Calcium, Phosphorus, Magnesium

Question 1

parathyroid hormone _________ serum Ca

Answer 1

Increases

-> promote renal tubular reabsorption, resorption of bone, activate Vit D

Question 2

Calcitonin is produced by ______________ and has what effect serum Ca

Answer 2

C cells of thyroid gland

Decrease serum Ca -> inhibiting PTH

Question 3

The activated form of Vit D is __________

Answer 3

Calcitriol

-> increase absorption of Ca from intestine and enhance PTH effect on bone and kidney

Question 4

An increase in plasma P will cause ___________ plasma Ca

Answer 4

Decreased

-> results in increase in PTH

Question 5

If you have a hypoalbuminemia, what occurs to calcium levels ?

Answer 5

50% of Ca is bound to albumin

-> loss of protein –> apparent hypocalcemia

Question 6

Total calcium is provided with a biochem profile, how do we correct for this?

Answer 6

Total calcium - albumin + 3.5 = corrected calcium

Question 7

An acidosis will __________ ionized Ca

Answer 7

Increase

Question 8

What are common causes of hypocalcemia?

Answer 8

Renal disease 
Ethylene glycol toxicosis 
Pancreatitis (saponification) 
Eclampsia 
Sepsis

Question 9

A C-cell thyroid tumor, can cause what biochemical abnormality?

Answer 9

Hypocalcemia

C-cell –> hypercalcitonism –> inhibit PTH –> decrease Ca

Question 10

Clinical signs associated with hypocalcemia

Answer 10

Nervousness, anorexia, stilted gait

Hyperventilation
Numbness

Generalized tetany, seizures

Question 11

What are causes of hypercalcemia?

Answer 11

Hypercalciemia of malignancy (PTHrp) 
Granulomatous inflammatory disease 
Renal disease (cat and horse) 
Idiopathic hypercalcemia of cats 
Vit D toxicosis (rodentatcides) 
Grape and raisin toxicosis 
Hypoadrenocorticism 
Primary hyperparathyroidism

Question 12

Mineralization of soft tissue can occur when the calciun x phosphorus product is >

Answer 12

60 > 70

Question 13

PTH and calcitonin ___________ phosphorus

Answer 13

Decreases

Question 14

What effect does vit D have on phosphorus

Answer 14

Increases by stimulating absorption from intestine and kidney and inhibiting PTH synthesis

Question 15

The most significant cause os hypophosphatemia is???

Answer 15

Metabolic acidosis, due to increased urinary loss

Diabetic ketoacidosis

Question 16

What are causes of hypophosphatemia ??

Answer 16

Primary hyperparathyroidism (renal loss)

Hypercalciemia of malignancy

Vit D deficiency

Respiratory alkalosis

Decreased intestinal absorption of P

Renal tubular defect

Chronic renal failure in horses

Question 17

Hyperphosphatemia can result from what conditons?

Answer 17

Vit D intoxication 
Acute acidosis (decreased used of P)
Excessive P intake 
Primary hypoparathyroidism

Question 18

Decreased GFR due to renal or pre-renal azotemia can have what effect on phosphate?

Answer 18

Hyperphosphatemia

Question 19

Where is magnesium lost through?

Answer 19

GI tract (malabsorption)

Kidney (fluid diuretics, renal disease)

Skin in horse (sweat)

Question 20

What are manifestations of hypomagensemia?

Answer 20

Secondary hypokalemia due to renal wasting of K

Impaired PTH production and real ease leading to secondary hypocalcemia

Question 21

What clinical signs are associated with hypomagnesemia?

Answer 21

Those associated with secondary electrolyte abnormalities

• hyperexcitability
• tremors, fasiculations, ataxia
• frank tetany
• cardiac arrhythmia

Question 22

When is hypermagnesemia seen?

Answer 22

Compromised renal function

Mg-contained laxatives or antacids with decreased GFR

Question 23

Clinical signs associated with hypermagnesemia?

Answer 23

Paresis, paralysis
Heart dysfunction
GI upset