Hypercalcemia

Question 1

Major mechanisms

Answer 1

-Increased protein binding
-Increased mobilization from bone or intestinal absorption
-Decreased urinary excretion
-Multifactorial

Question 2

Increased protein binding

Answer 2

Hyperalbuminemia usually due to hemoconcentration

Question 3

Causes of increased mobilization

Answer 3

-Increased PTH or PTHrp activity
-Hypervitaminosis D
-Localized osteolytic lesions

Question 4

Decreased urinary excretion

Answer 4

-Common in horses-> decreased renal excretion
-Dogs less common-> increased complexing with phosphates

Question 5

Neonates and young animals

Answer 5

-Presence of PTHrp in milk
-Increased bone turnover
-GH-> increases vitamin D
Higher Ca normally

Question 6

Canine hypoadrenocorticism

Answer 6

-Deficient aldosterone-> leads to hypovolemia and RAAS-> increase tubular resorption of NA and Ca
-Deficiency of corticosteroids-> decrease renal excretion and promotes intestinal absorption

Question 7

Idiopathic hypercalcemia in cats

Answer 7

Commonly reported
-PTH appropriately low
-Vitamin D, PTHrp, and P WRI
Normalizes after prednisolone of bisphosphonate

Question 8

Common causes in species

Answer 8

-Dogs-> humoral hypercalcemia of malignancy
-Cats-> idiopathic
-Horses-> chronic renal disease
-Cattle-> iatrogenic