High Blood Sugar in Dogs

By PetMD Editorial on Jan. 25, 2010

Hyperglycemia in Dogs

A dog with abnormally high levels of glucose in the blood is said to have hyperglycemia. A simple carbohydrate sugar that circulates in the blood, glucose is a major source of energy for the body, of which normal levels range between 75-120mg.

Insulin, a hormone that is produced and released by the pancreas into the bloodstream when glucose levels rise, plays a key role in maintaining normal sugar levels. Low levels or absolute deficiency of insulin results in abnormally high blood sugar levels.

Some of the causes for hyperglycemia may be pancreatitis, and the resulting inability to produce insulin; normally occurring hormones, especially in female dogs; diet; and infections of the body (such as teeth, or urinary tract).

Middle aged and older dogs are more at risk for developing hyperglycemia, and it is more common in female dogs than in males. Any breed can be affected, but some smaller breeds appear to be more disposed, including beagles, cairn terriers, dachshunds, miniature poodles and schnauzers.

Symptoms and Types

Clinical symptoms may vary depending on the underlying disease/condition. Your dog may not be showing any serious symptoms, especially those if the increased sugar is thought to be temporary, hormonal, or stress induced hyperglycemia. Some of the more common symptoms include:

  • Increased thirst (polydipsia)
  • Increased urination (polyuria)
  • Depression
  • Weight loss
  • Obesity
  • Excessive hunger
  • Dehydration
  • Cataract
  • Bloodshot eyes (due to inflamed blood vessels)
  • Liver enlargement
  • Nerve damage in legs
  • Severe depression (in cases of very high blood sugar levels)
  • Non-healing wounds;infection is increased as the excess sugar feeds fungal and bacterial invaders
  • Tissue damage (due to oxidizing [burning] effect of the excess sugar in the tissue)


Other than high stress situations, harmful drug interactions (such as with heartworm medication), and intake of nutritional solutions containing high glucose, the following are potential causes to hyperglycemia:

Low glucose consumption within the body leading to high blood sugar levels

High glucose production

Physiological causes

  • Soon after taking meal
  • Exertion
  • Excitement
  • Stress


  • Infections in the body can drive blood sugar levels high
  • Dental infection
  • Kidney infection
  • Urinary tract infection



A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. Your veterinarian will have the blood samples tested immediately for blood sugar levels. In some cases the only abnormal finding will be the raised blood sugar. This is especially true in cases that are linked to temporary conditions, such as stress or hormones. Unless there is some underlying disease/condition present, the blood test results are usually normal.

Urinalysis may reveal higher sugar levels, pus, bacteria, and an excessive number of ketone bodies in the urine, as seen in diabetes mellitus. Low insulin levels accompanied by high blood glucose levels are also indicative of diabetes mellitus. High lipase and amylase enzyme levels indicate inflammation in the pancreas. In some cases higher liver enzyme levels are also present due to fatty deposits in the liver tissue. Abdominal X-rays and ultrasound may provide important information regarding the underlying disease.

More specific tests may be required to diagnose the underlying cause. You will need to give a thorough history of your dog's health, onset of symptoms, and possible incidents that might have led to this condition. The history you provide may give your veterinarian clues as to which organs are causing secondary symptoms, such as undiagnosed diseases of the pancreas (pancreatitis, amyloidosis). Previous infections may still be present as well, causing a spike in glucose levels. If your dog has had any previous infection in the body, you should tell your veterinarian about them.



As there are number of conditions that can raise blood sugar levels, the treatment depends on correction of the underlying cause. In cases of physiological rise in blood sugar levels, stress will need to be minimized or eliminated.

It is never ideal to attempt decreasing the blood sugar levels abruptly as it may lead to hypoglycemia or lower blood sugar levels. In diabetic patients glucose level fluctuations are common and adjusting the insulin dose or other drugs can help resolve the problem. There are some situations in which glucose levels are high but do not indicate an increase in insulin and can even be worsened by increased insulin doses. Your veterinarian will guide you in determining when to adjust insulin levels.

Living and Management

In case of diabetes, the dog owner’s life-long commitment and compliance is required for proper management of the disease. These animals also require special diets containing less concentrations of sugar. High-protein, low-carbohydrate, low-fat, and high fiber diet is often recommended for these patients. If your dog is diabetic, you will need to strictly follow the treatment guidelines given for your dog to avoid major fluctuations in blood sugar levels.

If insulin has been recommended, it should be injected at the right time and in the right dose. Never change the brand or amount of insulin dosage on your own without prior consultation with your veterinarian.

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