Causes of Pituitary Dwarfism in Dogs
Canine pituitary dwarfism syndrome is often inherited. Breeds prone to the syndrome include the German Shepherd and the Carnelian bear dog. The trait exists on a recessive gene, so an affected puppy must have inherited one deformed gene from each parent. When two of these defective genes appear in the same puppy, pituitary dwarfism occurs.
Pituitary dwarfism in dogs can also occur when the pituitary gland fails to develop normally. Cysts, tumors and other growths in the pituitary gland can also cause underproduction of growth hormone.
Symptoms of Pituitary Dwarfism in Dogs
Dogs with pituitary dwarfism syndrome appear perfectly normal when they're born. However, by the time they're two or three months old, it's become evident that they're not growing at the same rate as their peers. Dogs with pituitary dwarfism syndrome have proportionate limbs and a proportionate torso (unlike dogs with skeletal dwarfism, which causes abnormalities in proportion). These dogs don't appear deformed or abnormal in any way; they're just small.
If your dog is suffering from pituitary dwarfism, he'll remain smaller than the other puppies in his litter. He'll retain his soft, woolly puppy coat, but may eventually develop hair loss, or alopecia. He may suffer from hyperpigmentation, or abnormal darkening of the skin. His permanent teeth may come in late, or may never come in at all.
Dogs with pituitary dwarfism syndrome are often sterile. Females may never come into heat, and males may have small testicles or undescended testicles throughout their lives.
Diagnosing Canine Pituitary Dwarfism
Your vet will need to run a number of diagnostic tests, including blood tests, urinalysis and biochemical profiles to ensure that your dog isn't suffering from secondary conditions. Your vet will test levels of growth hormone in your dog's blood to verify the presence of canine pituitary dwarfism syndrome. Your vet will also want to check levels of your dog's other normal hormones, to ensure that further endocrine problems haven't occurred. Problems with the thyroid and adrenal glands, which also make up the endocrine system, are common in dogs with reduce pituitary function.
Treating Pituitary Dwarfism Syndrome in Dogs
Your dog will need many injections of growth hormone, given several times a week for some months. He may need thyroid hormone replacement therapy if the thyroid gland has ceased to function or is functioning improperly. Cortisone replacement therapy may be in order if your dog's adrenal gland has been compromised.
Once your dog reaches sexual maturity, you'll be advised to neuter him. Pituitary dwarfism syndrome in dogs is usually hereditary and dogs who suffer from pituitary dwarfism syndrome should not be bred.