Cat with suspected hyperparathyroidism

Re: Cat with suspected hyperparathyroidism

Robin Grimmer — Tue, 07 Feb 2012 23:45:16 GMT

I've had one case of confirmed primary hyperparathyroidism in a cat. It was 12 yo and presented with pu/pd. It had unilateral palpable goitre, hypercalcaemia and high PTH. I removed the cervical mass which was confirmed as a parathyroid adenoma. The cat did ok for a while but unfortunately succumbed to renal failure about 9 months later. As Richard says, whip it out quick - hypercalcaemia will quickly cause renal failure.

Re: Cat with suspected hyperparathyroidism

Martin Atkinson — Tue, 07 Feb 2012 18:03:59 GMT

I have but it is currently broken and I wouldn't be confident scanning a parathyroid gland so will probably refer to QMH as an outpatient.

Re: Cat with suspected hyperparathyroidism

Christopher Saul — Tue, 07 Feb 2012 17:25:01 GMT

You're welcome - good luck with it.

Despite all the other options I've mentioned my money is still on primary hyperparathyroidism though. Have you got ultrasound?

Chris

Re: Cat with suspected hyperparathyroidism

Martin Atkinson — Tue, 07 Feb 2012 17:17:32 GMT

Thanks Christopher, I'm planning on running blood tests again especially as there isn't a phosphorous result and for ionised calcium as looking again it was normal from the other vet but I wonder if people collect the sample properly sometimes as I believe it should be in a tube filled to the top so there is no air trapped. I might as well do protein electrophoresis as well while I'm at it.

Re: Cat with suspected hyperparathyroidism

Christopher Saul — Tue, 07 Feb 2012 17:00:15 GMT

[quote user="Martin Atkinson"]It would appear from what you're saying that a parathyroid tumour is unlikely in a cat of this age but surely it wouldn't have had multiple myeloma or malignancies and still be alive at 4 either would it?[/quote]

Yes you're right, I think primary hyperparathyrodiism is indeed far more likely than it being secondary to a neoplasm. I was just thinking aloud really, when dealing with a complicated medical case I find it helpful to have a 'brain storming' session to help form a differential list. After all if it does turn out not to have hyperPTHism then you need somewhere to go next.

I think the first thing you should do is image the neck, and if you find a parathyroid mass then you have your answer. Having said that, before going for surgery then a met check would be indicated, so you'll probably end up imaging the cat anyway.....

Re: Cat with suspected hyperparathyroidism

Alex Gough — Tue, 07 Feb 2012 16:55:18 GMT

[quote user="Martin Atkinson"]This cat has seemingly has had some hypercalcaemia issues since it was a kitten judging by the history of progressive calcification of the cartilage of the ears[/quote]

Is calcification of the ears documented since a kitten? Calcification can happen relatively quickly. I think the results you have on this case so far are pretty much diagnostic of primary hyperparathyroidism. It is definitely hyperparathyroidism of some description by definition given the high PTH, it is unlikely to be renal secondary given the normal renal values, it is unlikely to be nutritional secondary unless on an odd diet (and I would think osteopenia rather than calcification would be seen then), and it is unlikely to be tertiary hyperparathyroidism, without something that would trigger off that situation (renal or nutritional disease).

Sounds like it wants it's parathyroid adenoma out before it causes renal failure.

Alex

Re: Cat with suspected hyperparathyroidism

Richard Fox — Tue, 07 Feb 2012 16:13:32 GMT

Hmm - sounds perplexing that one Martin - your interpretation seems pretty reasonable to me - good luck with it? Have you run it past a intern medicine bod?

Re: Cat with suspected hyperparathyroidism

Martin Atkinson — Tue, 07 Feb 2012 16:08:50 GMT

Thanks for your reply Chris. First to say I have not actually treated this cat yet, it came for a second opinion and as of writing I have only received a rather disjointed history straight from the client file and medication given is from the previous vet. The original vet peformed the tests and took X-rays which apparently showed (I translate from the notes): spinal spondylitis, OA of several joints, hypercalcification of bone and some ligaments and calcification of the kidney cortices and medulla. This cat has seemingly has had some hypercalcaemia issues since it was a kitten judging by the history of progressive calcification of the cartilage of the ears. It would appear from what you're saying that a parathyroid tumour is unlikely in a cat of this age but surely it wouldn't have had multiple myeloma or malignancies and still be alive at 4 either would it? AFAIA it is on a conventional diet, has not been abroad and there is no history of Vit D treatment although it apparenly had Vit E ointment for its ears.

Re: Cat with suspected hyperparathyroidism

Richard Fox — Tue, 07 Feb 2012 14:57:38 GMT

We have had 40 parathyroid adenomas in cats since 2005 and a few carcinomas - (I can't speak for idiopathic) - of those they range from 1 year old to 18 years old with a rough average of around 12 years of age - without looking at all cases I assume they have presented with primary hyperparathyroidism (otherwise they would have been diagnosed as hyperplasia)

Edit: The 1 year old was not obviously hyperparathyroid from the submission details

Re: Cat with suspected hyperparathyroidism

Christopher Saul — Tue, 07 Feb 2012 14:40:20 GMT

Richard - you've seen far more cases of feline primary hyperparathyroidism than I have - what are the demographics? Have you seen one this young?

Chris

Re: Cat with suspected hyperparathyroidism

Christopher Saul — Tue, 07 Feb 2012 14:33:15 GMT

Hi Martin

Firstly I'd agree with your gut feeling of primary hyperparathyroidism here. It is rare in cats but has been described; it is thought of as an older cat thing though and this cat does seem very young for this, so to do you the service of answering your question

[quote user="Martin Atkinson"]Primary hyperprathyoridism in a cat is very rare - anyone any more ideas[/quote]

here are some random thoughts

When faced with a pattern of high PTH and low PTHrP ; the two most likely causes of this pattern would be primary hyperparathyrodism and hyperviatminosis D, so might it be worth revisititng the hitsory and maybe find out if the owners are using any vitamin based skin creams etc which the cat may have got hold of? Your external lab might offer calcitriol assay.

There are one or two things that are even less likely but worth ruling out:

I'd do full body radiography incliding the limbs as well as the axial skeleton to look for osteolytic lesions or granulomas, and also do a serum protein electrophoresis because multiple myeloma can produce hypercalcaemia, I know the low PTHrP makes this unlikely but as far as I'm aware the PTHrP assay is not 100% sensitive so it wouldnt do any harm to run this and make sure.

Has the cat ever been abroad? I'm not sure if any foreign diseases might cause hypercalcaemia or not!

All in all, I think primary hyperPTHish is still your main differential, so if you can rule out the things I've mentioned above I'd definately go ahead and ultrasound the neck, also have a good look at the kidneys (and have a look at liver, spleen and abdo lymph nodes too, I hope this helps

Chris

Re: Cat with suspected hyperparathyroidism

Richard Fox — Tue, 07 Feb 2012 14:22:48 GMT

Martin - it is rare - we get a skewed outlook on diseases

I was only commenting on the pinnal mineralisation not your treatment

Re: Cat with suspected hyperparathyroidism

Martin Atkinson — Tue, 07 Feb 2012 13:00:53 GMT

[quote user="Richard Fox"]

Seems unusual to have prolonged renal disease from an early age that has not progressed to uremia? A chronic excess of phosphorus or a deficit of calcium - should be more obvious on blood results?

Thanks for your reply Richard. Exactly my thoughts, he seems to have diagnosed renal disease purely on calcification of the kidneys which would happen with prolonged hypercalcaemia anyway.

However I would be concerned about the preds and the synergistic effects with the raised PTH and may worsen the pinal mineralisation ?

[/quote]

I confess that I've never seen a case of primary hyperparathyroidism in a cat but the text in Feline Medicine and Therapeutics does suggest corticosteroids and frusemide as treatment for lowering calcium, with saline drips obviously for acute cases but hardly suitable for long term management.

Re: Cat with suspected hyperparathyroidism

Richard Fox — Tue, 07 Feb 2012 12:33:32 GMT

I'm with you in looking for a parathyroid neoplasm - they are rare but they do occurs (having diagnosed them a few times/year). Seems unusual to have prolonged renal disease from an early age that has not progressed to uremia? A chronic excess of phosphorus or a deficit of calcium - should be more obvious on blood results?

However I would be concerned about the preds and the synergistic effects with the raised PTH and may worsen the pinal mineralisation ?