Hypertrophic Osteodystrophy (HOD) in Dogs

Overview of Canine Hypertrophic Osteodystrophy (HOD)

Hypertrophic osteodystrophy, also referred to as HOD, is an orthopedic disease seen in immature large and giant breed dogs. The cause of HOD is unknown, but it may be linked to diet or an infectious disease. HOD goes by other names including skeletal scurvy, osteodystrophy II, idiopathic osteodystrophy, metaphyseal osteopathy and Moller-Barlow’s disease.

Hypertrophic osteodystrophy causes inflammation of the growing bone leading to pain and lameness. HOD primarily affects the front legs but can also affect the rear legs, scapulae and ribs of young growing dogs often starting at 2 months of age to 8 months of age.

Breeds most commonly affected include the Great Dane, Irish wolfhound, Saint Bernard, borzoi, boxer, Dalmatian, Irish setter, Weimaraner, German short-haired pointer, Doberman pinscher, German shepherd, Labrador retriever, Collie, greyhound, basset hound and some terriers. Signs usually develop between two and eight months of age.

What to Watch For

• A slight limp or a severe lameness such that the animal holds the limb up
• Swollen and painful carpus (wrist area), which may also be warm to touch
• Reluctance to move
• Fever (to 106 degrees F.)
• Lethargy
• Depression
• Lack of appetite (anorexia)
• Weight loss

Diagnosis of Hypertrophic Osteodystrophy (HOD) in Dogs

• Your veterinarian will ask you many questions in order to develop a complete history of the course of the disease. These questions may include: When did the problem start? Which limb or limbs are affected? Have you treated the dog with any medication? What sort of response did the medication bring about?
• Your veterinarian will also examine your dog completely to determine the source of the lameness and to check for a fever.
• X-rays (radiographs) of the legs are taken to see the typical changes associated with HOD and confirm the diagnosis.

Treatment of Hypertrophic Osteodystrophy (HOD) in Dogs

Treatment includes the administration of pain relievers, such as deracoxib, aspirin, carprofen, or etodolac. If the dog is severely debilitated, he may require hospitalization and intravenous fluid therapy and/or nutritional support.

Home Care and Prevention

Be aware of your pet’s normal gait, appetite, and demeanor so that you can be aware of any changes. Contact your veterinarian if you notice any of the above signs of hypertrophic osteodystrophy.

If you own a large or giant breed of dog, feeding a puppy food that is labeled for large- or giant-breed dogs may help prevent this and other orthopedic conditions.

In-Depth Information on Hypertrophic Osteodystrophy (HOD)

Hypertrophic osteodystrophy (HOD) is a disease of young, skeletally immature large- and giant-breed dogs. The cause of HOD is unknown. An old theory was vitamin C deficiency, but this theory has since been discarded. Currently, excessive nutritional supplementation, genetics, and possibly an infectious agent are believed to play roles in the development of HOD. HOD develops in puppies between two and eight months of age, more commonly around three to four months of age.

Dogs with HOD have a limp that can be mild or so severe that they hold the leg off of the ground. The front legs are usually affected, and both front legs are often affected at the same time. The disease can be episodic, such that the signs come and go.

The carpi or wrists are usually swollen, painful, and warm to the touch. Affected pups usually have a fever, are not interested in food, and are depressed and lethargic.

This disease can present with signs similar to other orthopedic diseases of young dogs, such as panosteitis or osteochondrosis. Panosteitis is an inflammatory condition of the long bones of young large breed dogs. Osteochondrosis is an abnormality of mineralization of the bones of young growing dogs, which can result in disruption of joint cartilage overlying the bone.

In-depth Information on Diagnosis

History and physical examination are important in any illness. Your veterinarian will perform a complete physical exam, examining all four legs carefully. Often, orthopedic disease can affect more than one leg, but the dog will only be obviously lame on the worst leg. Your veterinarian will also take your dog’s temperature to check for a fever. Specific tests may include:

• Radiographs (X-rays). After determining which legs or joints are painful, your veterinarian will take radiographs of the affected leg and may also take radiographs of the opposite leg both for comparison and also because many of these orthopedic diseases affect the same area on the opposite leg. HOD has a typical radiographic appearance of the radius and ulna bones of the forelimb in the area near the carpus (wrist). Radiographs are taken to confirm the diagnosis of HOD.
• Blood tests. If your dog is severely debilitated, your veterinarian may submit blood tests to check your dog’s hydration status and electrolyte levels.

In-depth Information on Treatment

Since the cause for this disease is unknown, specific treatments for it are not available. The disease is usually self-limiting and runs its course as the dog matures. The treatments are therefore designed to make the dog comfortable and keep him nourished through the disease.

• Therapy is usually supportive care. Pain is relieved by giving nonsteroidal anti-inflammatory drugs, such as deracoxib, aspirin, carprofen (Rimadyl®), or etodolac (Etogesic®). These drugs can have side effects on the stomach, kidneys, and liver, so they should only be used under the direct supervision of a veterinarian.
• If the dog is severely debilitated and dehydrated, hospitalization may be required. Your veterinarian may administer intravenous fluids to your dog and possibly institute nutritional supplementation, in order to keep him hydrated and well nourished.

Prognosis with Hypertrophic Osteodystrophy (HOD)

Dogs that are mildly affected have a very good prognosis, but dogs that are severely affected have a guarded prognosis and may be euthanized because of unrelenting pain or poor nutritional status.

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not rapidly improve.

• Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your dog.
• Be familiar with your pet’s gait, appetite, attitude and activity level. It can be very helpful if you notice subtle changes in your pet’s gait or behavior. The more you are aware of what is “normal” for your pet, the quicker you will be able to pick up on something going wrong. As with most diseases, early detection and intervention is best.
• Be familiar with your dog’s body. If you notice any swelling of the joints or bones, contact your veterinarian.
• If the adjacent growth plates, the part of the bone responsible for elongation, are also affected, they may close prematurely and cause abnormal growth of the bones. The bone will grow curved or crooked. If your dog was diagnosed with HOD, watch the growth of his legs carefully over following weeks to months. If you notice any curve or crooked shape, you should notify your veterinarian right away. Your dog will likely need surgery to correct the crooked bone.

Follow-up Care for Dogs with Hypertrophic Osteodystrophy

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your pet does not rapidly improve.

• Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your pet.
• Be familiar with your dog’s gait, appetite, attitude and activity level. It can be very helpful if you notice subtle changes in your pet’s gait or behavior. The more you are aware of what is “normal” for your pet, the quicker you will be able to pick up on something going wrong. As with most diseases, early detection and intervention is best.
• Be familiar with your dog’s body. If you notice any swelling of the joints or bones, contact your veterinarian.
• If the adjacent growth plates, the part of the bone responsible for elongation, are also affected, they may close prematurely and cause abnormal growth of the bones. The bone will grow curved or crooked. If your dog was diagnosed with HOD, watch the growth of his legs carefully over following weeks to months. If you notice any curve or crooked shape, you should notify your veterinarian right away. Your dog will likely need surgery to correct the crooked bone.