In cats, either a deficiency of insulin or a resistance to insulin causes the diabetes. A number of mechanisms are responsible for decreased insulin secretion or resistance, but most involve destroying islet cells, the cells of the pancreas that produce insulin. Obesity also increases the risk of insulin resistance in cats.
During digestion, carbohydrates are broken down into glucose (a simple sugar), which is absorbed into the bloodstream. Once in the bloodstream, glucose must enter the body’s cells in order to be used for energy. Insulin signals the body’s cells to absorb glucose from the blood.
A lack of insulin (or insulin resistance) creates two dangerous conditions. First, the body’s cells cannot absorb glucose without insulin; they begin to starve despite the abundant glucose. Second, because the body’s cells do not absorb glucose, the blood glucose level remains dangerously high. This excess glucose is eventually excreted from the body through the kidneys. As the glucose passes through the kidneys into the urine, it pulls water with it by diffusion. This causes increased urination, which leads to increased thirst.
With its cells starving for energy, the body begins to break down its protein, stored starches, and fat. In severe diabetes, muscle is broken down, carbohydrate stores are used up, and weakness and weight loss occur. As fat is broken down, substances called ketones are released into the bloodstream where they can eventually cause diabetic ketoacidosis, a severe complication of unregulated diabetes.
Diabetes can develop in cats of any breed, age or gender. However, older, overweight, and neutered male cats are predisposed to developing this disorder. Diabetes often develops gradually, and many owners may not notice the signs at first.
Diabetes Signs to Watch for in your Cat
• Increased thirst
• Increased frequency of urination
• Weight loss despite a good appetite
• Poor body condition/poor hair coat
• Rear weakness (associated with diabetic neuropathy)
Above and below: examples of neuropathy in cats
How is diabetes diagnosed in cats?
Diagnosis of diabetes is based upon the following:
• Complete medical history and thorough physical examination
• Complete blood count (CBC) to check for infection
• Urine analysis to check for glucose and ketones
• Serum chemistry testing to confirm a high blood glucose and to exclude other diseases
• Abdominal X-rays or abdominal ultrasound if complications or concurrent diseases, such as pancreatitis (inflammation of the pancreas), are suspected
Veterinarians diagnose diabetes when cats have high levels of sugar in the blood and urine after fasting. In cats, the blood sugar level commonly increases under stress, such as when drawing a blood sample, and multiple evaluations may be needed to confirm the diagnosis.
How is diabetes treated in cats?
To successfully manage diabetes, you must understand the disease and take daily care of your cat. Treatment involves a combination of the following:
• Proper weight management
• Insulin injections, generally twice daily
• Control of concurrent problems, such as urinary tract infections
Periodic reevaluation is necessary to ensure that the disease is being controlled. Based on these reevaluations, you may have to change your cat’s treatment regimen over time.
Diabetes Home Care
At home care involves administering prescribed medications, including insulin, as recommended. If the insulin is prescribed twice daily, try to give it 12 hours apart and at the same time each day. You should also work with your veterinarian to develop a weight management and feeding plan. Stick to regular feeding times.
Familiarize yourself with insulin, insulin syringes, insulin storage, and insulin handling; your veterinarian can help.
Observe your cat's thirst and frequency of urination. If these remain increased, your veterinarian may need to adjust the insulin dosage.
Checking urine or blood sugar concentrations at home can also be very useful in the regulation of your cat’s diabetes.
Insulin overdose may cause low blood glucose, potentially resulting in disorientation, weakness or seizures (convulsions). If you notice any of these symptoms in an otherwise responsive cat, offer food immediately. If the cat is unconscious, Karo® syrup can be applied to the gums. In either case, call your veterinarian as soon as possible.