hypercalcemia and ckd in a cat

Re: hypercalcemia and ckd in a cat

Andrew Kent — Tue, 25 Feb 2014 10:31:56 GMT

As an after thought to this I would look for ureteral obstruction in this cat, or at least for secondary renal changes (hydronephrosis) on ultrasound as we have seen that in quite a few cats with hypercalcaemia.

Andy

Re: hypercalcemia and ckd in a cat

Andrew Kent — Tue, 25 Feb 2014 10:29:54 GMT

[quote user="HollyK"]but do you think this does not definitively rule out hypercalcemia secondary to ckd?[/quote]

I would say this rules out the hypercalcaemia being as a result of CKD as that should be driven by PTH.

[quote user="HollyK"]preds as they are very likely to be effective at reducing the calcium levels which should help the kidneys?[/quote]

Normally I would probably avoid pred but this cat has a tumour so it is probably the best option.

[quote user="HollyK"]Do you think a tumor hunt is indicated, my feeling is that although I would like a diagnosis, this cat is probably not a candidate for surgery or chemotherapy given the renal dysfunction so would it change what I am doing? [/quote]

I think the owner should be offered the chance to hunt for a tumour, as there is almost certainly one there somewhere and you may get a much better long term outcome if you manage the underlying tumour. If not the owner needs to understand the poor prognosis.

[quote user="robloxley"]How many cases of idiopathic hypercalcaemia do you see in cats, out of interest?[/quote]

We see a handful a year but usually the ones that develop ureteral obstruction secondary to calcium stones, I would guess the uncomplicated ones either are never diagnosed or not referred.

Andy

Re: hypercalcemia and ckd in a cat

Rob Loxley — Tue, 25 Feb 2014 00:05:16 GMT

[quote user="Andrew Kent"]Ultimately this cat has a bad disease, but could improve for a reasonable period of time with appropriate management, and you may improve the renal values as well by treating the tumour.[/quote]

How many cases of idiopathic hypercalcaemia do you see in cats, out of interest?

[quote user="HollyK"]probably not a candidate for surgery or chemotherapy given the renal dysfunction so would it change what I am doing?[/quote]

Does renal dysfunction rule out something more than pred for lymphoma?

Re: hypercalcemia and ckd in a cat

HollyK — Mon, 24 Feb 2014 20:30:35 GMT

When we diagnosed ckd the urea was 43.22, creatinine was 499, phosphate was 2.8 and total calcium was 2.81 - I thought the hypercalcemia was unlikely to be secondary to ckd as it was normal at time of diagnosis and the pth is appropriately low but do you think this does not definitively rule out hypercalcemia secondary to ckd? The phosphate actually came down in response to diet alone but I added renalzin in when the calcium came back high because I thought if it was secondary hyper parathyroid that the phosphate could be normal due to high pth levels - I know now that the pth levels are normal and possibly this logic is flawed anyway? I have found it a bit difficult to find any literature regarding the treatment of hypercalcemia in the face of ckd but is the general consensus to go for preds as they are very likely to be effective at reducing the calcium levels which should help the kidneys? Do you think a tumor hunt is indicated, my feeling is that although I would like a diagnosis, this cat is probably not a candidate for surgery or chemotherapy given the renal dysfunction so would it change what I am doing? Thanks for all your help, I really appreciate it Holly

Re: hypercalcemia and ckd in a cat

Andrew Kent — Mon, 24 Feb 2014 19:18:51 GMT

We have seen a few cats diagnosed with CKD who subsequently were found to have hypercalcaemia. The thing is that if you correct the hypercalcaemia you can dramatically improve the renal function, and these cats also are high risk for things like ureteral obstruction due to calcium stones.

Your cat fits with a hypercalcaemia of malignancy (and doesn't fit with hypercalcaemia due to CKD as ionised high and phosphate normal). Could it have been hypercalcaemic before the diagnosis of CKD?

Ultimately this cat has a bad disease, but could improve for a reasonable period of time with appropriate management, and you may improve the renal values as well by treating the tumour.

If the owner absolutely will not go for further hunting for a tumour I would agree with John and go for steroids for the presumed lymphoma. Keep an eye on the renal parameters whilst you start them but doubt they will change. If that doesn't work you could palliate with clodronate.

Andy

Re: hypercalcemia and ckd in a cat

Martin Atkinson — Mon, 24 Feb 2014 18:56:39 GMT

Firstly I would want to know the actual values of BUN, Creatinine and (original) phosphate were (I assume it was high if you put the cat on Renalzin)before making a decision on whether it was wise to reduce the calcium with preds or frusemide. Secondly the value given for Ca in the test you sent away (3.56) is not much above what I commonly see in older cats with CKD and may be idiopathic. I admit the high ionised calcium and PTHrP throw a spanner in the works for that theory but in the end you have to ask what you're going to do if the client isn't interested in further investigation. While the hypercalcaemia is not causing a clinical issue I'd suck it and see what happens. The low T4 is probably because its a cachectic cat.

I'd worry why a 9 year old cat had CKD though so that may secondary to the calcium issue. Any X-rays to look for soft tissue calcification? Ask the owners if they use skin cream and the cat licks them - a lot of skin creams have high calcium levels.

Re: hypercalcemia and ckd in a cat

John Flynn — Mon, 24 Feb 2014 17:57:43 GMT

[quote user="HollyK"]I am thinking that I need to avoid preds[/quote]

That would have been my first choice treatment for hypercalcaemia of presumed malignancy which is not going to be hunted down.

[quote user="HollyK"]prevent worsening of renal function[/quote]

Are you 100% confident that the renal function is a concern to this cat? It's pretty hard to 100% diagnose chronic kidney disease in a cat wihout excluding hypercalcaemia, and you now have hypercalcaemia... Assuming that kidney disease is present, this may be of minor concern compared to the hypercalcaemia.