Managing the Feline Diabetic Patient
Cats suffer from type 2 (non-insulin dependant) diabetes mellitus. This is the usual form of the disease in man. Older, overweight, indoor cats are mainly affected, especially those fed dry foods to appetite. Cats cannot “mop up” excess blood glucose after a meal and are thus more resistant to the affects of insulin than dogs.
INVESTIGATION
Diabetes can occur secondary to other diseases. On suspicion of diabetes, we perform a full blood test to check for concurrent problems. We collect a urine sample and check for signs of infection - urinary infections are common at the time of diagnosis. Unlike dogs, diabetic cats may normalise with prompt treatment of the problem.
DIET
The cornerstone of treatment is diet. All diabetic cats should be placed on a tinned high protein diet of 300 Calories/day. Tinned kitten foods are ideal – Felix, Iams or Hill’s kitten formulations work well. The manufacturers will provide information on the calorie content of any food, if asked. 300 Calories is usually about 1 and a half small tins of kitten food. Food should be offered in two equal meals morning and evening. If the cat prefers to graze on small amounts of food throughout the day this is fine. Very overweight cats (ie over 15lb/7 Kg bodyweight) should be fed 210 calories per day until their weight has normalised.
INSULIN INJECTIONS
Although the thought of injecting a pet seems very frightening, it is a technique that is quickly learned. Within days, most people manage without difficulty. Insulin reverses the toxic effects that very high blood glucose levels have on the body. After a while, some cats may no longer need insulin injections to control their diabetes.
We normally use Insuvet PZI insulin twice daily at a starting dose of 1-3iu depending on the size of the cat. It is very important that insulin is stored and handled correctly
Insulin should always be stored in the fridge and used before its expiry date
A fresh syringe should be used for each injection
The bottle should be inverted to suspend the contents before injection – it should not be vigorously shaken
The cat should be injected in the armpit or over the ribs – injections into the thick skin of the scruff may not be properly absorbed.
Please return used syringes to the practice for safe disposal. Please note – veterinary insulin is Prescription Only and is not available across the counter.
MONITORING
The key to successful control of diabetes is regular monitoring. Initially, we check blood glucose daily at a time just before the evening meal. Unfortunately, levels can rise in some cats with the stress of sampling. We thus monitor treatment by measuring fructosamine. This substance gives blood glucose levels over the previous two weeks.
INITIAL STABILISATION – Within two weeks of starting insulin therapy, we would expect the cat to
Have a decreased thirst
Have a stable bodyweight (or slowly declining body weight if obese)
Have no fainting or collapsing spells (hypoglycaemia)
Have a blood Fructosamine value of less than 400 units/ml
CHECK UPS – We examine our diabetic patients at intervals of two months. The check up is carried out at evening surgery prior to the evening meal we check:
Body condition and perform a full physical examination
The urine for signs of infection – provided that the cat has some urine in the bladder to collect at this time
A blood sample is taken and sent for fructosamine estimation
OTHER TREATMENTS
Once the problem of glucose toxicity has been addressed by Insulin therapy, some cats will see a reduction in their requirements for insulin. This may allow their diabetes to be controlled by other means.
Glipizide Tablets – can be given twice daily in conjunction with the kitten food diet. Initially, fructosamine levels should be checked every two weeks to ensure that the diabetes remains under control. After one month of treatment we normally perform a full blood screening test, as this drug can cause side-effects in some cats. With glipizide, it is rare that the blood glucose becomes too low (Hypoglycaemia – a common problem with insulin injections)
Glucobay – This tablet contains acarbose, a substance that slows the absorption of food from the bowel. A half tablet can be added to each meal (it melts into the food). This substance may improve diabetic control when used in conjunction with either Glipizide of insulin.
LOSS OF DIABETIC CONTROL –From time to time, problems will occur with any patient that will result in loss of diabetic control. For example, severe stress or infections will cause resistance to insulin injections or the cat’s own insulin. This is not necessarily a major problem, but further investigation and re-stabilisation are required.
THE IMPOSSIBLE DIABETIC – A few cats may be uncontrollable even with high doses of insulin. It is likely that these cats are suffering from concurrent disease, such as Feline Acromegaly or Cushing’s disease. Diagnosis can be challenging. Currently, there are no good treatments for these diseases and we have to accept only partial control of the diabetic state.
