FELINE MEDICINE
2. Glucose Toxicity
The cat is an obligate carnivore and is thought to be
naturally insulin resistant.4 A carnivore uses mainly protein as energy source to maintain metabolic requirements and only a small amount of carbohydrates. Any
excess carbohydrates are stored as fat.7 Many commercial cat foods are high in carbohydrates (> 50%
of calorie content) necessitating higher levels of insulin to be secreted in order to stabilise blood glucose level. Consumption of high carbohydrate foods
is the primary cause of post prandial hyperglycaemia,
promotes obesity and increases pancreatic beta cell’s
insulin secretion.1, 4, 5 Cats are fundamentally carbohydrate intolerant. Persistent hyperglycaemia causes
damage to the insulin secreting beta cells as well as
damage to the insulin receptors on cell membrane thus promoting both an insulin deficiency as well as
peripheral insulin resistance. Glucose toxicity is dose
dependent. The suppression of insulin by glucose toxicity is initially reversible, but will eventually result in
loss of beta cells.
Cats which are poorly controlled for periods longer
than 6 months have a decreased chance of remission.
Normalising the glucose concentration and keeping
it as close to euglycaemia as possible allows recovery
of the beta cells from glucose toxicity in many cases.
This requires insulin. Dietary management alone or
oral hypoglycaemiac will not achieve this.
Longer acting insulins (glargine, PZI or detemir) should
be injected twice a day for optimal diabetic control.
Lente insulins should not be used as their duration
of action is not long enough.3 The starting dose for a
non-ketotic diabetic cat is 0.25-0.5 IU/kg twice a day
subcutaneously and dose adjustments should not occur more frequently than once every 5-7 days.3
Cats that receive adequate insulin therapy and appropriate dietary adjustment early on in the disease process can go into remission and become euglycaemic
or have only minimal requirements of insulin.5,6,8
3. Stress hyperglycaemia affecting monitoring
methods
Blood glucose curves can have significant day to day
variations in cats with poor glycaemic control. Additionally the stress of hospitalisation can cause stress
hyperglycaemia.3
Issue 04 | JULY 2015 | 13