Diabetes in Cats

My friends and family know that my cat Jasmine Dandelion is my life and joy. Recently she went in for a geriatric appointment with the vet because she is now an old cat. Her bloodwork showed signs of diabetes mellitus and she is now on insulin shots. We are hopeful that we will have several more years with her if she responds well to the treatment.

“Jasmine” by H. Schofield (CC BY 2.0)

What is Diabetes?

It is an endocrine disorder that affects the pancreas in many different species including humans and cats. It affects the production and utilization of the hormone insulin. Insulin is the hormone responsible for the proper uptake of glucose by the cells. If not enough insulin is produced or the insulin is unable to funciton properly, cells can not absorb and use glucose for energy [3]. This leads to hyperglycemia, high blood glucose levels, which is associated with many health risks.

There are three common types of diabetes, Type 1, Type 2, and Gestational. Type 1 diabetes occurs when the pancreas is unable to produce insulin because the immune system has attacked and destroyed the insulin producing cells within the pancreas. This type of diabetes is typically diagnosed early on and patients must take insulin shots daily to live. Type 2 diabetes typically occurs later in life and is due to the inability to properly utilize the hormone which leads to high blood glucose levels. Gestational diabetes occurs during pregnancy and is usually resolved once the baby is born.

Diabetes Mellitus

Diabetes mellitus, type 2, is what Jasmine has.

Jasmine’s condition was detected by the blood work done at the Marlborough Veterinary Clinic. A urine sample showed signs of glucosuria which is excessive sugar in the urine. I should have noticed that there was something wrong with my cat, she was always laying by the water dish and drinking a lot which I learned was polyuria, excessive thirst, a symptom of diabetes. Jasmine also lost a lot of weight as well, which I thought was due to her becoming an older cat, however, I learned from my veterinarian that although diabetic cats can maintain a good appetite they are unable to utilize the carbohydrates from their food and subsequently they lose weight. Most cats that are diagnosed with diabetes have type 2, diabetes mellitus. It is estimated that 0.2-1% of cats are affected by diabetes [1].

Symptoms of Diabetes in Cats

Initial Signs

  • Weight loss despite healthy/increased appetite
  • Polyuria (excessive urination)
  • Polydipsia (excessive thirst)

Signs of disease progression

  • Poor skin and fur
  • Liver disease
  • Secondary bacterial infections – due to an impaired immune system

Diabetic Neuropathy

This condition develops in cases where the diabetes is left uncontrolled and typically happens to obese elderly cats. The nerves within the hindlimbs become damaged leading to an inability to stand upright. The nerve damage causes the cat to stand in a “plantegrade” stance with their “hock” on the ground [1] as seen below.

Brave Cat” by the London Cat Clinic (CC 2.0)


A serious and fatal disease that typically follows diabetes in older female cats. It results from the build up of acid within the blood which is caused by a build up of ketone bodies. This is a result of insulin dependency, stress, and underlying infections [2]. Symptoms to look out for include vomiting, loss of appetite, diarrhea, lethargy, and respiratory problems. Without immediate treatment this condition is fatal.


Diabetes is diagnosed based on a clinical examination coupled with bloodwork and a urine sample. The glucose concentration is measured in both mediums to determine if there is hyperglycemia. Jasmine’s blood glucose level was at 660, when it should not even be over 200 according to my veterinarian. I am very worried about my cat.

Since glucose curves can be negatively affected by the stress level of the cat sometimes veterinarians will use fructosamine. This molecule is elevated in cats with chronic diabetes and is not affected by the stress level of the cat [1]. It is a good way to determine if the cat really does have diabetes.


While there is no cure for the disease effective insulin therapy will improve their quality of life and prolong the time you have with your fur baby. The goal is to control the disease by maintaining a normal blood glucose concentration, minimizing weight loss and other symptoms of the disease, and normalizing their appetite.

Insulin Therapy

Insulin injections are the most effective method of controlling the disease in cats. The dosage for each cat is specific and can be determined by a glucose curve performed by a veterinarian. This typcially monitors how the cat reacts to the insulin and determines the dosage and how often they need the injections. Injection sites should be rotated so that scar tissue build up does not prevent proper uptake of the insulin by the cat. The glucose curve is done multiple times to ensure that the dose is accurate and that the cat is responding well to the treatment.

Overdosage of insulin is potentially fatal if not noticed right away and corrected. Too much insulin can cause hypoglycemia, which is low blood sugar levels. Symptoms include weakness, incoordination (like a drunk person), convulsions, coma, and if left untreated, death. If these signs are noticed, offer the cat normal food stuffs to increase their blood glucose levels. Do not attempt to force water or food into the mouth of a convulsing or comatose cat. A visit to the veterinarian is a good idea if this condition appears in your cat.

Jasmine is on Vetsulin which an insulin approved for dogs and cats.

Dietary Considerations

A veterinarian will help tailor a diet specifically for your cat. Obese cats should not drop too much weight too fast. For the obese cats, a high fiber, complex carbohydrate diet will aide in regulating blood glucose levels. Cats should be given their food before they recieve their shots so as to avoid hypoglycemia. Meal planning and the administration of the shots should be put onto a schedule that will be created and explained by the veterinarian.


[1] CVM. “Feline Diabetes.” Cornell Feline Health Center, Cornell University College of Veterinary Medicine, 23 July 2018, potentaiwww.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-diabetes.

[2] “Diabetes with Ketone Bodies in Cats.” PetMD, 2020, www.petmd.com/cat/conditions/endocrine/c_ct_diabetes_with_ketoacidosis.

[3] NIH. “What Is Diabetes?” National Institute of Diabetes and Digestive and Kidney Diseases, U.S. Department of Health and Human Services, 1 Dec. 2016, www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes.

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