HYPOGLYCEMIA
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 hypoglycemia. Toy breed dogs of any 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.

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 hypoglycemia. Toy breed dogs of any 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.