Feline diabetes - symptoms and treatment

Symptoms of diabetes

Diabetes develops gradually in cats and it can go unnoticed for a number of weeks. Realizing thatyour cat has diabetes is made more difficult because in cats the early symptoms of the disease can vary. In a short term some cats may gain weight. They become enormously hungry and eat up to three times their normal daily portions. Other cats lose their appetites from almost the moment the disease strikes. Most cats will drink a huge amount of water and urinate it out in the same quantities. Some cats become almost obsessive about water, lurking around taps, hosepipes and garden fountains. Another sign of diabetes that the back legs are weakened, causing the cat to become very wobbly when walking. This is because once the available insulin in the body decreases, glucose in the bloodstream is not broken down into energy. To get that needed energy, the body instead burns up (metabolizes) fat and protein from the muscles. Aat this point, he skin shows signs of thinning and overall fragility. These metabolic changes cause another complication - a condition known as ketoacidosis. (Ketoacidosis is characterised by the accumulation of ketons; organic compounds containing carbon group linked to a carbon atom - as in acetone, for example) Basically, when the body breaks down fat for energy, this makes the blood more acidic.

When the body is burning only fat and muscle, this acidity is passed out of the body in urine, and the cat gets very dangerously dehydrated. There is a quick test which you can do at home using urine keto/glucose strips. Simply immerse the strip in a urine sample from the cat. If the keto/glucose strip shows glucose in the urine that indicates diabetes. If however, the strip is also positive for ketones, get your cat to the vet ASAP. Ketoacidosis is a life threatening condition, because as the level of acidity in the blood increases, the body's dehydration reaches the point where the cat can lapse into a coma. Early signs of ketoacidosis to watch out for are: loss of appetite, vomiting, diarrhea, lethargy, weakness, dehydration, and breathing problems. Cats with ketoacidosis need emergency treatment with fluid therapy and short-acting insulin injections.


Cats younger than seven rarely suffer from diabetes, (though there are always the unfortunate exceptions). In later life diabetes can develop at any time so it is important to know the signs and keep an eye out for them. Discovering diabetes early means that trhe condition can be largely controlled through diet and prompt treatment can even go on to a permanent remission. It all depends on the amount of damageto the beta cells (cells which produce insulin). If the cells are still working moderately well (as in early diabetes) then reducing the body's need for insulin reduces the beta cells' workload to the point where they can cope. However, if the beta cells are irrepbly damaged or killed then the cat will require insulin injections for the restof her life. Diabetes does not necessarily shorten a cat's life but it generally requires strict diet and medication.


Cats' bodies don't need much carbohydrate and cutting the amount of carbohydrates in the diet does most diabetic cats a world of good. In fact an early diagnosis combined with good diet management will allow some cats to be taken off insulin altogether. Why a low carbohydrate, high protein diet is good for cats is because of how these are processed. Both give the body energy, but carbohydrates are digested quickly. This causes a spike in glucose levelsinthe blood soon after the meal. Proteins are slow-burning, giving lower but sustained levels of energy, producing much less glucose and therefore creating much less need for insulin.

Vets recommend a low carbohydrate diet for cats (ideally, a cat should get no more than 3%-9% of its calories from carbohydrates). Dry foods (even the high quality ones) contain a lot of carbohydrates and should be avoided when feeding a diabetic cat. You can get canned foods which are specially designed for diabetic cats, but some normal moist foods can be equally good. Manufactures do not have to give the exact amount of each ingredient on the label, which will probably contain the minimum or maximum level listed. But the estimate will never be precise. Janet and Binky tables give excellent nutritional information about both canned foods and dry foods. These include most cat foods found on the market and are kept up to date. If you would like to make your own calculations for home-cooked food follow the formula below:

  1. Obtain "as fed" or "dry weight" values of protein, fat, carbohydrate, fiber, and phosphorus from the label. Cross check: if you also have values for water and ash, the values of protein, fat, carbohydrate, fiber, ash, and water should add up to 100%.
  2. Calculate the amount of protein, etc, in 100 grams of food by dropping the percent sign. (Example: if a food is 9.5% protein, 100 grams of that food will contain 9.5 grams of protein.)
  3. Calculate total calories by multiplying protein by 3.5, fat by 8.5, and carbohydrate by 3.5, and summing the results.
  4. Calculate the percentage of calories from protein by dividing 3.5*protein by the total calories. Calculate the percentage of calories from fat by dividing 8.5*fat by total calories. Calculate the percentage of calories from carbohydrates by dividing 3.5*carbohydrate by total calories. Cross-check: these numbers should add up to 100%, except for rounding error.
  5. Calculate grams of fiber per 100 calories by dividing fiber by total calories and multiplying by 100.
  6. Calculate mg of phosphorus per 100 calories by dividing phosphorus by total calories and multiplying by 100,000. (The extra 1000 is to change the units of phosphorus from grams to milligrams.)


There are some oral medications available for diabetic cats which have medium to long-lasting effect. The best known of theseis Glipizide. These drugs can have some side effects (they sometimes contribute to liver damage and sometimes harm the pancreas as well). Because drugs of this sort work by making the beta cells produce more insulin they only work in early stages of diabetes when the beta cells are still alive to produce insulin. Many cats show no improvement with those drugs and will have to be switched to insulin. Owners often panic at the prospect of injecting their cats, but are surprised to find that most cats tolerate injections better than oral medications.

Insulin treatment

For most diabetic cats the best regime is a single dose of slow-release insulin administered twice a day, together with a low carbohydrate diet. (Because cats metabolize insulin quickly - faster, for example, than dogs - they usually need more than one jab a day. It is also better for the cat to eat smaller but more frequent meals rather than one big meal. This reduce a risk of a glucose spike. Never medicate your cat till all the tests are done and the vet tells you the appropriate type of insulin and the dose. The vet will also teach you how to inject the insulin. If injections are done well they are quick and completely painless.

Note: This information is for guidance only. It is not intended to replace consultation with a licensed practitioner.

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