Fructosamine in cats - how reliable for diagnosing DM?

Re: Fructosamine in cats - how reliable for diagnosing DM?

Holly Lee — Thu, 29 Apr 2010 22:07:23 GMT

Update: (!) O got urine sample at home - 4+ glucose on dipstick, -ve for ketones. Had started the cat on m/d with the advice that the apparent diabetes may be a consequence of another disease process.

Over a week later re-presented as gone off food for few days, with swelling under the chin, drained pus & started antibiotics but swelling worsened - spread over head and one ear full of blood/pus. No oral pathology but restricted jaw opening thought to be due to swelling/pus around TMJs. Started on additional antibiotics and awaiting an FIV/FeLV result whilst trying to beat & identify cause of infection.

My current feeling on the diabetes is that the cat probably has some endocrine pancreatic dysfunction and is being pushed into semi-clinical diabetes by other disease process/s (BG - under GA whilst examining head - was 19mmol/l so still not sky-high).

Any other comments welcomed...

Re: Fructosamine in cats - how reliable for diagnosing DM?

Stuart Jackson — Thu, 29 Apr 2010 21:19:56 GMT

Have you looked for glycosuria?

Re: Fructosamine in cats - how reliable for diagnosing DM?

Richard Carter — Thu, 29 Apr 2010 18:20:41 GMT

[quote user="Holly Lee"]history of marked weight loss over a few months the only abnormality (on a fairly basic biochem + haem + T4 screen) was glucose of 15mmol/l.[/quote]

After checking urine glucose, in absence of really quite spectacular PU/PD would be looking for other causes of weight loss

Re: Fructosamine in cats - how reliable for diagnosing DM?

ms1083 — Thu, 22 Apr 2010 20:29:25 GMT

Very Good article on fructosamine in cats:

Journal of Feline Med & Surgery 2008, 10, pp583-592

Summary:

useful for diagnosis but only a few days of stress/illness is enough to elevate fructosamine very quickly. This means that the actual value is relatively useless but taking paired or multiple samples can show a useful trend.

Frustosamine returns back to normal within 6 days following correction of hyperglycaemia of 29IU but only 2 days following hyperglycaemia of about 17IU. Meaning that, unlike in dogs, fructosamine only really indicates hyperglycaemia for the previous few days in cats.

BUT if well controlled fructosamine should be normal

Re: Fructosamine in cats - how reliable for diagnosing DM?

Laurence Webb — Thu, 22 Apr 2010 19:15:29 GMT

[quote user="Jillian Hall"]

[/quote]

Fructosamine is basically albumin with glucose stuck on it. The fructosamine goes up in the presence of hyperglycaemia becauuse more gets stuck together, but both the albumin levels and the rate of albumin turnover will affect fructosamine levels and how long a time period it gives you information over. Hypoalbuminaemic animals may have normal or even low fructosamine levels even in the face of persistant hypoglycaemia, as will those with a rapid albumin turnover (eg hyperthyroid cats). As you say, animals with a rapid turnover may have a fructosamine that only represents glucose levels over the last 5 days whilst in 'normal' animals it may be up to 3 weeks.

[quote user="Jillian Hall"]

The same CPD notes suggest that fructosamine measurments should completely negate the need for BG curves in cats.

[/quote]

Personally I disagree with that, as fructosamine only indicates the average glucose level during the previous 1-3 weeks and doesn't take account of spikes and troughs. I've had a good example of this in the last month with a dog that had been given increasing insulin doses on the basis of increasing fructosamine levels. A glucose curve showed Sormogyi overswing, so its blood glucose was rapidly plumetting to 2.5mmo/l ish before rebounding to >30. For most of the day it was significantly hyperglycaemic, hence the high fructosamine levels.

I definitely think that fructosamine is very useful, especially in cats where stress hyperglycaemia is a marked problem, and in animals that look stable it can be an alternative to glucose curves, but it's limitations mean that it can't replace them entirely.

Home glucose curves would seem to be the answer for ongoing monitoring, if anyone's got any great tips for getting owners to do them - my success is variable to say the least!

In this instance I'd agree with home collected urine samples. We use Katkor litter which comes with a pipette and sample tube for a pound or two.

Re: Fructosamine in cats - how reliable for diagnosing DM?

James Allsop — Thu, 22 Apr 2010 17:07:43 GMT

cats tolerate hyperglycaemia for long periods without massive side effects so you probably have time to leave the cat for 2-3 weeks and repeat the fructosamine - if its still high then it would add to your suspicion of DM. This might be a suitable case to try with dietary control initially as using insulin may trigger a hypo in a borderline case. If the cat settled at the surgery you could try a curve or if you had a compliant owner you could consider a 24hr curve at home.

Re: Fructosamine in cats - how reliable for diagnosing DM?

Jillian Hall — Thu, 22 Apr 2010 13:32:02 GMT

I have some CPD notes which suggest that fructsamine lvesl in cats are only a reflection of BG over the past 5-10 days, and not several weeks. Thus they could be affected by short-medium term stressors. The same CPD notes suggest that fructosamine measurments should completely negate the need for BG curves in cats.

Personally, Ive always felt more comfortable with curves that will detect hypoglycaemic periods and have had very good success with clients performing these at home (I tend to do curves for dogs in the surgery as stress-effects are usually less pronounced).

In the above bordeline case I'd go with Vikkis option of serial urine samples at home with the cat will hopefully in a non-stressed state.

Re: Fructosamine in cats - how reliable for diagnosing DM?

Vikki Halliday LLB — Wed, 21 Apr 2010 23:58:30 GMT

I'd rely more on urine glucose levels.

Get the cat on catrine or washed gravel and provide the owner with a supply of ketodiasticks and a record card for daily urine testing.

According to my memory of the most recent diabetic CPD I went to, that was the recommendation.

Re: Fructosamine in cats - how reliable for diagnosing DM?

Holly Lee — Wed, 21 Apr 2010 10:29:21 GMT

Thanks for reply. The owner thinks the cat might have been drinking a little more, not managed to get a urine sample yet - is next on the to-do list. Have considered a home glucose test - as a practice we've not had a huge amount of success with that approach but maybe time to try again.

Re: Fructosamine in cats - how reliable for diagnosing DM?

Clive Ansell — Wed, 21 Apr 2010 10:00:06 GMT

I'm just glancing through some recent CPD notes, and all it says is

" single fasting blood sample are of little value. stress can cause hyperglycaemia and levels can reach 20 mMol or higher, which can be maintained for several days if stress is ongoing"

and

" an elevation of fructosamine (>450uMol) indicates there has been significant periods of hyperglycaemia during the previous 2-3 weeks, and changes of severity of hyperglycaemia may not be reflected in the level. periods of hypoglycaemia are not reflected"

I guess it is going to be difficult to differentiate between diabetes and a chronically stressed cat. Your glucose level of 15 mMol is not all that high if the cat was very stressed.

Is the cat stressed at home, and could the owner measure serum glucose in the home if/when the cat is more relaxed using ear prick and a glucometer?

has there been pu/pd, and is there any glycosuria or ketonuria?