Feline diabetes—personal experience

Recently Neuvians and Berger reported on the nature and standard of diabetes care in cats and dogs in veterinarian practices in the city of Düsseldorf [1]. The estimated prevalence of diabetes is 0.3–1.0% in dogs and 0.1–0.3% in cats. Similar to human diabetes, the incidence of diabetes in pets is expected to rise due to lifestyle changes of the animals with increasing body weight, lack of exercise and longer life expectancy. Their cross-sectional study suggests that much of the current practice in diabetes care for cats and dogs is neither directed to patientorientated goals nor based on adequate evidence with regard to the efficacy and safety of diagnostic and therapeutic interventions. As the owner of two geriatric diabetic cats, I strongly agree with their findings. Being a diabetologist working in a teaching hospital myself, I also have had ample opportunities over the years to compare the different aspects of human and feline diabetes. My first cat, Max, developed diabetes at the age of 11 and presented with the classical symptoms of hyperglycaemia— polyuria, polydypsia and weight loss. Diabetes was confirmed by blood glucose measurement at the vet and he was commenced on twice daily insulin therapy. My cat did not object to the injections at all. Although his polyuria and polydypsia improved, he failed to gain weight and urine test persistently showed heavy glycosuria. I tried changing to a different preparation of insulin with no improvement and attempts to adjust insulin dosage based on urine tests proved extremely difficult and resulted in two episodes of severe hypoglycaemia. Glucose profile at the vet was not informative because cats are notoriously prone to stress-induced hyperglycaemia. In desperation, I resorted to trying home blood glucose monitoring myself. With the help of my diabetes nurse specialists, we chose a glucose meter that required the smallest volume of blood and we attempted to do footpad pricks using a spring-loaded penlet device. Much to our surprise, my cat neither cried nor flinched with this method. Life was revolutionalized by the availability of home blood glucose measurement. What I noticed was that the duration of effect of both intermediate and long-acting insulin preparations was considerably shorter than expected. Even with ultralente, the duration of action was only around 6–9 h and there was not much difference between human and bovine insulin preparations. I eventually discovered why my cat did not gain weight despite improvement of his glycaemic control—he also had thyrotoxicosis! Once we rendered him euthyroid with medical treatment, he put on weight and his diabetes also became a lot easier to control. When my second cat Macavity developed diabetes recently, I was able to see whether some of the observations I made from my first cat applied to other diabetic cats. My second cat developed diabetes after he was given a steroid injection by the vet for his eosinophilic dermatitis. He developed severe symptoms of polyuria and polydypsia 3 days after the steroid injection and he decided to sleep right next to his water bowl rather than in his bed! I did a footpad prick and his blood glucose was well above 20 mmol/ l. I started him on insulin therapy and found that the duration of action of long-acting insulin preparations was again much shorter. As a result, he needed multiple daily injections with a mixture of short-acting and long-acting insulin for a few days to keep his blood glucose down when the steroid effect was at its peak. Unfortunately, his diabetes did not appear to be transient. He needed to stay on insulin therapy even when all the steroid effect had worn off. My first cat has had diabetes for over 5 years now and is still going strong, and the other cat is also doing well. According to my vet, I am lucky in that both my cats are very friendly in nature and easy to handle. It would appear that both the insulin injections and the footpad pricks are not painful as neither of my cats seem to mind at all. Dietary manipulations have proved to be more difficult as both my cats are ‘nibblers’ and it has not been easy to train them to eat after insulin injections. Looking after my diabetic cats has been a unique and interesting experience. Throughout the years, my vet and I have learnt much from each other. I have introduced home blood glucose monitoring to his practice and we have had many discussions comparing human and feline diabetes. My diabetic patients, my medical and nursing colleagues have all shown great interest in my cats. Many of my colleagues and friends have been very helpful and supportive and are willing to step in to give the insulin injections when I am on-call or away on holiday. My two diabetic cats have become the mascots of our diabetes centre.