEN IIA)

7

MEN I

Pituitary tumors
pancreatic islet tumors
parathyroid hyperplasia

"3 Ps"
germline mut: menin gene

8

MEN IIA

Medullary thyroid carcinoma
pheochromocytoma (cause severe HTN)
parathyroid hyperplasia

Germline mut: Ret gene (GDNF receptor)

9

tx of primary hyperparathyroidism

XXX

surgery:
adenoma- 1 gland
hyperplasia- 3.5 glands

Calcimimetic drug (suppress PTH production): Cinacalcet
Anti-resorptive bone drug:
bisphosphonate, denosumab

10

secondary hyperparathyroidism

elevated PTH secretion as response to stim (compensatory) (low serum Ca, or low serum phosphate, or low 1,25 Vit D)

11

Hypercalcemia of malignancy

tumor types:
lung and breast cancers most common
-head/neck
kidney
bladder
panc
ovarian
multiple myeloma
lymphoma

Mediators:
PTH related peptide (PTH-RP): 90%
TGF beta
TNF
interleukin 1, interleukin 6
rankL
DKK1
1,25 OH2 Vit D

12

PTH-RP

-role in Ca transport
-first 13 aa identical to PTH, and bind to PTH receptor (osteoclastic bone resorption)
-leads to hypercalcemia of malig

13

Dx of hypercalcemia of malignancy

-increased Serum Ca, decreased serum PTH
increased PTH-RP

14

Familial hypocalciuric hypercalcemia dx

increased serum Ca (mild)
increased serum PTH
decreased urinary Ca
decreased urine ca/CrCl Ratio
(UCa x Pcr/Pca xUCr) less than 0.1

15

Causes of hypocalcemia

-assoc with elevated PTH except for hypoparathyroidism (PTH will be low)

Vitamin D Deficiency
Hypoparathyroidism*
Pseudohypoparathyroidism
Hypomagnesemia
Renal Failure
Liver Failure
Acute Pancreatitis
Hypoproteinemia**

**Need corrected serum total Ca:Add 0.8 mg/dl to total Calcium for
every 1 g/L Albumin is less than 4 g/L

16

Features of hypocalcemia

Paresthesias
Muscle Cramps
Muscle Weakness
Chvostek’s Sign
Trousseau’s Sign

17

Vit D changes Ca and Phosphate in

same direction

18

Vit D disorders

Acquired Vit D def:
poor oral intake
inadequate sunlight
Acquired 1,25 Vit def:
renal disease
hypoparathyroidism
Congenital Alpha hydroxylase def:
Vit D dep Rickets Type 1
Congenital Vit D receptor def:
Vit D dependent Rickets Type 2

19

Labs for nutritional Vit D def

low Ca
low phosphate
low 25 OH Vit D
increased serum PTH
increased serum alk phos (suggests osteomalacia)

Tx: high Vit D

20

Hypoparathyroidism lab features

low serum Ca
high serum phosphate
low serum PTH

21

Pseudohypoparathyroidism

-inability to respond to PTH
-sign: Albright's hereditary osteodystrophy (4/5th metacarpal shortening)

Labs:
low Ca
high phosphate
high PTH
short 4th/5th metacarpals

22

PTH signaling

PTH receptor
-alpha GDP subunit
-GDP disocciates, GTP assoc
-alpha GTP is active, CAMP increases, PTH action

in pseudohypoparathryroidism: low PTH action due to inability to signal (alpha GDP)