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)
