Signs of Too Much (or Not Enough) Insulin in Cats

Updated Sep. 13, 2023
veterinarian listening to an orange cat with a stethoscope

Diabetes mellitus in cats, commonly known as diabetes, is a hormone imbalance disorder. When cats eat, carbohydrates from their food are digested and converted to glucose. Glucose, a sugar, is used by the body as energy and is essential for life. The hormone insulin helps move glucose from the bloodstream into cells, where glucose is used for energy.

A cat develops diabetes mellitus when the pancreas:

  1. Does not produce enough insulin

  2. More commonly, if the body cannot use the insulin made by the pancreas

The result is a high blood glucose (blood sugar) level without the ability to use it as an energy source.

How Can Too Much or Too Little Insulin in Cats Cause a Coma?

If a cat with diabetes is given too much insulin, they may become hypoglycemic (having a low blood glucose level), which can cause a coma.

When left untreated, cats become increasingly hyperglycemic (have a high blood glucose level), which in rare cases can also cause a coma. Diabetic ketoacidosis (DKA) is a much more common consequence of high blood pressure.

Both cases are emergencies and must be treated in a veterinary hospital. Without intervention, cats will not survive. 


If your cat is diagnosed with diabetes, one of the ways you need to manage their health is by administering insulin injections.

While uncommon, if a cat gets too much or not enough insulin, they can fall into a coma. Signs of a coma are:

  • Profound lethargy

  • Unconsciousness

  • Unresponsive to sounds

  • Unresponsive to touch

  • Loss of urine or bowel control

But there are warning signs you can spot before your cat falls into a coma.

Signs of Too Much Insulin in Cats

  • Increased drinking

  • Increased urinating

  • Increased appetite

  • Weight loss

  • “Plantigrade” stance (walking on the hock or sole of the foot instead of the toes)

Signs of Not Enough Insulin in Cats

  • Weakness
  • Vomiting

  • Lethargy/depression

  • Restlessness

  • Loss of balance

  • Disorientation

  • Tremors

  • Seizures

How Veterinarians Diagnose Too Much or Too Little Insulin in Cats

If your pet is having any of the above clinical signs, your veterinarian will likely recommend blood work to better evaluate what could be going on. This will include a blood glucose test.

If the blood glucose is too low, your pet may be diagnosed with low blood sugar (hypoglycemia) but if it is too high, your pet may be diagnosed with high blood sugar (hyperglycemia) or diabetes mellitus. 

Diagnosing a Diabetic Coma

A diabetic coma is confirmed based on history, clinical signs, and blood glucose level readings at the time your cat is affected.

Additionally, a urinalysis checks for byproducts of muscle breakdown (ketones) and urinary tract infections and helps determine the extent of any kidney damage.

A complete blood count checks for other conditions, like severe anemia, that can also cause a coma. A blood chemistry panel will indicate if there is any damage to internal organs, like the kidneys, pancreas, or liver.

Treating a Diabetic Coma in Cats

Cats can die while in a coma or during treatment, so intensive treatment is needed as soon as a coma is diagnosed. Hospitalization is required, to provide breathing support and intravenous (IV) fluids. Treatment is aimed at correcting the abnormal blood glucose level and controlling any other symptoms.

If the cause is hyperglycemia, insulin is administered in smaller, more frequent doses until a normal blood glucose level is achieved.

If the cause is hypoglycemia, a sugar substance called dextrose is administered until the blood glucose level is within a normal range. 

Any underlying diseases found in blood and urine samples are also treated simultaneously. Without treatment, cats will most likely die from diabetes while in a coma.

Recovery and Management of Diabetic Coma in Cats

After a pet suffers a coma, they will not be discharged from the hospital until their blood glucose levels are stable and they are eating, drinking water, and urinating on their own. The length of their hospital stay can range from two to seven days, depending on the severity of their symptoms and how quickly their blood glucose levels can be controlled.

Once a cat is out of a coma and stable, preventing another coma and watching for other symptoms of uncontrolled diabetes are the primary goals of home care.

Prevention of Diabetes with Coma in Cats

To prevent a diabetic coma, you must maintain a healthy blood glucose level in your cat. Routine healthy management of a diabetic cat is possible with the following factors, which are easier to remember with the mnemonic “diabetes:”

  • Diet: Feed higher-protein, lower-carbohydrate diets

  • Inform your veterinarian of changes in:

    • Behavior

    • Activity

    • Diet

    • Urinary habits

    • Response to insulin

  • Avoid diet changes

  • Be consistent with meals (feed the same amount of the same diet at the same time every day)

  • Eliminate treats outside of feeding times

  • Test blood glucose levels at home, as directed by your veterinarian

  • Exams should be scheduled every three to six months when your cat is stable

  • Stay alert for changes in your cat’s behavior

Some diabetic cats will enter diabetic remission and no longer need insulin. It cannot be determined which cats will enter remission and which will require lifelong therapy.

Prognosis for recovery after a diabetic coma is better if the coma was caused by hypoglycemia, and if therapy is started quickly and aggressively.

Diabetes With Coma in Cats FAQs

How do I know if my cat is in a coma?

A cat in a coma will not respond to a strong stimulus like name calling, touching, or loud noises. They may have shallow breathing or may be breathing very slowly, less than 10 breaths per minute. If you notice these signs, take your cat to the emergency vet immediately.

How do you know if your diabetic cat is dying?

A cat in a coma is in a deteriorated state, and if medical care is not started soon, your cat could die. Other signs that your pet is near death include a loss of urine or stool control, shallow breathing, a low temperature, foaming from the mouth or nose, and seizure-like activity (convulsions or rigid limbs).

Can a cat recover from a diabetic coma?

With immediate and very aggressive care in a hospital, cats can recover from a diabetic coma. The prognosis is better if therapy is started early and if the cause is underlying hypoglycemia.

Featured Image: iStock/ilkermetinkursova

Janice Thomas, DVM


Janice Thomas, DVM


Dr. Janice Thomas left Cleveland, Ohio, and headed south for warmer weather and less snow. She completed her medical studies at Tuskegee...

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