Hypercalcaemia

Question 1

What is the typical signalment of primary hyperparathyroidism in cats?

Answer 1

middle aged to older

Question 2

how do you treat primary hyperparathyroidism?

Answer 2

Normally surgery to remove the affected gland

Use U/S first to see which gland of the 4 is enlarged and guide surgery

Question 3

What are the clinical signs of hypercalcaemia?

Answer 3

Twitching
PUPD
constipation
Cardiac arrhythmias
vomiting
anorexia

Question 4

When is PTHrP high?

Answer 4

In some cases of malignancy induced hypercalcaemia - some cases won’t be high though!

Question 5

What are the main drugs used to manage hypercalcaemia in cats?

Answer 5

Preds or dexamethasone (only do if have a dx)
Frusemide (ensure hydrated)
alendronate - oral long term management
Calcitonin

Question 6

How do steroids reduce high Ca?

Answer 6

Glucocorticoids act to reduce bone resorption, decrease intestinal absorption and increase renal excretion of calcium. Their mechanism of action is thought to be through inhibiting prostaglandin E, osteoclastic activating factor and vitamin D production.

Question 7

How can diet help hypercalcaemia?

Answer 7

in cats with idiopathic hypercalcaemia. High fibre diets can be fed to bind intestinal calcium, thus reducing its absorption. Wet diets can also be helpful in promoting diuresis and generally have a lower calcium content than dry diets. Renal diets may be successful in some cases as these are low in calcium and phosphate, although calcium availability is higher compared with maintenance diets. Renal diets are also more alkalising than normal maintenance diets. However, hypercalcaemia has been noted in cats fed a renal diet and so this diet should be discontinued if hypercalcaemia worsens.

Question 8

What would bloods show in idiopathic hypercalcaemia?

Answer 8

the total and ionised calcium levels are elevated but phosphate, PTH-rp and vitamin D metabolites are normal. PTH may be normal or decreased due to the suppressive effect of hypercalcaemia.

Question 9

How can you treat mild idiopathic hypercalcaemia?

Answer 9

Dietary management may be successful in many cases. Feeding a high fibre diet, supplementing with psyllium husks or feeding a wet diet is recommended as an initial first step, particularly in cats with only mild or moderate hypercalcaemia. A renal diet or diet formulated for management of calcium oxalate urolithiasis can be considered as an alternative

Question 10

What are the calcium results for hypercalcaemic CKD cats?

Answer 10

in cats with early and mid-stage CKD, ionised calcium is normal or low and total calcium is normal or increased. This is the result of increased phosphate concentration associated with reduced renal clearance forming complexes with ionised calcium

Question 11

What would you see on bloods with primary hyperparathyroidism?

Answer 11

increased total and ionised calcium concentrations, increased PTH concentration, decreased phosphate concentration and normal or increased calcitriol

Question 12

How does renal secondary hyperparathyroidism work?

Answer 12

results from reduced renal clearance of phosphate in patients with a decreased glomerular filtration rate. The increasing blood phosphate forms complexes with calcium, resulting in a corresponding decrease in calcium concentration and stimulating PTH production.`

Question 13

Which tumours are most likely to cause hypercalcaemia

Answer 13

2/3 are lymphoma and SCC

Rest is multiple myeloma, bronchocarcinoma, osteosarcoma and fibrosarcoma

Question 14

What would bloods show with malignancy induced high Ca

Answer 14

Both total and ionised calcium are increased in patients with malignancy-associated hypercalcaemia and, therefore, PTH concentration should be low. PTH-rp can be increased, but can also be normal.

Question 15

What will bloods show with hypervitaminosis D?

Answer 15

High Ca and Phos

Low PTH

Question 16

What can cause granulomatous high Ca

Answer 16

mycobacteria, feline infectious peritonitis, toxoplasmosis, Nocardia species, Cryptococcus species and Actinomyces rhinitis in cats.

Question 17

What adrenal disease can cause high Ca

Answer 17

Addisons

Question 18

What can cause false Ca levels on bloods?

Answer 18

Contaminants (e.g. oxalate/ citrate/ EDTA) - false decrease
haemolysis
lipaemia - false decrease
High albumin - false high
Drugs e.g. paracetemol
Inadequate/ excessive sample

Question 19

How can Ca permenantly affect the body

Answer 19

Mineralisation with phos in the soft tissues

Question 20

How does Ca affect an ECG?

Answer 20

Prolongation of PR interval

Shortening of the QT interval

Question 21

Does low USG and azotaemia confirm CKD in hypercalcaemic animals?

Answer 21

no

Question 22

What are non pathologic reasons for high Ca?

Answer 22

Young animals
lab error
spurious

Question 23

What are the transient reasons for high Ca?

Answer 23

Hyperparathyroidism
Granulomatous disease
Skeletal lesions
Neoplasia - e.g. thymoma, lymphoproliferative disease
Hypervitaminosis D or A
Idiopathic (cats)
AKI or CKD
Thyrotoxicosis
Aluminium exposure
Over supplementation

Question 24

What are the most likely dx for high Ca in dogs?

Answer 24

***Neoplasia, often lymphoma or Anal Sac adenocarcinoma
Renal dz
high PTH
Addisons

Question 25

What are the most likely dx for high Ca in cats

Answer 25

Neoplasia Renal Others

Question 26

What are the main forms of ix in high Ca cases

Answer 26

Bloods Imaging - survey radiographs, assess bones, check for tumours, US the neck PTH and PTHrp and vitamin D Biopsies as needed

Question 27

What parasite can cause high Ca?

Answer 27

lungowrm

Question 28

What are the ways neoplasia can cause high Ca?

Answer 28

humoural high Ca of malignancy Caused by malignancies in bone marrow (may see bone pain/ lucencies) Or associated with solid tumours, rare, normal to increased phosphate and ALP

Question 29

What would you see on bloods with PTHrp was high?

Answer 29

High Ca | Low/ normal phos

Question 30

Outline primary hyperparathyroidism

Answer 30

``` Older animals High iCa, ALP, low phos, High PTH Oft can feel a PTH gland nodule/ see it on rads Oft see CaO urolithiasis Tx with Sx ```

Question 31

Outline addisons as a cause of high Ca

Answer 31

mechanism unknown, appears to correlate with degree of K increase 30% dogs, 10% cats Resolves with Tx

Question 32

outline Vitamin D toxicity as a cause of high Ca

Answer 32

Ingestion of psorriasis cream/ jessamine High Ca occurs approx 24 hours after ingestion High phos, sometimes azotaemia Dx - high vitamin D, low PTH, undectable PTHrp

Question 33

outline granulomatous inflammation as a cause of high Ca

Answer 33

D/t calcitriol synthesis by activated macrophages during inflammation e.g. unusual bacteria - nocardia/ actinomyces Granulomatous dermatitis Fungal dz abroad (e.g. hisotplasmosis)

Question 34

What do you need to r/o to dx idiopathic disease in cats - care - not even 100% clear this is a dz in the UK, only in US

Answer 34

``` FIV FeLV -ve Normal t4 normal acid base status imaging clear low normal PTH, undetectable PTHrp Normal vitamin D ```

Question 35

How does calcitonin work as a treatment for high Ca

Answer 35

Decreases Ca release from bone resistance occurs within a couple of days Can cause v/d, often used as a stop ap

Question 36

How do bisphosphonates work as tx for high Ca

Answer 36

Decrease osetoclast activity, takes 1-2d Effective fro many dz Poss can cause renal injury

Question 37

How do glucocorticoids work as tx for high Ca

Answer 37

Decrease bone resorption Increase renal excretion Decrease intestinal Ca Absorption Only use when dx is made

Question 38

What causes of high Ca may respond to steriods?

Answer 38

``` Addisons many neoplasias idiopathic granulomatous dz Vitamin A and D toxicity ```

Question 39

When may bicarb be used as a treatment for hypercalcaemia?

Answer 39

When acidosis is involved | reserved for severe acute high Ca

Question 40

What is the most common cause of primary hyperparathyroidism in the dog?

Answer 40

Adenoma of the parathyroid gland Keeshonds over represented Often over 10