Just like people dogs need to have sugar in their blood to supply the body and brain with the fuel it needs to work properly and efficiently. In some breeds, particularly the toy dogs such as Chihuahuas, Yorkshire Terriers, Pomeranians and Maltese hypoglycemia can be a problem in adult dogs that simply don't have enough body fat to carry their blood sugar between meals. Most of these small breeds have a significant drop in blood sugar that can trigger hypoglycemia if fasting for more than eight hours.
Another type of hypoglycemia is called juvenile hypoglycemia that occurs when puppies are weaned and switched to regular dog foods. Often these puppies do not eat properly or skip meals, leading to rapid drops in blood sugar resulting in seizures, lethargy and poor growth and development. The smaller breed puppies, especially those that are bred to be teacup or toy are most prone to the problem, but any puppy that is not getting proper nutrition can develop the symptoms. [...]