Calcium, Phos, Mg

Question 1

Common causes of hypercalcemia

Answer 1

hypercalcemia of malignancy
granulomatous inflammatory conditions 
renal dz (common in horses)
idiopathic hypercalcemia of cats 
vit d toxicity/grape + raisin toxicity 
hypoadrenocorticism/ 1 hyper-PTH

Question 2

Common causes of hypocalcemia

Answer 2

renal dz
eg toxicity
pancreatitis
eclampsia

Question 3

Not so common causes of hypocalcemia

Answer 3

hypo-pth
nutritional aka 2ndary hypo-PTH
malabsorption 
decrease Mg
increase Phos
massive tissue degeneration

Question 4

Ca:P ratio

Answer 4

Ca Phos cross product, if >70 will see mineralization of soft tissues
Most affected: blood vessels, kidneys, lungs

Question 5

Causes of hyperphophotemia

Answer 5

decreased GFR (pre-renal or renal azotemia) 
vit d toxicity/1 hypo-PTH/nutritional- excess vitD 
Acute acidosis (due to decrease use of phos)

Question 6

Causes of hypophosphotemia

Answer 6

metabolic acidosis (urinary losses) most common

Other causes: 1 hyper-pth, hypercalcemia of malignancy, vitD deficiency/GI absorption, respiratory alkalosis, renal tubular defects (fanconi syndrome), chronic renal failure (horses)

Question 7

What is apparent hypocalcemia?

Answer 7

Ca bound to alb is decreased (alb also decreased)

Question 8

How do you calculate corrected ca?

Answer 8

total ca - alb + 3.5

Question 9

Does acidosis increase or decrease ionized Ca? What about alkalosis?

Answer 9

acidosis= increase ionized Ca
alkalosis = decrease ionized Ca

Question 10

Clinical signs of hypocalcemia

Answer 10

nervousness, anorexia, stilted gait
hyperventilation, numbness
generalized tetany, seizures

Question 11

Clinical signs of hypercalcemia

Answer 11

pupd
lethargy, weakness, constipation
mineralization of soft tissue (ca x phos = >60)

Question 12

Common causes of Hypomagnesemia

Answer 12

loss through GI, kidney and skin in horses (sweat) 
dietary deficiency in ruminants (grass tetany) 
Mg absorption (milk tetany- calves fed low mg diet)

Question 13

Other/Additional disorders associated with hypomagnesemia

Answer 13

diabetes mellitus (diuresis)
hypercalcemia (inhibits Mg reabsorption)
hyperaldosteronism (diuresis)
3rd space

Question 14

Manifestations of hypomagnesemia

Answer 14

2ndary hypokalemia due to renal wasting of K

Impaired PTH production and release leading to 2ndary hypocalcemia

Question 15

Causes of hypermagnesemia

Answer 15

comprimised renal function (similar to K)

mg-containing meds + decreased GFR