Hypoglycemia is a sudden fall in the concentration of glucose in the blood below normal levels. The body uses glucose as its primary energy source. The brain, for example, is completely dependent upon glucose to function. The liver is responsible for manufacturing glucose and for storing it in a usable form for release into the blood stream as needed. Muscle tissues store some of the important materials used in this process.
Hypoglycemia Must Be Treated
Transient juvenile hypoglycemia, which is brought on by fasting, is common in toy dog breeds, such as Yorkshire Terrier, Toy Poodle, and Pomeranian. It is usually seen in puppies 5 to 16 weeks of age. Stress, low body temperature, poor nutrition, sudden change in feed, water and schedule patterns, infections, and premature birth may precipitate the onset of hypoglycemia. Some puppies, bred exclusively for tiny size ("teacup Yorkies", "teacup Chihuahua"), are even more predisposed to transient juvenile hypoglycemia since insufficient muscle mass may make it difficult for the body to store the glucose and keep its blood sugar properly regulated.
Most common clinical signs of hypoglycemia are drowsiness, shivering, collapsing, disorientation, seizures, listlessness, depression, muscle weakness and tremors. Lee Weston, author of the article about hypoglycemia (Pomeranian Club of Canada) says that "the entire sequence of clinical signs is not always seen, so close observation of your pet and knowing when your dog is going into a distressed state can mean the difference between life and death of your dog. Immediate treatment by a veterinarian is imperative, as recurrence of, or prolonged attacks, can cause permanent damage to the brain."
It has been proven experimentally that eight hours fasting in a Yorkshire Terrier puppy can result in marked variation of blood glucose, showing both hypo- and hyperglycemia. Frequent feeding of a high-energy, protein-rich diet to both mother and puppies may prevent toy-breed puppies from developing hypoglycemia and may help them to overcome periods with a decreased intake of energy.
Puppies and dogs can develop severe hypoglycemia after consuming sugar-free gum sweetened with the sugar-alcohol xylitol. In humans, xylitol has little to no effect on plasma insulin or glucose levels, but in dogs xylitol is a strong promoter of insulin release and can cause severe hypoglycemia with collapse and seizures. With the increased appearance of xylitol-sweetened products, xylitol toxicosis in dogs may become more common. Sometimes, a dog will outgrow this condition.
Hypoglycemia In Adult Dogs And Cats
A common cause of hypoglycemia in dogs is a functional islet cell tumor of the pancreas (insulinoma). While a wide variety of breeds may be affected, the Labrador Retriever, German Shepherd Dog, Irish Setter, Standard Poodle, Collie, Boxer, Fox Terrier, and most Toy breeds may have a higher incidence than other breeds. Insulinomas occur less frequently in cats.
Hypoglycemia can result from excessive insulin administration to animals with diabetes mellitus, and cats may be at greater risk of insulin overdose than dogs, especially if the cats are obese and receiving insulin doses > 6 U/injection, administered once or twice daily. Hypoglycemia in highly nervous hunting dogs is also well recognized. Attacks are characterized by apparent disorientation, weakness and generalized seizures. Although recovery is rapid, the affected animal's hunting ability may be compromised. Frequent feedings with protein-rich foods and candy bars may prevent the attacks. The cause has not been determined. In adult dogs, hypoglycemia may also occur with severe Addison's disease, liver disease, sepsis, and a complication of pregnancy accompanied by ketonuria, a dangerous feature of severe and uncontrolled diabetes.