Hypercalcaemia in a CKD cat

Re: Hypercalcaemia in a CKD cat

Anthony Todd — Wed, 19 Nov 2014 19:23:00 GMT

Thanks Andy

Re: Hypercalcaemia in a CKD cat

Andrew Kent — Wed, 19 Nov 2014 19:18:10 GMT

The aim, clearly, is to prevent them from recurring and if you normalise the calcium then usually we are successful (unless there is another reason for them to form). They can still have significant underlying pathology from the presenting episodes which can complicate matters. We usually try diet first and then go for drugs if the calcium remains high.

Andy

Re: Hypercalcaemia in a CKD cat

Anthony Todd — Wed, 19 Nov 2014 14:08:34 GMT

[quote user="Andrew Kent"]They are usually calcium oxalate[/quote]

Do they recur when you reduce the [Ca++] or when you change the diet or do you do both?

Re: Hypercalcaemia in a CKD cat

Andrew Kent — Wed, 19 Nov 2014 13:49:00 GMT

[quote user="Anthony Todd"]What composition of stone or crystal blocks them?[/quote]

They are usually calcium oxalate

Re: Hypercalcaemia in a CKD cat

Anthony Todd — Wed, 19 Nov 2014 13:34:03 GMT

[quote user="Andrew Kent"]we see come for ureteral obstruction[/quote]

What composition of stone or crystal blocks them?

Is it different from the usual?

Re: Hypercalcaemia in a CKD cat

Andrew Kent — Wed, 19 Nov 2014 13:21:46 GMT

Difficult to know overall the percentage of idiopathic hypercalcaemics that get problems as we tend to see the ones that have problems at diagnosis. It is reported that up to about 1/3rd of idiopathics might get urolithiasis. Our percentage is much higher but most of the cats we see come for ureteral obstruction etc. This doesn't seem to be completely dependent on severity of hypercalcaemia.

We also see azotamia and renal disease as a result of hypercalcaemia.

But I am sure there are many cats around with hypercalcaemia that we never know about!

Andy

Re: Hypercalcaemia in a CKD cat

Martin Atkinson — Wed, 19 Nov 2014 09:48:31 GMT

[quote user="Andrew Kent"]And hypercalcaemia on its own can be damaging also so should be managed if possible.[/quote]Although I have seen some severe problems associated with hypercalcaemia when there is a disease process, IME mild idiopathic hypercalcaemia in cats seems to have no detectable deleterious effects. What percentage of these cat will suffer from associated problems in your experience Andrew and what would these predominantly be?

Re: Hypercalcaemia in a CKD cat

Andrew Kent — Tue, 18 Nov 2014 21:04:29 GMT

[quote user="Martin Atkinson"]Trying to manage the hypercalcaemia with steroids and or diuretics only risks worsening the CKD with no benefit.[/quote]

That is true but there are ways to manage idiopathic hypercalcaemics with other drugs (most commonly alendronate) which shouldn't be detrimental to CKD. And hypercalcaemia on its own can be damaging also so should be managed if possible.

Re: Hypercalcaemia in a CKD cat

mariette asselbergs — Tue, 18 Nov 2014 20:56:23 GMT

Especially as long as ionised Ca X P is smaller than 5.

Mariette

Re: Hypercalcaemia in a CKD cat

Martin Atkinson — Tue, 18 Nov 2014 14:55:48 GMT

I wouldn't argue against any of the above advice and I think you have to do the tests but in my experience these usually turn out to be idiopathic. Trying to manage the hypercalcaemia with steroids and or diuretics only risks worsening the CKD with no benefit.

Re: Hypercalcaemia in a CKD cat

Kate Richardson — Mon, 17 Nov 2014 08:02:34 GMT

The only other thing I would add to Andrews advice is check what the albumin level is as well and also recheck the calcium level prior to running PTH etc to ensure the hypercalcaemia is persistent and wasn't a one off spurious result

Re: Hypercalcaemia in a CKD cat

Andrew Kent — Sun, 16 Nov 2014 19:03:55 GMT

Hi Steph,

I hope all is well.

I think your plan for the moment sounds a good one - what we need to try and pick apart is whether this hypercalcaemia is related to CKD or another reason.

Presumably calcium has been measured in previous bloods since the CKD was diagnosed and has been normal (this is important as hypercalcaemic cats can be azotaemic).

If this is renal related in most cases the ionised calcium will be normal and is hypothesised to be due to binding of calcium to retained ions. In those cases generally we don't treat them. But other mechanisms also occur (renal secondary hyperparathyroidism) which may be driven by the phosphate. If it is related to something else then we may need to manage it.

I would avoid steroids until you know more about the aetiology as they could worsen the CKD or make other diseases difficult to diagnose. The exception to this might be if the owners are not keen on additional investigations.

When you are taking the blood for the iCa/PTH I would get the lab to hold the extra blood in case you want to measure PTHrp at a later date. It would also be worth questioning the owners about sources of vitamin D (diet, skin creams etc).

Hope that helps - let us know what you find on the bloods.

Andy