Diabetes in Cats - Factsheet

Diabetes mellitus (common diabetes) is a condition in which glucose sugar is passed in the urine. This happens when there is too much of the glucose in the blood and the excess is then voided by the kidneys.

Glucose is the substance that provides the energy in an animal. It comes from the food, most notably from carbohydrate, but it can also be produced by the conversion of fat. After a meal there is a large surge of this glucose as it is absorbed through the bowel, and this gets stored in the body, under the control of a hormone called insulin, to be used later on bit-by-bit.

CAUSES

In diabetes this hormone is either faulty or deficient. In cats the most usual problem is that the glands that produce the insulin become packed with waste products, squashing the insulin cells so that they can't work. This has two effects:

1. The glucose absorbed from the bowel cannot be stored and is wasted in the urine;

2. Between meals the blood glucose level drops and the body's reserves (fat depots) have to be mobilised, so the cat loses weight.

Cats at most risk are those that are fat as it is the waste product of the fat that does the damage. Fat cats are also less mobile so the turnover of glucose and carbohydrate is slow.

A second major cause of cat diabetes is after pancreatitis. The pancreas becomes inflamed and damages the insulin-producing cells.

Interestingly, in both cases diabetes can be reversed if the cat loses weight and the pancreatitis is treated, but to do so the diabetes has to be diagnosed early so that insulin can be given to 'spare' the cats own insulin-producing cells. So if you think your cat may have this problem then get to a vet quickly!

DIAGNOSIS

A common sign is an increase in thirst and appetite. Weight loss may be noticed too but this is not always obvious. Blood samples and urine samples show very high levels of glucose and confirm the diagnosis. Another form of glucose, fructosamine, is also monitored as the level changes slowly, over 2-3 weeks, thereby giving a longer-term assessment of the severity of the diabetes.

TREATMENT

The first thing to do is to sort out any underlying pancreatitis or other disease.

Then it is important to start insulin as soon as possible to save what remains of the insulin-producing glands. Because insulin is a protein it would be broken down by the digestive enzymes if given by mouth so it has to be injected. Don't panic! It becomes routine!

Most cats require insulin to be given twice daily which can be a hassle but usually fits in with your own daily regime.

Your vet will start your cat on a low dose of insulin initially then do blood tests every few days to see how well it is working. Ideally the blood is taken eight hours after the insulin, so that it coincides with the peak blood-insulin level.

The dose of insulin will then be adjusted until a safe glucose is reached. It is wise to err on the side of caution and keep the glucose levels slightly high to avoid 'hypoglycaemia' ('hypo') which is dangerous. Cats tolerate slightly high glucose levels well and they do not get cataracts, as would happen in dogs and in people.

Besides, getting blood from your cat twice daily just isn't realistic! Nor are urine samples!

FEEDING

Food must be regular and the quantities should be constant so that we know exactly how much energy is being given and can thus calculate how much insulin is needed. Treats and titbits contain energy and will need more insulin. The meals should be spread out through the day, and it is important to make sure they are eaten before any insulin is injected. Most cats 'graze' rather than have set meals – this is ok.

The aim is to provide a regular number of calories a day, and at regular times. So if you feed treats each day then you can go on doing so, provided that you feed the same number every day.

The best foods are those with complex carbohydrates in them, and these include high fibre diets since they release their glucose more evenly and over a longer time period.

PROCEDURE

1. Feed the cat. Make sure the cat is eating. If not then don't give the insulin and consult your vet, even if it only one missed meal.

2. Inject the insulin into the scruff. The needle is so fine that your cat won't feel it. You must be VERY accurate in your dosing as even tiny variations can have a big effect on a small animal like a cat.

3. Keep the insulin in the fridge at all times or it will go off.

OVERDOSE – 'HYPO'

This problem occurs very rarely, but can happen so watch out for it. Signs of an overdose include a cat that is dull and lethargic. The cat may become wobbly and unable to stand, may become very vocal and may salivate. If left untreated the cat will convulse and go into a coma. This is known as becoming 'hypo' (hypoglycaemic).

Any hint of an overdose should be reported to the veterinary surgeon immediately, regardless of it being day or night.

First aid: feed glucose water or honey water if the cat can still swallow. Repeat this every few minutes until the cat comes round and appears normal. Miss the next dose of insulin.

In later stages, when the swallowing reflex has gone, the cat will need an intravenous injection of glucose. There is not much time to act so don't delay.