blood pressure measurement in hyperthryoid cats

Re: blood pressure measurement in hyperthryoid cats

Christopher Saul — Wed, 03 Nov 2010 14:12:52 GMT

James - I think your approach is perfectly fine; if I had a cat with signs of end-organ damage ( hence why I always do a fundic exam) or SBP of 250-280, I would also prioritise hypertensive medications first; I would not wait until I had acheived euthyroidism.

Indeed, in animals with concurrent CKD and hyperthyroidism, sometimes it is necessary to withdraw antithyroid medications to spare the kidneys (hyperthyroidism actually increases GFR), and hence one would need to control BP in such patients.

I do think sometimes it can be difficult to get representative SBP measurements in fractious cats ( I mean do you belive the 280mmHg reading?)........ My own method would be not to do SBP measurement in the consult room. I admit the cat for the morning ( pref in a walk in kennel if poss), allow it to acclimatise and calm down, then take SBP measurements in the cage with the cat using the minimum safe restraint.

Chris

Re: blood pressure measurement in hyperthryoid cats

James Allsop — Wed, 03 Nov 2010 13:13:49 GMT

Ive had cats presenting with obvious signs of hypertension - retinal haemorrhage or detachment. I normally priorotise BP measurement and treatment over blood sample initially as I get a little worried that these cats if restrained for a blood sample could spike their BP causing more damage (some of these cats have systolic pressure of 250-280mmhg - southwest medical doppler BP machine). I have gently examined the cat, done the BP - which in my experience is well tolerated by most cats (even hyperthyroid cats), then treated the BP for a week before seeing them again for bloods to find out why they are hypertensive. I would appreciate any feedback from anybody with greater understanding of these patients if im am incorrect in my assumptions with this approach.

Re: blood pressure measurement in hyperthryoid cats

Christopher Saul — Sat, 30 Oct 2010 15:11:22 GMT

yes hypertension can exist even when the cat's hyperthyrodism is otherwise controlled, hence why we should monitor. This is presumably because of underlying chronic kidney disease. In a recent study, 15.3% cats developed azotaemia within 240days of diagnosis and treatment for hyperthyroidism. Of course, treating cats with concurrent hyperthyrodism and CKD can be quite a balancing act

Re: blood pressure measurement in hyperthryoid cats

Julian Earl — Fri, 29 Oct 2010 20:44:26 GMT

I was told on a CPD course hypertension can still develop in hyperthyroid cats even after the condition is undergoing otherwise successful treatment. :shrugs don't know:

Re: blood pressure measurement in hyperthryoid cats

Amanda Magrath — Fri, 29 Oct 2010 17:09:35 GMT

Thank you all for your advice - agreed, the cat in question is very jumpy/nervous and your typical manic hyperthyroid cat so not sure how valid BP measurement will be! I'll definitely do a fundic exam at next consultation though, and will attempt BP hopefully when T4 under control.

Re: blood pressure measurement in hyperthryoid cats

Christopher Saul — Fri, 29 Oct 2010 15:58:45 GMT

Ideally, one would measure BP at all stages; if nothing else it provides additional information regarding the level of control, plus if you detect a very high SBP it may be wise to commense antihypertensive treatment immediately. However , in practice, I make the decision whether to measure on a case-by-case basis; if a hyperthyroid cat is too agressive to get a meaningful SBP upon, what is the point in measuring when you know it will be elevated due to stress?

Moreover, in a proprtion of hyperthyroids, cost is an issue because many are elderly, uninsured cats....sometimes you have to just keep costs at a minimum.

One thing I always do (if it is safe to do so!!) is a quick retinal examination to look for signs of end-organ damage.....

Re: blood pressure measurement in hyperthryoid cats

Utlendigur — Fri, 29 Oct 2010 15:08:39 GMT

You could always do both I agree some hyperthyroid cats are difficult enough to get blood out of, let alone check blood pressure (especially as many of our clients don't present them until they are at the skeletal, dyspnoeic stage). I'd always tended to wait until they were on treatment but my own cat develop retinal detachment and haemorrhages a couple of days after starting on treatment, and she was only in the early stages of hyperthyroidism, so maybe time to change - although, sod's law, she's the only cat I've known who did have problems...

Re: blood pressure measurement in hyperthryoid cats

Mark Holmes — Fri, 29 Oct 2010 14:02:55 GMT

As I generally don't treat hypertension until their T4 is normal I don't tend to measure it until their t4 is normal. I also find it easier to measure when they are not so jumpy and aggressive!