Diabetes with Coma in Cats

Diabetes Mellitus with Hyperosmolar Coma in Cats

The pancreas is an organ located in the abdomen, near the stomach. Under normal circumstances, the pancreas makes insulin, a polypeptide hormone that helps to control blood sugar (glucose) levels in the body. When a cat eats food, its blood sugar rises in accordance with the sugars in the food (whether they are natural sugars or not). The pancreas then makes insulin to lower the blood sugar levels to a healthy level. In this way, the other organs in the body are able to absorb and use this sugar for energy.

In the case of diabetes mellitus, the pancreas is not capable of producing enough insulin. When this happens, the blood sugar level remains too high, a condition defined as hyperglycemia. A cat’s body responds to high blood sugar in several ways. First, extra urine is produced and your cat will need to urinate more frequently than usual. Because it is urinating a lot more, it will drink a lot more water, too. Eventually, your cat will be at risk for becoming dehydrated because of the excess urination.

Because insulin helps the body to use sugar for energy, lack of insulin also means that the body’s organs will not receive enough energy. This will make your cat feel hungry all the time, and though it will eat a lot more food, it will not gain weight.

If the diabetic condition is not treated early, your cat's blood sugar level will go higher and higher. Because of the excessively elevated glucose level, even more urine will be made and the cat will become dehydrated due to the loss of fluid. This combination of very high blood sugar and dehydration will eventually affect the brain's ability to function normally, leading to depression, seizures and coma. Coma is rare, however, since symptoms will often warrant a visit to the veterinarian before a pet's health has deteriorated to that level.

Symptoms and Type

Diabetes mellitus without other problems

  • Drinking a lot of water (polydipsia)
  • Urinating a lot (polyuria)
  • Eating a lot but not gaining weight
  • Always seeming hungry
  • Weight loss

Diabetes mellitus with other problems

  • Not wanting to move around much
  • Lack of energy (lethargy)
  • Vomiting
  • Not wanting to eat (anorexia)
  • Lack of excitement or enthusiasm for regular activities (depression)
  • Not responding when called or spoken to
  • Not aware of what’s going on in the environment (stupor)
  • Seizures
  • Confusion
  • Loss of consciousness
  • Coma – long periods with no response to stimuli and inability to be roused


Diabetes Mellitus without complications

  • Pancreas does not make enough insulin

Diabetes Mellitus with complications

  • Pancreas does not make enough insulin
  • Prolonged high blood sugar and dehydration change the way the brain works


Your veterinarian will perform a thorough physical exam on your cat, taking into account the background history of symptoms that you provide and possible incidents that might have precipitated this condition. A complete blood count, biochemical profile and urine analysis will be ordered. The veterinarian will use these tests to determine your cat's blood sugar level, water and electrolyte balance, and how well its internal organs are functioning. These tests will also help your veterinarian to determine if there are any other diseases that might be aggravating your cat's diabetes mellitus.

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