Diabetes with other disorders in Cats
Diabetic cat with possible hyperthyroidism
Megacolon
treatment in Diabetic cat - Cisapride
Elevated
liver enzymes in older diabetic cat
Hernia in
adult diabetic cat
Asthma and Diabetes
Diabetes, Insulin
and Cushing's
Cat
with concurrent diabetes and hyperthyroidism
Diabetic cat with megacolon
also see Diabetes
also see Thyroid Problems
also see Liver problems
also see Asthma
also see Cushing's
Diabetic cat with possible hyperthyroidism
Question: Baron is a 20+ domestic Short hair who weighs about 18 lbs, has had diabetes the past 4 years.
He is on 5 units of insulin twice daily and seems to be doing quite well. Last curve was a little high @ 340/191/ 266. 4 weeks prior he was about 240. 150/200 (app)
Note: T4 has been steadily rising. Last reading was 7.5 and one before that was 6 (which was up from 5.5) In the past he has had levels up to 5, but they decreased.
I speculate that the glucose levels papably increase for two reasons:
I allowed him to eat regular Science diet senior along with RD. He had been RD almost exclusively before.
We have him taking cosequin (sic) for arthritis at 1 tablet per day (he probably only ingests about 50-75% because I mix it with his soft food.
The elevating t4 level is the big one. Our Doctor (of more than 25 years) recommends that we start him on a low dose of topozil (1/2 of a 5 mg tablet twice daily).
I normally never question our Doctor, but I am baffled by the high T4 since Baron is showing none of the classic symptoms.
1. He is not overly active--activity level is normal for an older cat--he sleeps a lot
2. He is not eating ravenously--eating has even decreased slightly in warm summer weather
3. His coat (all white) looks great and he grooms himself regularly--in fact he grooms enough to vomit hairballs even though we brush him twice daily.
4. He is alert, responsive, and a little playful
5. Past blood work up to 3 months ago (last general panel) were well within normal limits (BUN etc.).
If treatment is justified, a 5 hour trip to the nearest facility and a week alone would probably harm him greatly, so medication is the only option we can consider. He also has not tolerated medications well (upset stomache)
My questions are as follows:
1. Can the glucosmine elevate blood sugar levels significantly?
2. Is it possible the higher glucose levels are creating the high T4 levels
3. What other diagnostic options are available to confirm the diagnosis
4. What are the risks involved with topozil and the diabetic feline? This last one is particularly of concern. I fear that adding this to his regimen will throw him into a spiral and out of control.
We are taking him for another full panel on Tuesday and plan to visit further with our Doctor.
As always, thank you for your assistance.
Don
Answer: Don-
1) Based on our clinical experiences we think that administering glucosamine can make it hard to accurately measure the blood glucose in some cats. This feeling is not supported by research and has been refuted by one research study -- although this study was funded by one of the manufacturers of these products. We don't think that there is an actual elevation in blood glucose, based on the symptoms of the cats we are testing and based on the fact that in at least two cats, when stopped the glucosamine for a few days, without changing insulin levels, the blood results improved.
So this is a case in which it wouldn't hurt to stop the glucosamine to see what happens to the glucose curve if you want to based on suspicion, but where the only current information suggests that it won't change things.
2) It is more likely that the higher T4 levels are creating the higher glucose levels. It is notoriously difficult to regulate insulin levels in cats with hyperthyroidism. I do not know of any research or information that suggests the opposite situation occurs where glucose levels rise and cause increases in T4.
3) The most accurate test for hyperthyroidism without going to a great deal of trouble is a free T4 by equilibrium dialysis test. This can be be done by Michigan State University's lab and is available from Antech and probably other commercial veterinary labs. There are three other tests that can confirm hyperthyroidism but involve much more work -- the T3 suppression test, nuclear scintigraphy (using radioactive iodine and a camera that can detect it to show that the thyroid is overactive) and thyroid biopsy.
In reality, the total T4 test is very accurate for hyperthyroidism and it is not likely that the test results are wrong, though. If your veterinarian can palpate an enlarged thyroid gland and the total T4 is elevated, the odds of an incorrect diagnosis based on these findings is really low.
4) I don't know of any special risks associated with methimazole (Tapazole Rx) and diabetes, except that adequate control of the hyperthyroidism, based on testing T4 levels, doesn't always control the adverse effect that hyperthyroidism has on controlling blood glucose. I do not know why that is the case. However, it is best to control hyperthyroidism before losing control of the glucose levels, if possible, because it lessens the long term impact of the resistance to insulin that hyperthyroid cats seem to develop over time.
We have had pretty good luck using transdermal methimazole in cats with sensitive stomachs. These are special gels that methimazole is mixed with that are applied topically (usually to the hairless tissue on the inside of the ear) and are absorbed through the skin. This system for delivering the methimazole does not work for all cats but the results are measurable, so it is possible to monitor the success of the medication and to change to another form, if necessary. Compounding pharmacies can make methimazole into transdermal gels. It can also be helpful just to put the methimazole tablet into a small gel capsule that you can buy at a pharmacy, to lessen the chance of a reaction based on the bitterness of the pill itself.
It is not too unusual to have cats who have hyperthyroidism without any clinical signs except gradual weight loss and increased heart rate (some don't even have this sign).
Good luck with this.
Mike Richards, DVM
9/03/2003
Megacolon
treatment in diabetic Cat - cisapride (Propulsid Rx)
Question: My diabetic calico cat continues
with her megacolon problem. She is about 10. After her cleanout last week she was like a kitten
again, but that was short-lived ... after one bowel movement the day after clean-out, she didn't
exhibit peristalsis (sp) again.
I gave her an enema with PetEnema Saturday which
did stimulate her, and again on Monday. And again yesterday, wed.
today she had some diarrhea on her own.
My specialist only sees the colon surgery if she
doesn't get her ability back. I don't want to go that way ... since she is diabetic I should think it
will really mess up her water balance.
I am giving her up to 15 cc of lactulose a day.
I didn't try the Iams low-residue food, should
have done that.
She was doing pretty well on sheba and Wysong dry
until I neglected to give her lactulose ... I got busy and thought maybe we could skip it. Wrong!
But I was only giving her about 4 cc a day ...
Anyway, any new ideas on treatment, and
how to subscribe again.
Thank you very much. Jill
Answer: Jill-
It is still possible to get cisapride (Propulsid Rx) from compounding
pharmacies and many vets feel that it is helpful for megacolon problems. An alternative medication
is ranitidine (Xantac Rx), which seems to have similar effects in some cats. The usual
dosage of cisapride is 1.25 to 2.5mg given 15 to 30 minutes prior to eating and the dosage of ranitidine
is 1 to 2mg/kg every 12 hours.
We have not used the low residue diet much (two patients) but
it is still getting good reviews on the veterinary information sites, such as the Veterinary Information
Network (tm).
It sounds like it will be possible to get back to a situation
in which things are a little more controlled. I sure hope so.
Mike Richards, DVM
1/15/2001
Elevated
liver enzymes in diabetic older cat
Question: Dear Dr. Mike,
I have written to you before regarding my 18 year old diabetic cat
regarding
his licking behavior, etc. I thought he was doing really well
with his
insulin ( 5 units 2x per day, Humulin N 100). However, he had
a follow up
blood test done on Monday. The results came back OK regarding
the diabetes
and the kidneys. His liver enzymes were "off the scale" (his
words). He
called it hepatitis and stated that while the liver test was high before,
they are very high now. Given his age, he felt that a biopsy or anything
invasive would be a bad idea. I agreed. He suggested a
bland diet with a
Vitamin B complex. The unusual thing is that his appetite is
still quite
healthy and he is still demanding his food as well as home made boiled
chicken. This is unusual in liver disease as I have been reading.
The
vitamin complexes that I have seen contain corn syrup or sucrose.
He is
diabetic so this is a problem. My vet said that there is absolutely
nothing
I can do but keep him comfortable and eating. He also could not
say how this
"hepatitis" developed and said it may be connected to the diabetes.
He has
always been an indoor cat. I would appreciate your thoughts on
this.
Thank you so much for your time
Barbara
Answer: Barbara-
We have seen several cats in our practice with hyperthyroidism that
seemed
to be causing elevations in liver enzymes. These cats have a very good
appetite, in most cases, despite the presence of the high liver enzymes.
Sometimes liver enzymes are elevated when only part of the liver is
damaged, which can happen with blood clots disrupting circulation or
when a
tumor is occupying only a portion of the liver. In these cases pets
tend to
feel well despite elevations in liver enzyme levels. I tend to think
that
it is worth considering diagnostic testing, such as ultrasound exam
and/or
biopsy of the liver, but that is a judgment call and your vet knows
the
overall situation better than I do. Testing for hyperthyroidism is
minimally invasive, since only a blood sample is necessary and I think
that
is worth considering, too. If hyperthyroidism is present, treatment
will
often help the liver a great deal.
The usual diets recommended for liver disease are low protein diets,
such
as Hill's l/d or k/d diets and Purina's NF diet, among others. There
may
also be benefits to the liver in using ursodiol (Actigal Rx), which
increases bile flow and in using SAMe (Denosyl-SD4 tm), a supplement
that
seems to help some liver patients.
It is good that your cat continues to have an appetite and to do well
with
the insulin regulation. It is challenging to keep up with all the problems
that can occur in older cats but it is often possible to make them
feel
much better and to live longer with good quality of life, so it is
rewarding, too.
Good luck with this.
Mike Richards, DVM
12/16/2000
Hernia
in adult cat with diabetes
Question: Dear Dr. Mike,
My diabetic 14-year-old kitty, Oliver, has developed an umbilical
hernia. My vet says she's never seen this in an adult cat before
and
thinks it may have been caused by over exertion. It's large enough
that
he needs it surgically repaired. His hind legs have been weak
ever
since he's been dx'ed with diabetes, and I know this is neuropathy.
Do
you have any idea if the neuropathy could cause the umbilical hernia
as
well? Also, have you ever seen this kind of hernia in an adult
cat?
Thank you for your past responses and your ever informative news
letters! Judy
Answer: Judy-
I know of no association between diabetic neuropathy and the formation
of
umbilical hernias and I could not find any references to this in the
Veterinary Information Network database or the surgical texts that
I have.
I think this must be just one of those strange things that happen
sometimes. The good thing is that it is usually possible to repair
an
umbilical hernia with very good hope for it to remain repaired for
life and
that it is usually a short surgical procedure, which is also a good
thing
from a surgical and anesthetic standpoint, so Oliver's prognosis is
good.
Just in case there has been a mix-up, we do sometimes see inguinal hernias
in older pets, both dogs and cats, although much less commonly in cats.
It
is harder to get a strong repair when fixing an inguinal hernia. These
are
most commonly seen in older dogs that are coughing a lot but muscular
weakness in the rear limbs might contribute to the formation of an
inguinal
hernia due to stress in the inguinal region when the legs are not
supporting weight properly. I have about a 60 to 70% success rate repairing
inguinal hernias (about 30 to 40% of pets have recurrences).
I am not sure
if that is a normal average or below normal average for success in
repairing these hernias. If this were the hernia present the prognosis
wouldn't be as good for a long term successful repair but the need
to try
to repair the hernia is greater since inguinal hernias are more likely
to
cause strangulation of the hernial sac contents, which can cause death.
Hopefully you got the name right and Oliver has an umbilical hernia.
Mike Richards, DVM
12/6/2000
Asthma and diabetes
Question: Dear Dr. Richards,
This question pertains to our 6.5 year old indoor cat Lucia. Here's
a
not so brief case history.
On returning from a week long trip several years ago, we found Lucia
to have difficulty breathing, so much so we brought her to an emergency
room
where she stayed overnight. At this point she was diagnosed with
asthma and given
Prednesone and a bronchidilater. All was well for several years
(we
stopped the medicine after a week or two and used as needed) until
this spring,
when her asthma reappeared with a vengeance. She was given Prednesone
again
for a two week period and again her asthma subsided. After returning
from a
weekend away this June, we noticed that Lucia had lost weight, was
not eating much,
and was very lethargic. We brought her to the Vet and was told
that she had
very high glucose levels and keytones in her urine, so much so that
she stayed the
weekend for IV treatment and glucose curves. After several weeks
on Insulin
and Cypro (for the asthma) she seemed well on her way to recovery.
Her eating
habits, however, changed significantly. She would no longer eat
her Nine Lives
that she had eaten all her life. In fact she would cycle through
different types
of food that she would or wouldn't eat. At one point she ate
4 cans of fancy
feast a day, but will not eat that anymore. She incessantly begs
for table
scraps, something she never did before. She seems to cycle between
times of not
eating at all and eating quite a bit. After her Insulin shot,
her ears tend to
get very warm and she likes to lay down on cool surfaces (tile, hardwood),
as
opposed to our bed, where she used to sleep. When we leave for
a weekend, she seems
to not want to eat at all. At this point, I don't think she has
been completely
regulated for the correct Insulin level (we're doing 5 units per day
of
Insulin U), but I can't help but feel there is something else wrong
with
her. Having read about Pancreatisis, it seems like she might
have several of the symptoms.
We are bringing her to the Vet for more blood work tomorrow, but so
far, they can't find any other problems, aside from the diabetes.
Her brother
does not have anything wrong with him, so we've ruled out any infectious
diseases. Any guidance would be greatly appreciated.
Thanks, John
Answer: John-
Pancreatitis is subtle and difficult to diagnose in cats. It is possible
that it is present. Considering the other medical history it
is probably
more likely that the signs you are seeing are due to the diabetes and/or
asthma, though. It is particularly difficult to deal with asthma
in a
diabetic cat due to the problems with regulating cats when
corticosteroids, like prednisone, must be used to treat a secondary
condition.
It is a good idea to try to use alternative therapies to limit the amount
of prednisone that is necessary to control the asthma. Cyproheptadine
is a
good thing to try. Bronchodilators help some cats. Having terbutaline
(Brethine Rx) on hand to deal with crisis situations might also be
a good
idea. In most cats with asthma, occasional use of prednisone or some
other
corticosteroid is likely to be necessary, though.
During the initial few weeks to months of insulin therapy there are
often
problems with variable appetite and cats will often eat a food
one day and
then refuse it the next. Over time, as it is possible to adjust the
insulin dosage to more closely control the glucose levels, there is
usually a
point where the cat goes back to a normal eating pattern. Cyproheptadine
is an
appetite stimulant in cats but it causes depression in the first week
or so that it is used in a lot of cats, so that might be part
of the problem
with the eating pattern, to.
We have not had to deal with sensitivity to insulin very often, but
it
does occur. We usually have seen pain at the injection site that is
consistent,
but it would be possible for other signs to occur, such as flushing
of the
skin, which might be what you are seeing with the ears. Your vet probably
would notice this during the time when Lucia is there but do remember
to
tell him or her about it, too.
One of the hardest problems to deal with in diabetic cats is the effect
of
things like leaving them at the vets or even when leaving them at home
with someone looking out for them. This stresses cats, which makes
them release
more sugar, changes their eating habits and just makes it generally
hard to keep their insulin regulated. This becomes less of a
problem over time, as
everyone adjusts to the use of insulin, but it is really tough early
on
when trying to establish the correct insulin dosages.
This is just something that you have to work through and it does take
a
lot of coordination between you and your vet, so keep in close
contact and
don't be afraid to ask questions and point out problems. This is going
to
be doubly true in Lucia's case since asthma requires the same
sort of
relationship with the vet. Hang in there and things should
improve
with time.
Mike Richards, DVM
11/4/2000
Diabetes,
cushing's and insulin in cat
Q: Dr. Richards,
Thank you for responding to my questions.
Yesterday I was ready to go with PZI, got a consent form,
etc. , but my vet, David Anderson, thinks I am throwing away money.
He used to use PZI, but now he is using the Humulin Ultralente.
I did switch to Humulin Lente two weeks ago, but have not
seen a lot of improvement. I want to try NPH after two more weeks on
Lente.
I hope he will agree.
He believes Calico Cat may have Cushings since she isn't
responding. She has a bloated belly. But the tests for
Cushings
are too costly, etc. So I will try HL and then switch to NPH
for
a final go.
What food do you recommend for diabetic cats?
Last night I tried some brewer's yeast, she licked the plate
clean. This morning the same. Thanks for the info on the wounds.
Wow, that's a big wound you let heal by itself. My vet said he
doesn't suture
them if they are less than an inch. That was good news.
Your news is good too.
I like the phrase you gave me, and will most certainly use it hence
forth.
Thanks for the protocol on that.
A: Jill
I think it is a good idea to give the Lente insulin some time to see
how it
works. Stabilizing cats on insulin can take some time and changing
from one
insulin to another too quickly might mean that you will miss an insulin
dosage that might have worked.
Cushing's disease is unusual in cats but there have been several recent
reports on its occurrence in cats, so it can't be ruled out. It is
a cause
of insulin resistance. Cats with Cushing's disease sometimes don't lose
weight when they are diabetic, which is unusual and serves as an alert
that
it may be a problem. Acromegaly will also induce insulin resistance
in
cats. This is an excess of growth hormone. Testing is sometimes the
only
way to know if acromegaly is present but often there will be a quick
progression to neurologic signs (muscular weakness, incoordination,
circling or seizures). Also, hyperthyroidism can cause insulin resistance.
Cats with both diabetes and hyperthyroidism usually lose a lot of weight
but that can also happen with either disease alone so it isn't as good
an
indication of potential problems. Testing for all of these conditions
would
be somewhat expensive.
A lot of vets remember being told in veterinary school or somewhere
along
the line in their careers that insulin doses of more than 1 unit per
pound
indicate insulin resistance or that insulin dosage should not exceed
1 unit
per pound. I think that the current thinking is that both of these
guidelines are incorrect.
It is very difficult to regulate insulin really well without doing glucose
curves. To do this, blood is drawn just before the morning insulin
dose or
as close to it as possible. Then blood is drawn every two to four hours
for
at least twelve hours. A "curve" is drawn on a chart based on the sugar
levels. The peaks and valleys of this curve give an idea of when the
insulin is most effective, when it is wearing off and whether or not
there
is an excess or deficiency in the insulin dose. Surprisingly, high
blood
sugars at certain times of the day can occur as the result of OVERDOSING
insulin --- there is a rebound effect when the sugar level drops very
low
that will make it go very high later in the day.
Many of our clients, but definitely not all of them, are able to obtain
blood samples from their cats or dogs and run blood glucose tests at
home
using the glucometers that are sold in pharmacies and other places
where
medical supplies are available. If you can do this it is very helpful
in
regulating insulin dosage. We find that putting a little vaseline on
the
edge of the ear, shining a light through the ear and then pricking
a
visible blood vessel along the ear margin will allow enough blood to
be
collected from cats to allow testing. The biggest problem is getting
the
blood onto the little testing machine properly. Sometimes it is necessary
to suck up the sample from the ear margin with a small pipet, which
does
make the process complicated.
I usually think that the best food for diabetic cats is one that they
like
that they will eat consistently. I think that is more important than
most
of the other considerations when it comes to diet for diabetic cats.
However, people that study these things suggest a diet containing moderate
amounts of fiber such as Hill's w/d diet.
We have had a cat in our practice with acromegaly and diabetes but I
don't
remember one with Cushing's disease.
Good luck with this.
Mike Richards, DVM
7/1/99
Cat
with concurrent diabetes and hyperthyroidism
Q: Dear Dr. Mike,
I am a subscriber to Vet Digest and once again require some of your
words of wisdom. My cat, Oliver, is one of the unlucky few who
went
through a treatment of radioactive Iodine to treat his hyper-thyroid
condition and ended up being hypo-thyroid. He went from 9 lbs
to 11 1bs
and was very lethargic. On top of that he's become diabetic.
His
hypo-thyroid condition is responding somewhat to 1.25 tablets of .05mg
levotabs/daily (that's .0625 mg), but he hasn't responded to insulin.
His blood and urine glucose are above 400.
Tonight we are increasing his insulin from 2 units twice daily to 3
units twice daily. (100 units/ml insulin)
I'm wondering if the hypo-thyroid condition and treatment interfere
with
treatment for diabetes. Have you any experience with this?
I know that
hypo-thyroidism is rare in cats and this may be an unusual case.
Also, is it possible that my cat won't respond to insulin at all?
Many thanks in advance.
-Judy
A: Judy-
In human beings, diabetes is more common in patients with hyperthyroidism
than it is in the population as a whole. In cats, a study by Hoenig,
Petersen and Ferguson showed that hyperthyroidism also influenced glucose
tolerance in cats and that hyperthyroid cats were more likely to have
diabetes. In addition, their study concluded that treatment for the
hyperthyroidism did not really help in the treatment of the diabetes
and
that it might even make it worse. There was no mention in this study
of
difficulty in regulating the diabetes in these cats and at least one
other
study (Rand, et. al 1993) suggests that even though there is a link
between
hyperthyroidism and diabetes that the treatment for the diabetic condition
is still straightforward and should be controllable.
We are treating one cat for concurrent diabetes and hyperthyroidism
and so
far, it is doing well.
Veterinarians are very conservative, most of the time, in initial insulin
dosages for cats. There are cats who will experience insulin
shock with as
little as 1 unit of insulin but who have high glucose levels without
any
treatment. So most vets are a little nervous about starting out with
insulin dosages that approximate the "average" treatment dosage. We
have
had cats whose insulin requirements were as high as 25 units twice
a day
--- but it took us several weeks to work up to this dosage because
we
started out with 1 unit twice a day, too. I was at a seminar on endocrine
diseases and the speaker (whose name I can't remember offhand) said
that
there isn't an upper limit to insulin dosage -- you just give as much
as
you have to for it to work.
Hope this helps.
Mike Richards, DVM
6/1/99
Diabetic cat with megacolon
Q: Hello Dr. Mike. I have a 13 year old male cat
who I love dearly. Unfortunately he now has a dual medical problem He is
a diabetic and has been so for almost 3 years, and I have had a difficult
time regulating his blood glucose. I use insulin of course - Humulin -U
100 ultralente, and have been experimenting with the dosage. 4 months ago
he developed megacolon, perhaps related to the diabetes, perhaps independently
caused. I have been treating the megacolon with lactulose ( 2 x daily)
and Propulsid. Dietary regulation is near impossible becasue the cat is
finicky and I must get him to eat in order to give him his insulin. Of
late the medication has not been working too well and he has been getting
enemas as frequently as once a week. At those times he does not eat and
he once went into insulin shock, a scary thing, but we saved him in time.
I have spoken to several surgeons and there is a split in their suggestions-
some say operate now - it is an easy operation and an 85 % chance of full
recovery depite the fact that he is a diabetic. Others say use caution
and try things such as adding bran to his diet. The latter group say this
is a high risk surgery for a geriatric (13) diabetic and only use it as
an absolute last resort. They say try everything possible before surgery.
I am in a quandary as to what to do and which group to believe. Is this
indeed high risk surgery to be avoided if possible? or is it relatively
safe and routine and should I plunge ahead? I would appreciate any advice
that you can give me. Thanks.
A: I am guessing that you have two questions.
First, is the subtotal colectomy a reasonably safe procedure and
does it work?
This is fairly easy to answer. This surgery involves removing nearly
the entire colon and then suturing the two ends that are left back together
to form a much much shorter colon. This ends the fecal impaction problem
in almost all cats in which this surgery is performed. Several studies
have shown success rates greater than 90% which means that these patients
are both surviving and doing well. Because of the complexity of the procedure
and potential for serious complications it probably ranks as medium risk
surgery. The benefits seem to outweigh the risks for any cat no longer
responding to medications such as lactulose. Even when the medications
are working this surgery is reasonable to consider.
Second,
are there increased surgical risks due to the diabetes and difficulties
regulating it in my cat?
Yes, there are. Do they outweigh the benefits? I'm not sure, but I lean
towards thinking they do, providing the surgery is performed by someone
willing to take the measures necessary to protect the health of a diabetic
patient.
Diabetics have special needs when it comes to surgery. Surgery is always
stressful to some degree. Stress can cause problems in diabetic patients.
The surgeon must be prepared to deal with these problems and must have
the full cooperation of the pet owner. Preoperative labwork may be optional
for some surgical patients but not for diabetics. It is important to identify
any pre-existing problems. It is usually better to try to determine what
is causing problems with blood glucose regulation and to try to achieve
stabilization of the insulin dosage prior to surgery but megacolon can
become a serious enough problem all by itself. You may have to elect to
proceed with surgery even if good insulin regulation has not been achieved
-- but try to get that done with the help of your vet prior to surgery.
Anesthetics are generally not a problem in diabetic patients except
that it probably isn't a good idea to use xylazine (Rompun Rx) as an induction
agent.
Find a surgeon who is familiar with operating on diabetic patients and
has experience doing subtotal colectomies. This may mean traveling to a
surgical referral hospital or veterinary school. You should receive pretty
specific instructions about the insulin dosages to administer on the day
of surgery and the surgeon should be equipped to check electrolyte levels,
glucose levels and to treat for low or high blood sugar during surgery
and recovery. Diabetic patients may be a little more prone to infection
and may heal a little more slowly than non-diabetic patients but a surgeon
familiar with the problems should take measures to protect against them,
if it appears to be necessary.
If you take these steps it is only slightly more risky to operate on
a diabetic patient than on a "normal" patient. The limiting factor in your
cat's case is the current lack of control of the insulin levels. If you
can get control of this problem with the help of your vet or perhaps a
specialist your vet can recommend, then surgery becomes a simpler choice.
If you can not gain control over the insulin regulation prior to surgery
it is likely that you will not have control after surgery. Since this is
a serious problem in its own right, it adds a complication to the decision
making.
It is easy to see why you are in a quandary. I hope that this has helped
and not made it worse!
Mike Richards, DVM