Diabetes Mellitus in Cats - What You Need to Know
Cats have a well-earned reputation for being somewhat mysterious and enigmatic...with one exception: When your cat is feeling under the weather, they’re likely to let you know about it in one way or another!
It’s important for pet parents to take note of this all-important feedback, especially when it comes to managing serious feline health issues like diabetes mellitus. Recognizing the early warning signs of this chronic and often debilitating endocrine disease can play a huge role in helping you improve your cat’s chances of remission.
To help you recognize those symptoms and navigate this important topic, we’ve put together a guide featuring insight from three leading veterinarians — Better With Cats Veterinary Advisor, Dr. Georgina Ushi Phillips, DVM; Small Animal Veterinarian and Dog Lab consultant, Dr. Sara Ochoa, DVM; and Excited Cats Veterinary Spokesperson, Dr. Maureen K. Murithi, DVM. Together, we will review causes, symptoms, treatments for feline diabetes, so you can provide the best care for your pet.
Diabetes mellitus in cats: What is it?
Diabetes mellitus is one of the most common endocrine diseases among cats, second only to hyperthyroidism. In veterinarian-speak, it’s defined as persistent hyperglycemia and glycosuria due to insulin deficiency. In pet parent terms, says Dr. Ochoa, that means something is preventing your cat's pancreas from producing enough insulin to maintain a normal blood sugar level. And when that happens, cats may experience vomiting, excessive thirst, and a whole host of other diabetes complications.
Types of feline diabetes
As with humans, cats can develop one of three types of diabetes: Types I, II, or III.
According to Dr. Murithi, “All forms of feline diabetes cause elevated glucose levels as a result of the body’s inability to respond to or produce insulin, the hormone that helps cats’ bodies effectively use glucose for energy. When insulin isn’t able to do its job, or when there isn’t enough of it, glucose can build up in the blood.”
- Type I Feline Diabetes occurs when the pancreas isn’t able to produce enough insulin.
- Type II Feline Diabetes occurs when the cat’s body loses sensitivity to insulin. So, even though the pancreas is producing this hormone, the body still can’t use it effectively. This is the most common form in cats.
- Type III Feline Diabetes occurs when insulin resistance develops in association with high concentrations of progesterone or other hormones (like growth hormone or cortisol), which can be overproduced as a result of some disease processes. Type III diabetes occurs when other hormones in the body cause insulin resistance, e.g. during pregnancy, hormone-secreting tumors, etc. This form is the rarest among cats.
How common is diabetes in cats?
There is reason to believe that the prevalence of diabetes in cats is increasing. In 2007, an American study published in the Journal of Feline Medicine and Surgery showed an increase in the number of feline diabetes cases diagnosed over a 30-year period. And in 2016, Banfield Pet Hospital, one of the largest general veterinary practices in the United States, released a report indicating that feline diabetes cases treated in its network of more than 1000 hospitals had increased 18.1 percent over a 10-year period.
However, researchers are still investigating whether those numbers indicate an increase in the number of cats with diabetes or simply an increase in the number of diagnoses, due to growing awareness of the disease.
“It’s estimated that between 0.2 percent and 1 percent of cats will be diagnosed with diabetes during their lifetime,” reports Dr. Phillips. But even then, the numbers don’t tell the whole story. “Many cases of feline diabetes are likely left undiagnosed, which means the prevalence is possibly higher,” Dr. Phillips notes.
Risk factors for developing feline diabetes
Though research on the prevalence of feline diabetes is ongoing, studies regarding causative factors are conclusive: Obesity is undeniably the greatest risk for cats developing diabetes.
A study published in the Journal of the American Veterinary Medical Association reported that obese cats are nearly four times more likely to be diagnosed with diabetes than cats at a healthy weight. And there is strong evidence to suggest that free feeding — giving your cat round-the-clock access to a full food bowl — may cause chronically elevated glucose levels and decreased insulin sensitivity, which are key characteristics of Type II diabetes.
Cats that carry extra weight aren’t the only ones in danger of developing diabetes. Though it’s much less common, cats with pancreatic disorders that impact insulin production face greater risk, as well. For example, repeated bouts of pancreatitis — a common gastrointestinal disorder among cats — may cause enough organ damage to reduce insulin production and lead to diabetes.
“Cancer of the pancreas is another possible condition that can reduce overall insulin production. Some have suggested that up to 19 percent of feline diabetes is related to pancreatic cancer,” says Dr. Phillips.
Age and sex also play a role. According to Dr. Murithi, “Middle-aged and senior cats are more predisposed to diabetes mellitus as compared to younger cats. And male cats are more likely to develop diabetes than females.”
Other risk factors for developing diabetes include physical inactivity, the use of steroids, pregnancy, systemic infection, and chronic kidney disease.
What are the most common signs of diabetes in cats?
Recognizing the warning signs of diabetes can make a big difference when it comes to treating the disease effectively. According to Veterinary Centers of America, Inc., research shows cats that achieve good glucose control within six months of diagnosis (through measures including low-carb diet, insulin injections, blood monitoring, and follow-up exams) had a 60-80% chance of remission, compared to 30% for cats that started treatment later.
So keep an eye out for any of these symptoms, and notify your veterinarian immediately to ensure the proper diagnosis and treatment plan for your cat.
- Frequent urination and increased thirst
If you find yourself wondering, “Why is my cat so thirsty all of a sudden?” that’s a red flag indicating something could be amiss. According to Dr. Phillips, the first and most common symptom of diabetes in cats is a significant increase in thirst and urination. “A cat’s kidneys will work harder to try and remove the excess glucose in the blood by flushing it out of the body and into the urine. Increased urination leads to increased dehydration and thirst,” explains Dr. Phillips.
- Weight loss, despite an increased appetite
“Because a diabetic cat isn’t able to properly absorb energy-providing glucose, its body has to look for other sources of energy and nutrients, says Dr. Phillips. “The body will begin breaking down any available fat and protein from muscle tissue to feed cells, which leads to weight loss.” During this time, diabetic cats may experience increased appetite since their bodies aren’t getting the nutrients they need. But without the ability to make use of glucose, it doesn’t matter how much cats eat...they’re still likely to lose weight. Diabetic cats may also experience a decrease in appetite as the disease progresses, due to issues such as pancreatitis and urinary tract infections, which are common to feline diabetes.
- Hind-end weakness
Cats suffering elevated blood glucose levels often develop weakness in their hindquarters. In the early stages of diabetes, this can be caused by an imbalance of electrolytes due to increased urination. However, if your cat’s blood sugar levels have been elevated for a long time, that hind-end weakness may be more pronounced. Instead of walking normally on the toes of their rear paws, cats may seem almost flat-footed, with everything from the toes to the top of their hock making contact with the ground. This is called plantigrade stance, a later-stage symptom of diabetes. It is often a result of diabetic neuropathy, which is when prolonged high blood sugar levels affect the nerves of the legs and feet. And it is definitely cause for concern. While regulating a cat’s blood glucose can help, some nerve damage may be permanent.
- Wobbling gait
If your cat wobbles when they walk or adopts a gait that looks like they’ve had too much catnip, that could also be a side effect of diabetes. In most cases, the wobbling gait is due to the same diabetic neuropathy that causes hind-end weakness. However, on rare occasions, a diabetic cat that’s already undergoing insulin therapy may develop a wobbly walk due to a phenomenon called the “Somoygi effect.” If the insulin dose is too high, it may cause blood sugar levels to drop dangerously low. The body counteracts the dip by elevating blood sugars once again, which may cause a wobbly walk. For cats already receiving insulin, a wobbly gait could mean that the cat’s blood sugar has gotten too low. This can happen because their insulin dose is too high, they didn’t eat their usual amount, or because their insulin needs have decreased. Whatever the cause, a wobbly gait calls for a conversation with your veterinarian to ensure immediate diabetes treatment or an adjustment to an existing treatment plan.
- Jerking and twitching
Another later symptom of diabetes is jerking and twitching anywhere in the body. This is triggered by the same neuropathy that causes plantigrade gait.
Diagnosis and treatment options for feline diabetes
Not all signs of diabetes are clear-cut and unmistakable. When in doubt, it’s always a good idea to schedule a visit to the veterinarian. Even non-specific symptoms like drowsiness, lethargy, or changes in mood or behavior can indicate diabetes.
However, be aware that you might not get a clear-cut answer right away. According to Dr. Phillips, “Veterinarians can look for elevated glucose in the blood and urine of a cat, but a definitive diagnosis requires veterinarians to look at glucose levels over time.” That’s because it’s not unusual for glucose levels to spike in response to stress (brought on by a visit to the veterinarian, perhaps) or other conditions.
If your veterinarian suspects feline diabetes, additional testing may be required. Fructosamine is a compound formed when glucose combines with proteins, and it doesn’t change minute to minute like blood glucose, so the two together can provide a reliable diabetes diagnosis. Other tests include urine tests (for glucose and ketones) and a blood glucose curve, which measures the blood glucose at various points in the day to track the rise and fall after eating and after insulin.
If testing confirms a diabetes diagnosis, your veterinarian will recommend a course of treatment designed to manage the effects of the disease.
“The most common form of treatment is insulin therapy,” says Dr. Phillips. “Insulin injections are typically given every 12 hours to help cats properly use glucose again.” While the process is relatively straightforward, it does require sticking to a strict routine.
Glucose monitoring is key in your cat's treatment. Your veterinarian will discuss when you should bring your cat in for a blood fructosamine test and/or if you should be monitoring at home with a glucometer.
Diet also plays a role in diabetes treatment for cats. “Make sure your cat is fed a good-quality diet that’s high in protein and low in carbs,” says Dr. Ochoa. A carbohydrate-restricted diet may be necessary to help obese cats achieve and maintain a healthy weight.
There is no known cure for feline diabetes. But diabetic remission (the ability to maintain normal blood sugar levels without intervention) is possible, especially when the disease is diagnosed early and treated effectively.
That’s why it’s so important to stay alert for potential warning signs — frequent urination, rapid weight loss, wobbly gait, weakness, or excessive thirst — and take quick, decisive action to ensure your pet’s health and wellness. And even if no symptoms exist, be sure to keep an eye on your cat’s weight, provide a healthy diet, encourage exercise, and maintain regularly scheduled wellness checkups with your veterinarian to reduce your cat’s risk of developing diabetes.
- Type I Feline Diabetes occurs when the pancreas isn’t able to produce enough insulin.