Diabetes in Cats: Signs, Treatment, and the Chance of Remission

Diabetes in cats is common, closely tied to weight, and, caught early, one of the more hopeful diagnoses on the senior-cat list: many cats go into remission and stop needing insulin altogether. It is also the one of the three usual reasons an older cat loses weight while eating well that we have the most power to prevent. Of the possibilities I once turned over for Biscuit, this was the one I understood least at the time, and, as it turns out, one of the most treatable.

As with the rest of these guides, this describes the disease and how it is handled. What your own cat has, and what to do about it, is a conversation for your vet that starts with a blood and urine test.

What diabetes does to a cat

Insulin is the hormone that moves sugar (glucose) out of the blood and into the cells that burn it for energy. In the feline form, which Cornell describes as most commonly the Type II form, the cells stop responding to insulin properly. Glucose builds up in the blood instead of feeding the body, spills over into the urine, and drags water out with it, which is why a diabetic cat drinks and urinates more. The cat water intake calculator shows how much water is normal for her size, which helps you judge whether hers has climbed. It resembles type 2 diabetes in people, and like the human version it is strongly linked to weight.

The signs

Cornell sums up the two that owners usually notice first: weight loss despite a good appetite and increased thirst and urination. VCA rounds the picture out to four main signs: increased thirst, increased urination, weight loss, and increased appetite. The weight loss alongside a healthy appetite is the part that catches people off guard, the same way it does with an overactive thyroid, which is why a senior cat drinking more and losing weight is worth a vet visit rather than a guess at home. A less common but very telling sign shows up when diabetes goes untreated: Cornell notes that in rare cases of uncontrolled diabetes, cats may experience damage to the nerves in the hind limbs, resulting in a "plantigrade" stance of the hind limbs (walking or standing with their hocks on or close to the ground). That flat-footed, hock-down walk is one of the causes of weak back legs in a senior cat.

The weight connection

Weight is where this disease is most open to influence, which is why it is worth dwelling on. Diabetes is the second most common endocrine disease in cats, it turns up more in middle-aged to senior cats and more in males, and it tracks closely with weight. Cornell notes that obese cats are up to four times more likely to develop diabetes than ideal weight cats, and VCA flags cats over about thirteen pounds as high risk. A lean cat is a cat with the odds tilted in her favor.

How diabetes in cats is diagnosed

Diabetes shows up as a persistently high level of glucose in the blood, and the presence of glucose in the urine. There is one wrinkle worth knowing about cats: stress alone can push a cat's blood sugar up at the clinic, so a single high reading is not proof on its own. A fructosamine test, which reflects the average glucose over the past week or two, tells the truly diabetic cat apart from the merely anxious one.

Treatment: insulin and a change of diet

Treatment rests on two things. The first is insulin, usually a small injection once or twice a day, which most cats tolerate far better than their owners expect walking in. The second is diet: a food high in protein and relatively low in carbohydrates helps steady blood sugar, and bringing an overweight cat back to a healthy weight is part of the treatment rather than separate from it. Many owners learn to check blood sugar at home, which takes a lot of the guesswork out of dosing.

The chance of remission

Some cats with diabetes get better. Cornell puts it plainly: with early, aggressive treatment of diabetes, many cats will enter a state of diabetic remission, meaning they are able to maintain normal blood sugar levels without insulin injections. Remission is not guaranteed, and it is likeliest when treatment starts early and the diet and weight are managed well. But a diagnosis of diabetes is not, for every cat, a life sentence of daily injections, and that is a good thing to know on a hard first day.

The emergency to keep in mind

The one urgent thing to hold in your head is the opposite of the disease itself: blood sugar dropping too low, usually from a little too much insulin. VCA is blunt that low blood sugar is a medical emergency. The signs are weakness, lethargy, shaking, unsteadiness, and in severe cases convulsions. If you ever see them, rub a little honey or corn syrup on the gums and call your vet straight away. It is uncommon when dosing is careful, and worth knowing regardless.

What the outlook is

Good, with commitment. VCA calls diabetes a treatable condition, and Cornell adds that the prognosis for a good quality of life is good with adequate management at home. It asks for more daily involvement than the other two diseases, the injections, the monitoring, the steady routine, and it gives a great deal back, sometimes including a cat who no longer needs treating at all.

When to see the vet

Book a visit if an older cat is losing weight while eating well, or is drinking and urinating noticeably more than she used to. If she has already been diagnosed and you see the low-blood-sugar signs above, that is a same-day call, not a tomorrow one.

That is the third of the three now, the small list I once laid out on the kitchen table trying to understand what was happening to Biscuit: kidney disease, an overactive thyroid, and diabetes. Hers turned out to be the kidneys. If I could hand my younger self one thing, though, it would be the unglamorous fact that keeping a cat lean is one of the few real levers we have over any of this. Most of it we can only manage well. Diabetes in cats is the one of those three we can sometimes prevent, and sometimes even reverse.

Sources

• VCA Animal Hospitals, Diabetes Mellitus in Cats
• Cornell Feline Health Center, Feline Diabetes