Feline Diabetes

Diabetes mellitus, is a common disorder in cats and dogs, caused by the inability of the hormone insulin to properly balance blood sugar (glucose) levels.

Glucose is processed by the body into energy. After food is digested, glucose enters the blood stream — in a healthy body, insulin is then secreted signaling the cells to begin the process of converting the sugars into useable energy. As more food is consumed, more insulin is secreted, and the needed glucose is consumed. The pancreas secretes small amounts of insulin — just enough to ensure blood glucose levels don’t rise too high (hyperglycemia) or fall dangerously low (hypoglycemia).

Type 1 diabetes occurs when the pancreas doesn’t produce enough insulin, and type 2 when the body’s cells don’t respond well to insulin. Both result in high blood sugar levels because the body is unable to process the available glucose. In the early stages, diabetics may gain weight as appetites increase and their insulin levels rise and fall. However, in spite of maintaining a good appetite, diabetics ultimately lose weight since the body isn’t able to process sugars into energy. Essentially, diabetics begin to starve to death.

Excessive urination is a classic sign of diabetes in pets, and is likely what led to your diagnosis. Diabetic pets that develop hyperglycemia (high blood sugar levels) will begin passing the excess sugar into their urine (glucosuria). As glucose builds in the urine, the body responds by trying to flush the excess from the kidneys through urination. The condition of excess urination (polyuria, or PU), accompanied by excessive thirst (polydipsia, or PD), are classic signs of diabetes in pets. As you regulate your pet’s diabetes, the PU/PD will become controlled as well.

Although affecting cats of any breed, sex, or age, diabetes mellitus most often occurs in older, obese individuals; males are more commonly afflicted than females. The exact cause of the disease in cats is not known, although genetics, obesity, pancreatic disease, hormonal imbalances, and certain medications are all possible factors.

Signs of Diabetes Mellitus

Polyuria, polydipsia, increased appetite, weight loss, and lethargy are hallmark signs of diabetes in pets. In cats, a disorder called neuropathy that causes weakness in the rear legs is often what led to a diagnosis.

In the earlier stages of the disease, cats remain active and alert with few other signs of disease. However as the disease progresses concurrent conditions often appear, such as poor haircoat, liver disease, and secondary bacterial infections become more common. A dangerous condition called ketoacidosis may develop in some cats, and is discussed elsewhere on this site.

Diagnosis & Treatment

Your veterinarian can determine if your cat is diabetic by checking blood, urine, and clinical signs. You’ll need to build a good working relationship with them to successfully treat the condition together.

Diabetes is not a death sentence. Diabetes in cats is a treatable disorder. Many cat owners are able to control their cat’s condition for years, and the animals lead normal, happy lives. The treatment generally entails giving insulin injections once or twice a day, though a small number may be controlled through diet and oral medication.

People are often initially reluctant to give injections to their pets, but it isn’t really that distressing. Insulin needles are very small, and pets usually do not react at all to getting the shots. When one begins to treat a diabetic cat, their veterinarian will go over all the procedures, including feeding instructions and symptoms of too much or too little insulin and what to do in these cases. The veterinarian will also set up a schedule of regular recheck visits to gauge how the therapy is working and to adjust the insulin dose. A diabetic cat’s need for insulin may fluctuate up and down requiring a change in the insulin dose. Some cats’ needs for insulin will actually cease as the pancreas resumes the secretion of adequate insulin. This reprieve is commonly referred to by owners as a “honeymoon”.


Adequate control of most diabetic cats requires long-acting insulin injections to be given once or twice daily. Each cat responds differently to insulin, so the proper choice of insulin type, dose, and frequency of administration needs to be individually determined. Your vet will likely perform a glucose curve to determine the best regimen. The cat will be hospitalized, given insulin, and then the blood glucose levels will be periodically tested throughout the day. Cats tend to be difficult to maintain on the same regimen for long periods of time, and increases or decreases may need to be made in drug dosages. Too much insulin causes too much of the blood glucose to be used, and results in very low blood sugar. This condition is very dangerous and can kill your cat in hours – your vet will give you detailed information about hypoglycemia  before you begin your insulin regimen.


Be forewarned, diabetes is complex, and trying to understand it all in one big gulp won’t work. Once you’ve made the decision to be a diabetic’s caregiver, focus on one thing at a time — follow your vet’s advice and get the basics straight. Doubt everyone; lots of people will try to give you good advice, but for something as complicated as diabetes, there are few hard and fast rules.

A diabetic cat may live many healthy years with owners who are willing to put forth the effort of monitoring the cat’s condition daily. A cat’s wellness is broadcast by a constellation of behaviors, and the only one who knows him well enough to get the message early is you, who lives with him and cares enough to observe closely and thoughtfully.

If your cat is diabetic and you are deciding whether or not to treat it, consider these facts:

  • Diabetes needs to be treated, or your pet will become more unwell and eventually will die.
  • Your cat will not object to the injections.
  • Insulin can be expensive but one bottle will usually last 4-8 weeks.
  • Treating a diabetic cat is a commitment that you and your family must be prepared to fully take on.
  • Your cat will need have its food, activity, drinking and urination monitored on a daily and weekly basis and will need to have regular veterinary check-ups.

If you are willing to work closely with your veterinarian, you and your cat can have many happy years ahead.