Complications of Pet Diabetes

Just like in humans, poorly controlled diabetes can cause health complications for your pet. Anyone who has a pet with diabetes must be aware of the complications that can occur. It’s important for owners of afflicted animals to learn as much as they can about this disease. Being alert to conditions as they develop can prevent problems from becoming more serious.

Three conditions that are common in both dogs and cats are Diabetic Ketoacidosis, Hypoglycemia and Diabetic Neuropathy.

Diabetic Ketoacidosis. All pet owners need to know the symptoms of ketoacidosis in diabetic pets. It can develop in as little time as a week, so it’s important for pet owners be alert to any of these symptoms:

  • Weight loss, accompanied by ravenous appetite
  • Sudden blindness
  • Weakness and lethargy
  • Drinking an excessive amount of water
  • Urinating frequently
  • Dehydration and vomiting
  • Increased respiratory rate
  • Breath smells like nail polish remover

This potentially life-threatening condition is a result of a buildup of an organic acid called ketones in the blood of diabetic animals. Ketones form when the body burns fat for fuel rather than glucose. In the case of diabetics, a lack of insulin renders the body unable to metabolize glucose (sugar) so the body turns to fat reserves for energy. Ketones are normally filtered out by the kidneys and excreted in the urine, however, if an excess of ketones build up, this will cause an electrolyte imbalance. In addition, the pH level of the blood becomes dangerously acidic.

Diabetic Ketoacidosis is a medical emergency. If you suspect your pet has DKA, get them to a vet immediately! If your pet has more than a mild case of Ketoacidosis; intensive care, including intravenous rehydration, correction of electrolyte imbalance, and reversal of high ketones and metabolic acidosis will be needed. You can test for ketones at home using inexpensive urine test strips, and should routinely do so until your animals blood glucose levels regularly fall below a certain level. Be sure to speak with your vet to determine at what level you should check for ketones in your pet.

Hypoglycemia.  Is a condition where abnormally low blood sugar occurs thereby depriving the brain of fuel (glucose). Symptoms of hypoglycemia include:

  • Weakness
  • Listlessness
  • Drooling
  • Loss of coordination
  • In severe cases, seizure and coma

Hypoglycemia is usually caused by an overdose of insulin. Though that doesn’t tell the whole story. The liver and pancreas work together, with the pancreas keeping the blood glucose from going too high and the liver keeping the blood glucose from going too low. An animal on high carbohydrate foods may lose both its normal liver and pancreatic function. This loss of normal liver function is what causes the signs of hypoglycemia. When the animal is switched to low carb foods instead of high carb foods, the liver could resume its ability to make enough glucose to meet the brain’s needs, and signs of clinical hypoglycemia DO NOT OCCUR.

Diabetic Neuropathy.  Diabetic neuropathy results from damage to the peripheral nerves due to high blood glucose levels. This can result in weakness in the back legs. This problem is seen more often in diabetic cats, but it does happen in dogs as well. Owners sometimes mistake this condition as a sign of old age, but it may actually be the first symptom of a diabetic canine.


  • Weakness of hind legs
  • Feet slipping out from under him/her on the floor
  • Walking on the hocks in back (see image) and/or on the wrists in front
  • Lying down more frequently, especially after short walks

Key to preventing and treating this condition is achieving good control of blood sugars. This problem often reverses itself when blood sugar levels are brought under control.

Diabetic neuropathy has also been treated successfully in cats using a supplement of methylcobalamin B12 (note: not to be confused with cyanocobalamin). Methylcobalamin is active in spinal fluid, and as a result, is able to help heal the damaged nerve cells. Treatment may be required for weeks or months, but improvements are usually seen quickly in most cats treated with methyl B12.


Cataracts. Unfortunately, many diabetic canines will develop cataracts and go blind within a year of being diagnosed with diabetes in dogs. High blood sugar levels cause the lens of the eye to become cloudy and opaque, which leads to vision loss.

Dog owners often struggle with the idea of their pets losing their vision, but actually blind dogs get around very well, and can live long and happy lives. Cataract surgery is becoming more common in dogs. Most pets who undergo the surgery do regain their vision.

Uveitis And Glaucoma. This is a complications from cataracts that your pet can also experience. Sometimes when a cataract develops, it leaks protein into the eyeball. This causes severe inflammation, called uveitis. This needs to be treated right away, as it can progress into glaucoma, or cause a detached retina. Vision loss is usually permanent if these conditions develop.

If a pet develops uveitis, cataract surgery is no longer an option, since there is a much higher chance of complications developing as a result of the surgery.

Lowered Resistance to Infection. It’s common for a diabetic dog to have recurring infections. High blood sugar levels create an inviting environment for bacterial growth. More bacteria cause higher blood glucose levels, so it can become a vicious cycle. Dogs with diabetes should be watched closely for evidence of infections, including skin conditions, prostrate infections, urinary tract infections and pneumonia.

Diabetes in canines can be a challenging condition. It’s up to the pet owner to be alert for any of these common complications of canine diabetes so that the pet can be taken to the vet for treatment as soon as possible.


Just as with humans, untreated diabetes in cats can lead to a number of complications. These include pancreatitis, diabetic neuropathy (walking on the hocks), diabetic ketoacidosis, as well as hypoglycemia and kidney failure. Research in humans and mice has shown that organ damage begins to occur when the blood sugar is above 140 (7.8).  Several of the more common complications are described below.

Pancreatitis. Pancreatitis is a condition that causes severe inflammation in and around the duct area. The pancreas is already damaged, to varying degrees, by the time our cats are diagnosed with feline diabetes. Dr. Hodgkins states in her book Your Cat, Secrets to a Longer, Stronger Life; cats with diabetes typically have at least low-grade pancreatitis. As a result, when a cat comes along that is not achieving expected results with insulin, initial thoughts should turn to the likelihood of pancreatitis.

Pancreatitis may be acute or chronic. Acute pancreatitis is a sudden inflammation of the pancreas, where chronic pancreatitis refers to a long-standing inflammation of the pancreas that alters its normal structure and functions. Both forms of pancreatitis can cause serious complications for our cats, some more severe than others. Poor absorption of food, internal bleeding, tissue damage, infection, cysts, fluid accumulation, enzymes and toxins entering the bloodstream, damage to the heart, lungs, kidneys, and/or other organs may occur if left untreated.

It is now suspected that pancreatitis may be a cause of diabetes in cats.  Diabetes develops because insulin-producing cells (the islet cells) of the pancreas become damaged.

Diabetic Nephropathy (Renal or Kidney Failure).  This condition occurs when high levels of glucose damage the glomeruli, which are the filtering structures, in the kidney. The damaged kidneys can no longer remove waste and extra fluids from the blood stream. Eventually, protein will leak out of the kidneys into the urine. Along with achieving regulation of blood sugars to prevent further damage to the kidneys, treatment for kidney failure may involve treatment with drugs such as benazepril (an ace-inhibitor), intravenous fluid therapy, and phosphorus binders.

Hepatic Lipidosis.  This is a serious complication affecting the liver. More common in overweight cats, Hepatic Lipidosis occurs as a result of not eating (anorexia). The body starts to break down fat for energy and if too much fat is broken down, it begins to accumulate in the liver, causing it to swell. Symptoms include refusing to eat, vomiting, weight loss, lethargy, and jaundice (often indicated by a yellowish look to the whites of the eyes, gums and inside the ears).

It is essential that cats with Hepatic Lipidosis eat. This may involve giving appetite stimulants, syringe feeding or inserting a feeding tube if the cat refuses food for 24 hours or more. While Hepatic Lipidosis is rare, it is usually fatal if not treated.

Other Complications of Pet Diabetes

  • Liver disease
  • Cancer
  • Collapsed Trachea
  • Cushings
  • Diabetes Insipidus
  • Heritary/Congenital Disorders
  • Hyperthyroidism
  • Somogyi Phenomenon
  • UTI – Urinary Tract Infection
  • Dental Problems

In addition to the above complications, diabetic cats may also experience vomiting, diarrhea and other stomach upsets.


Many of these studies can be found here: Research Connecting Organ Damage with Blood Sugar Level.