Diabetes in Cats
Diabetes mellitus
("sugar" diabetes) is a complex and common endocrine
disorder in the cat. It is caused either by insufficient
production of the hormone, insulin, by the pancreas
(type 1 diabetes) or by inadequate response of the
body's cells to insulin (type 2 diabetes). Because
diabetic cats are not able to utilize glucose properly,
they ultimately develop hyperglycemia (high blood sugar
levels) and subsequent glucosuria (sugar in the urine).
The glucosuria leads to polyuria (excessive urination)
and polydipsia (excessive thirst). In spite of
maintaining a good appetite, diabetic cats lose weight
because the body's tissues are unable to utilize glucose
properly. Progression of the disease ultimately leads to
further metabolic disturbances and causes vomiting, loss
of appetite, weakness, and dehydration.
Although affecting cats of any breed, sex, or age,
diabetes mellitus most often occurs in older, obese
individuals; males are more commonly afflicted than
females. The exact cause of the disease in cats is not
known, although genetic predisposition, obesity,
pancreatic disease, hormonal imbalances, and certain
medications have all been incriminated.
After a period of time, a small percentage of
diabetic cats lose their requirement for specific
therapy with either insulin or hypoglycemic medications.
Signs
of Diabetes Mellitus
Polyuria, polydipsia, increased appetite, and weight
loss are hallmark signs of diabetes mellitus in cats. In
the earlier stages of the disease, cats remain active
and alert with few other signs of disease. However as
the disease progresses, poor skin and haircoat, liver
disease, and secondary bacterial infections become more
common. An infrequent disorder called diabetic
neuropathy may cause cats to become progressively weaker
in the rear legs and assume a unique, plantigrade
stance. A dangerous condition called ketoacidosis may
develop in some cats. Signs of ketoacidosis include a
loss of appetite, vomiting, diarrhea, lethargy,
weakness, dehydration, and breathing abnormalities.
Without proper and prompt treatment, this condition
ultimately proves fatal.
Diagnosis
Diabetes mellitus is diagnosed based on the cat's
clinical signs, physical examination findings,
laboratory test results, and the persistent presence of
abnormally high amounts of sugar in the blood and urine.
Treatment
Proper treatment of diabetes mellitus is based on the
severity of the disorder. Cats with ketoacidosis require
intensive care. Treatment includes fluid therapy to
correct dehydration and electrolyte abnormalities, and
short acting insulin. Diabetic cats that are not ill
usually require insulin injections to be given once or
twice daily under the skin, and a carefully controlled
diet. As an alternative to insulin, treatment with an
oral hypoglycemic drug (see below) may be attempted.
Insulin
Adequate control of most diabetic cats requires
long-acting insulin injections to be given once or twice
daily. Each cat responds differently to insulin, so the
proper choice of insulin type, dose, and frequency of
administration needs to be individually determined.
Selection of the appropriate insulin type, dose, and
frequency of administration for an individual diabetic
cat is ideally based on 18- to 24-hour blood glucose
profiles. In order to perform a glucose profile, the cat
is hospitalized, and following insulin administration,
frequent determinations of blood glucose values are made
throughout the day. The proper dose of insulin may
change with time and may need to be adjusted based on
blood glucose profiles, intermittent blood and urine
sugar measurements, and response to therapy.
Overdosage of insulin causes hypoglycemia (low blood
sugar). Signs of this potentially dangerous complication
include weakness, listlessness, incoordination,
convulsions and coma. Left untreated, death may result.
If hypoglycemia develops, the cat should immediately be
offered its normal food if it is able to eat.
Alternatively, a tablespoon of Karo syrup should be
rubbed on the gums or, if the cat can swallow, given
slowly by syringe into the mouth. Never force fingers,
food, or fluids into the mouth of a convulsing or
comatose cat. Your veterinarian should be contacted
immediately if your cat experiences an episode of
hypoglycemia so that further treatment instructions can
be given and a modification of insulin administration,
if necessary, can be made.
Cats requiring excessively high insulin doses
(greater than one to two units of insulin per pound per
day) should be evaluated further. Other diseases may be
underlying or complicating the diabetes mellitus and as
a result, necessitate high insulin dosages. Problems
with insulin injection, poor absorption or too rapid
metabolism of insulin, or even insulin overdose are
potential causes of an apparently excessive insulin
requirement.
Oral
Hypoglycemic Medications
Healthy diabetic cats can sometimes be successfully
treated with a hypoglycemic medication, glipizide.
Glipizide acts by lowering blood glucose, but unlike
insulin, it is given orally. Adverse side effects are
not common but include vomiting, loss of appetite, and
liver damage. If hyperglycemia persists after one or two
months of therapy, or if the cat becomes ill or
ketoacidotic, glipizide therapy should be discontinued
and insulin therapy instituted.
Diet
Obese diabetic cats should lose weight gradually, with
no more than 3 percent of their body weight lost per
week. Your veterinarian will help in tailoring a safe
weight-loss program for your cat. High fiber, high
complex carbohydrate diets are useful, not only by
assisting in weight loss, but by helping to control
blood glucose levels after eating. Underweight diabetic
cats should be fed a high fiber diet only after reaching
their ideal body weight after being fed a high calorie
diet.
Cats receiving insulin once daily should be fed half
the daily food requirement at the time of the injection
and the remaining half at the time of peak insulin
activity (as determined by a blood glucose profile). If
receiving twice daily insulin injections, cats should be
fed half the daily ration at each administration. Cats
receiving oral hypoglycemic medication should be fed a
high fiber diet, but ideally as multiple small meals
consumed throughout the day.
Home
Care
Topics to be thoroughly discussed with your veterinarian
include:
- Insulin storage and handling
- Insulin administration
- Signs and treatment of hypoglycemia
- Diet
- Monitoring at home
Prognosis
Managing a diabetic cat requires good communication
between you and your veterinarian. A diabetic cat may
live many healthy years with owners who are willing to
put forth the effort of monitoring the cat's condition
daily. Cats tend to be difficult to maintain on the same
regimen for long periods of time, and increases or
decreases may need to be made in drug dosages.
Prepared by the Cornell Feline Health Center,
Cornell University, College of Veterinary Medicine,
Ithaca, New York 14853-6401. The ultimate purpose of the
Feline Health Center is to improve the health of cats by
developing methods to prevent or cure feline diseases
and by providing continuing education to veterinarians
and cat owners. Much of that work is made possible by
the financial support of friends. ©1996 by Cornell
University. All rights reserved. Cornell University is
an equal opportunity, affirmative action educator and
employer.
