Recognise the Signs of Diabetes in Your Pet

Pet Diabetes Month – November 2011

November is Pet Diabetes Month, heralding a nationwide screening campaign to test the UK’s cats and dogs for diabetes. Diabetes is increasingly common in dogs and cats over 6 years of age, overweight pets, and certain breeds. Pet owners are being encouraged to take part in the nation’s first online screening programme for pet diabetes.

Pet owners simply log onto www.petdiabetesmonth.co.uk during November and complete the assessment; in doing so, they have a chance to win £250 in pet vouchers.

Diabetes mellitus (DM), the clinical name for “sugar diabetes,” is a condition that affects glucose levels in pet blood. DM is caused by either a shortage of the pancreatic hormone insulin or by the body’s cells having trouble responding to insulin properly. Normally, when pets eat, food is broken down into small components that the body can absorb. Carbohydrates are broken down into several types of sugars, including glucose. Glucose is absorbed from the intestines into the blood where it is available to every cell in the body. However, glucose can only enter the cells and be used as an energy source if insulin is present and the cell can respond to it.  Insulin is effectively a ‘key’ that enables glucose to enter cells but it also needs a functioning ‘key hole’ in the cell.

  • Without enough insulin ‘keys’, glucose cannot enter cells, this is type 1 DM.
  • Without functioning ‘keyholes’, glucose cannot enter cells, this is type 2 DM.

Cats usually suffer with type 2 DM.

If glucose cannot enter cells, it builds up in the bloodstream. At high levels, it cannot be retained by the kidneys and passes into the urine where it can be detected. The presence of high glucose levels in the urine increases the risk of urinary tract infections because bacteria use the glucose as a resource. The presence of glucose in the urine draws water with it in a process known as osmotic diuresis. This increases water loss in urine which is consequently balanced by an increase in water intake through drinking.

High levels of glucose in the circulation for extended periods can also cause the development of cataracts in the eyes.

As the cells cannot absorb glucose as an energy source pets are constantly hungry and lethargic, but are malnourished and appear in poor condition. Their bodies turn to other sources for energy such as fat and proteins, resulting in muscle loss. Metabolism of fat results in a waste product called ketones which, in high levels, is toxic to the body.

The brain is reliant upon glucose as an energy source and cannot utilise alternative forms of energy.

The key signs of DM in pets are:

  • Drinks more water than usual (polydipsia)
  • Urinates more often and produces more urine per day resulting in “accidents” outside the litter box (polyuria)
  • Always appears hungry (polyphagia), but maintains or loses weight
  • Is less active or sleeps more (lethargic)
  • Has thinning, dry, and dull hair

DM in cats

Between 1 in 100 to 1 in 500 cats develops diabetes.

Body cells of cats with DM cannot respond to insulin produced by the pancreas, which is sometimes known as insulin resistance.  Vets normally confirm suspicions of DM by checking for persistently high blood glucose levels. This is complicated in cats because, when they are stressed, their blood glucose levels can become elevated quickly producing glucose spikes. Most cats visiting the vet will already have raised glucose levels which could result in cats being inappropriately diagnosed with DM. This is overcome by checking for a glucose complex (in simple terms it is glucose and serum albumin) known as fructosamine which does not rapidly fluctuate like glucose. Blood fructosamine gives an indication of glucose levels over the previous 2 weeks. Vets will sometimes also check cats’ urine for the presence of glucose.

Treatment of DM in cats usually involves twice daily insulin injections and dietary modification. However, each diabetic cat’s requirements are different and vets need to find the correct dose and treatment regimen for each cat.  It may even be necessary for a cat to stay at a veterinary clinic for a few days to enable a vet to monitor its response to treatment.

As all diabetic cats need insulin, owners need to learn how to administer it by injection. Many pet owners are anxious about giving injections, but needles on insulin syringes are exceptionally thin and the volumes injected are very small so cats rarely feel it.

Diet plays an important role in helping to manage cats with DM.  Cats require high levels of good quality protein and are particularly able to utilise protein as an energy source. Many experts consider a high-protein, low-carbohydrate food ideal for a diabetic cat. However some vets consider it more beneficial to leave a cat on its existing diet if it is eating well rather than risk changing it to a new diet and disrupting it. Ideally cats with DM should be offered the same amount of food at the same time every day but some cats prefer eating small amounts throughout the day. If a cat prefers to eat small, frequent meals, vets will probably not try to change the cat’s habit because any disruption can cause fluctuations in blood glucose levels.

A cat’s response to treatment requires monitoring and fortnightly fructosamine samples are often taken to achieve this. Then insulin doses can be carefully adjusted to achieve acceptable management. Owners can also assist in monitoring their cat by weighing it weekly and measuring water intake over 24 hour periods.

Some diabetic cats no longer need insulin after a few weeks or months of treatment, a condition known as clinical remission. However, clinical remission does not mean that a cat’s diabetes has been cured. Care must still be taken with the cat’s diet and lifestyle. Insulin treatment may be required at a later date in cats that have gone into clinical remission.

A complication of persistently high blood glucose concentrations seen in DM may damage nerves in cats, resulting in weakness and muscle loss, usually in the hind legs.

DM in Dogs

Diabetes is as common in dogs as it is in cats with unspayed female dogs twice as likely as male dogs to suffer from diabetes. Dogs develop both type 1 and type 2 DM and display all of the common symptoms of the disease.

Dogs, unlike cats, do not suffer with glucose spike induced by stress, making it easier for vets to make a diagnosis of DM with simple checks for glucose in blood or urine samples. Vets will also frequently check for the presence of ketones, a waste product of fat metabolism. Once a diagnosis of DM is made, the goal in managing diabetes is to keep glucose concentrations regulated, avoid spikes and drops, and to reduce or eliminate the signs of diabetes such as excessive thirst and urination.

Vets need to determine the correct dose of insulin for each dog which may require the dog to be hospitalised so its response to treatment can be monitored. In complicated cases, regular assessments of blood glucose are made to produce a glucose curve determining how the dog is responding to the insulin injections.

The effectiveness of treatment needs to be monitored occasionally by a vet but owners can also assist by regularly weighing their dogs and monitoring their daily water consumption.

A daily routine of exercise and diet is very important for the management of diabetic dogs. They need to have the same energy expenditure and intake every day. A diet with complex carbohydrates helps ensure that glucose is released steadily into the body and minimises large fluctuations.

When entire bitches with DM have seasons the hormonal changes cause even well managed diabetes to become unstable. For this reason most vets will recommend that entire bitches with DM are spayed at their earliest safe opportunity.

Cataract formation is the most common and importantcomplication of canine diabetes and some vets believe it is inevitable and warn owners that their dog will go blind when they diagnose DM.

David Chamberlain, BVetMed., MRCVS.
Veterinary Consultant to PetSafe®

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