Hypercalcaemia Flashcards
What is the typical signalment of primary hyperparathyroidism in cats?
middle aged to older
how do you treat primary hyperparathyroidism?
Normally surgery to remove the affected gland
Use U/S first to see which gland of the 4 is enlarged and guide surgery
What are the clinical signs of hypercalcaemia?
Twitching PUPD constipation Cardiac arrhythmias vomiting anorexia
When is PTHrP high?
In some cases of malignancy induced hypercalcaemia - some cases won’t be high though!
What are the main drugs used to manage hypercalcaemia in cats?
Preds or dexamethasone (only do if have a dx)
Frusemide (ensure hydrated)
alendronate - oral long term management
Calcitonin
How do steroids reduce high Ca?
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.
How can diet help hypercalcaemia?
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.
What would bloods show in idiopathic hypercalcaemia?
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.
How can you treat mild idiopathic hypercalcaemia?
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
What are the calcium results for hypercalcaemic CKD cats?
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
What would you see on bloods with primary hyperparathyroidism?
increased total and ionised calcium concentrations, increased PTH concentration, decreased phosphate concentration and normal or increased calcitriol
How does renal secondary hyperparathyroidism work?
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.`
Which tumours are most likely to cause hypercalcaemia
2/3 are lymphoma and SCC
Rest is multiple myeloma, bronchocarcinoma, osteosarcoma and fibrosarcoma
What would bloods show with malignancy induced high Ca
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.
What will bloods show with hypervitaminosis D?
High Ca and Phos
Low PTH
What can cause granulomatous high Ca
mycobacteria, feline infectious peritonitis, toxoplasmosis, Nocardia species, Cryptococcus species and Actinomyces rhinitis in cats.
