Calcium disorders

Question 1

what should you check if we see a low total calcium

Answer 1

check for hypoalbuminaemia

Question 2

If we see high total calcium what should we check

Answer 2

phosphate levels

Question 3

What will happen if both calcium and phosphorous high in blood

Answer 3

will complex/precipitate
in tissues= mineralisation
this can affect the structure of some organs- and therefore their function

Question 4

List 6 mechanisms of hypercalcaemia

Answer 4

Increased PTH activity
Activity of PTH-like substances- neoplasia
Increased Vitamin D activity
Osteolysis
Other/unclear mechanism:
- Hypoadrenocorticism
- Feline idiopathic hypercalcaemia
- Raisin toxicity

Question 5

List the 6 most common causes of total hypercalcaemia in dogs

Answer 5

1. Malignancy
2. Hypoadrenocorticism
3. Primary hyperparathyroidism
4. Chronic renal failure
5. Vitamin D toxicosis
6. Granulomatous diseases

Question 6

List the 4 most common causes of total hypercalcaemia in cats

Answer 6

1. Idiopathic hypercalcaemia
2. Renal failure (total mainly, occ iCa)
3. Malignancy (lymphoma and squamous cell carcinoma)
4. Primary hyperparathyroidism

Question 7

what age does idiopathic hypercalcaemia affect

Answer 7

youn to middle aged cats

Question 8

What are the signs of hypercalcaemia

Answer 8

PU/PD
vomiting
anorexia
muscle weakness
dehydration

Question 9

what age does primary hyperparathyroidism generally affect

Answer 9

middle aged to geriatric disease

Question 10

If we see hign serum ionised Ca and high serum parathyroid hormone what do we suspect

Answer 10

primary hyperparathyroidism

Question 11

If we see hig hserum ionised Ca and low serum parathyroid hormone what do we suspect

Answer 11

PTH independent hypercalcaemia (e.e. malignancy, vitamin D toxicity

Question 12

What is measuring 25 hydroxy vitamin D good indicator of

Answer 12

Excellent indicator of dietary sufficiency and excess
BUT
Will not detect vit D analogues

Question 13

Describe the generic treatment for hypercalcaemia

Answer 13

Determine urgency by Ca x P
Fluids/diuresis- NaCl and frusomide
Glucocorticoids
Bisphosphanates

Question 14

Describe the effects of vitamin D on calcium in the body

Answer 14

causes the liver to produce calcidiol, which is turned into calcitriol in the kidneys-which increases Ca absorption from tubules

Question 15

Describe the effects of PTH on calcium levels

Answer 15

PTH increases calcium turnover in the bone and stimulates the kidneys to release calcitriol, as well as stimulating the kidneys to decrease calcium clearance

Question 16

what is the function of calcitriol

Answer 16

causes an increase in calcium uptake in gut

Question 17

If you get hypercalcaemia, what do you need to check

Answer 17

if your patient is abnormal or is your sample abnormal

Question 18

why is total calcium not as reliable as ionised calcium levels

Answer 18

total calcium can be affected by other things

Question 19

How does low albumin levels affect toatl calcium values in blood

Answer 19

it will cause a low calcium, as there will be less bound calcium

Question 20

Describe how phosphorous affects total calcium values

Answer 20

higher phosphate will mean more calcium binding- this creates an increased complexed fraction of calcium
the body responds by increasing PTH due to low ionized calcium- this creates high calcium level

Question 21

Describe how renal secondary hyperparathyroidism occurs

Answer 21

FGF-23 lowers and this causes decreased calcitriol and reduced calcium absorption, this causes an increased PTH

Question 22

List 7 causes of vitamin D excess

Answer 22

over-supplementation
incorrect dietary formulation
rodenticide
vitamin D analogues
plants
granulomatous disease
immunological

Question 23

Describe how hypoadrenocorticism cause hypercalcaemia

Answer 23

The exact mechanism is unknown -but it is suspected that dehydration and an increased protein concentration, combined with decreased renal excretion

Question 24

What parasite can cause hypercalcaemia in dogs

Answer 24

Angiostrongylus

Question 25

how can we diagnose a hypercalcaemia caused by PTH on clinical pathology

Answer 25

there will be high calcium and low phosphorous
OR
measure PTH levels

Question 26

if we have azotaemia and hypercalcaemia, how can we tell which one came first

Answer 26

renal dysfunction will have an elevated total calcium but a low ionized calcium

if calcium has caused renal dysfunction, then the ionized calcium will be high as well as the total calcium

Question 27

What is ionized calcium levels like in secondary hyperparathyroidism

Answer 27

low-normal

Question 28

what are ionised calcium levels like in primary hyperparathyroidism

Answer 28

high

Question 29

What is PTHrP

Answer 29

Parathyroid hormone-related protein
produced in malignant hypercalcaemia cases

Question 30

where is 25 hydroxy vitamin D produced

Answer 30

in the liver

Question 31

why would we test calcidiol levels

Answer 31

to look for vitamin D toxicity

Question 32

why would we test calcitriol levels

Answer 32

to look for renal disease or secondary hyperparathyroidism

Question 33

why do we give glucocorticoids to hypercalcaemic patients

Answer 33

some tumours may be steroid sensitive
glucocorticoids also promotes calcium losses

Question 34

why do we give bisphosphanates to hypercalcaemic patients

Answer 34

stops calcium being taken out of bone

Question 35

why do we have to be careful when removing parathyroid adenomas

Answer 35

all other PTH tissues will be atrophied - the animal won’t have enough PTH of its own and we can get a post surgical hypocalcaemia

Question 36

what do we have to give post parathyroid adenoma removal

Answer 36

IV calcium and vitamin D therapy

Question 37

List the 3 categories of hypocalcaemia

Answer 37

parathyroid dependent (primary hypoparathyroidism),
demand exceeds supply or mobilisation,
PTH and calcitriol resistance syndromes

Question 38

List 10 clinical signs of hypocalcaemia

Answer 38

muscle fasciculation/tremors
face rubbing
biting/licking paws
hypersensitivity
stiff gait
ataxia
tetanic seizures
respiratory arrest
weakness
behavioural changes

Question 39

Describe how to treat hypocalcaemia

Answer 39

IV calcium- monitor for bradycardia
oral calcium and vit D for long term