Hypoglycemia (Low Blood Sugar) in Dogs


Overview of Canine Hypoglycemia (Low Blood Sugar)

Hypoglycemia is defined as a blood glucose or blood sugar concentration of less than 70 milligrams per deciliter(mg/dl) of blood. Symptoms depend on how quickly the blood glucose concentration decreases but rarely occur until it falls below 50 mg/dl.

Symptoms reflect the rate of decrease of the blood glucose concentration, the underlying cause of hypoglycemia, and the chronicity of the problem. One common form of hypoglycemia is called juvenile hypoglycemia because it occurs in puppies less than three months of age. Juvenile hypoglycemia is common in puppies because they have not fully developed the ability to regulate their blood glucose concentration and have a high requirement for glucose. Stress, cold, malnutrition, and intestinal parasites are problems that may precipitate a bout of juvenile hypoglycemia. Toy breed dogs less than three months of age are most commonly affected.

Other causes of hypoglycemia include fasting before vigorous exercise, which may be a factor in the syndrome called “hunting dog hypoglycemia”; Addison’s disease, an endocrine problem caused by a lack of hormone production by the adrenal glands which can cause weakness, vomiting, diarrhea, and collapse; excessive insulin administration, as may occur in pets with diabetes mellitus; insulin-producing tumors of the pancreas, called “insulinomas” or “beta cell tumors”; severe liver disease; some other tumors that produce insulin-like factors; dogs with portosystemic shunts, which are congenital blood vessel abnormalities the cause blood from the intestines to by-pass the liver; hereditary diseases arising from abnormal storage of glucose as starch in the liver, or glycogen storage disease; and serious systemic bacterial infection, or sepsis.

What to Watch For

Signs of low blood sugar in dogs may include: 

  • Loss of appetite
  • Extreme lethargy
  • Incoordination
  • Trembling
  • Muscular twitching
  • Weakness
  • Seizures
  • Unusual behavior
  • Dilated pupils
  • Apparent blindness
  • Stupor or coma
  • Diagnosis of Hypoglycemia in Dogs

    Diagnostic tests are needed to identify hypoglycemia and determine its cause. Tests may include:

  • A complete medical history and physical examination
  • Measurement of blood glucose concentration
  • Other diagnostic blood tests such as complete blood count (also called hemogram or CBC), routine serum biochemistry tests, urinalysis, and serum insulin concentration to try and establish the underlying cause of hypoglycemia.
  • Ultrasound examination of the abdomen to try and identify a pancreatic or other tumor that could be causing hypoglycemia.
  • Treatment of Hypoglycemia in Dogs

    Treatments for hypoglycemia may include the following:

  • Administration of glucose orally or by intravenous injection to increase blood glucose concentration.
  • Treatment for the underlying cause of hypoglycemia
  • Home Care and Prevention

    Administer as directed any medications prescribed by your veterinarian. Observe your dog’s general activity level, appetite and attitude.

    If you have reason to suspect hypoglycemia, you should rub Karo® syrup on your dog’s gums and call your veterinarian immediately. Schedule an appointment with your veterinarian to identify, treat, and monitor the underlying cause of hypoglycemia.

    See your veterinarian for regular check-ups as directly.

    Provide a warm environment, frequent feedings, routine vaccinations and de-worming procedures for puppies as recommended by your veterinarian. Provide frequent, regular feedings. Young puppies should be fed at least 3 to 4 times a day.

    Feed a high quality dog food and provide extra feedings or snacks to working dogs.

    Information In-Depth on Hypoglycemia in Dogs

    Other medical problems can lead to symptoms similar to those encountered in dogs with hypoglycemia. It is important to exclude these conditions before establishing a definite diagnosis:

  • Hepatoencephalopathy, which is abnormal brain function caused by severe liver disease or shunting of blood around the liver
  • Hypocalcemia, or lower than normal blood calcium concentration
  • Central nervous system disorders
  • Spinal cord disorders causing hind limb weakness
  • Syncope (fainting)

    Common causes of hypoglycemia include the following disorders:

  • Addison’s disease, which is an endocrine disorder caused by insufficient hormone production by the adrenal glands
  • Insulin-producing tumors of the pancreas, such as beta cell tumor or insulinoma
  • Glycogen storage disease, which is a hereditary disorders in which enzyme deficiencies cause abnormal storage of glucose in the liver as starch
  • Hunting dog hypoglycemia, which is associated with excessive fasting before strenuous exercise in working dogs
  • Hypopituitarism, a decreased secretion of regulatory hormones from the pituitary gland
  • Insulin overdosage as may occur in pets with diabetes mellitus
  • Juvenile hypoglycemia, which is hypoglycemia in puppies associated with stress, cold, infrequent feeding, and intestinal parasites
  • Laboratory error. Blood glucose concentration can decrease by as much as 10 milligrams per deciliter of blood for every hour the blood is allowed to stand before being processed by the laboratory. Improper sample handling is a common cause of apparent hypoglycemia in blood samples shipped long distances to laboratories. To avoid this error, your veterinarian can use a machine called a centrifuge to spin the blood cells down and separate serum from the blood before shipping the sample to the laboratory for analysis.
  • Liver disease
  • Malabsorption, or impaired intestinal absorption of nutrients
  • Malnutrition. In actuality, prolonged fasting or loss of appetite in otherwise normal adult dogs is not a common cause of hypoglycemia.
  • Tumors of organs other than the pancreas that produce insulin-like substances that can cause hypoglycemia
  • Orally-administered hypoglycemic drugs such as the sulfonylureas, more commonly used to treat diabetes mellitus in some human patients
  • Portosystemic shunt, which is an abnormal blood vessel present at birth that causes blood from the intestines to by-pass the liver
  • Advanced pregnancy rarely can be associated with hypoglycemia
  • Glucose in the urine due to abnormal function of the kidney tubules rarely can be associated with low blood sugar concentration
  • Severe systemic bacterial infection (sepsis)
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