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Name
Hypertrophic Osteodystrophy, Canine
Short Description
Hypertrophic Osteodystrophy (HOD)
AffectedAnimals: Dogs.
Overview: A developmental bone disease usually affecting
puppies between the ages of two and eight months, hypertrophic
osteodystrophy, or HOD, occurs when there is a disturbance in the
blood supply to the growth plate, leading to delays in bone
production. This weakened bony lattice develops microscopic
fractures, with the resulting inflammation causing pain and
lameness. When HOD is severe, the dog may become systemically ill;
loss of appetite, depression, and dehydration are common symptoms.
Courtesy of: Gale Mueller
Note the swollen joints of this great Dane, affected by Hypertrophic
Osteodystrophy.
Fibula
Tibia
Distal Tibia with Enlarged Metaphysis
Calcaneus The breeds most frequently affected by HOD
include the Great Dane, Irish wolfhound, Saint Bernard, Doberman
pinscher, German shepherd, and the weimaraner.
Clinical Signs: Warm, swollen, painful metaphyseal regions of the
long bones, episodic or persistent lameness that is usually
bilaterally symmetric, fever, weight loss, and anorexia.
Symptoms: Pain, swollen limbs, lameness, lack of appetite,
and weight loss.
Description: Hypertrophic osteodystrophy, or HOD, is a disease
usually affecting large breed puppies between the ages of two and
eight months. The disease causes a disturbance in blood supply to
the growth plate, resulting in delays in bone production and
weakening of the bony latticework in this region. Inflammation, cell
death or necrosis, microfractures, and hemorrhage may occur, leading
to pain and swelling of the limbs. All or some of the limbs may show
signs of the disease and the lameness is usually symmetric, meaning
that both the right and left sides of the body are affected equally.
With severe disease, the dog is often systemically ill and may need
supportive care. In the most serious cases, damage to the growth
plates can lead to growth deformities in the limbs. In milder cases,
dogs can make a full recovery with no permanent damage.
Diagnosis: The veterinarian often makes a presumptive
diagnosis if the dog shows signs of the disease and is a commonly
affected breed. A definitive diagnosis is confirmed by taking an
x-ray.
Prognosis: The prognosis is fair to good for mild cases but
guarded for severe cases. Spontaneous regression often occurs in
dogs that reach maturity. In severe cases, growth deformities
requiring surgical correction can result.
Transmission or Cause: The cause is unknown. Viral diseases such as
distemper and other respiratory problems have been thought to play a
role in causing HOD. Vitamin C deficiencies and other metabolic
defects have been suggested as possible causes of HOD, but no
research to date supports this. As some breed lines develop the
disease with increased frequency, a genetic component is suspected.
Treatment: The treatment of HOD is supportive. Intravenous
fluids are given to dogs with a high fever or dehydration. Aspirin,
carprofen, other non-steroidal anti-inflammatory drugs (NSAIDs), or
narcotics may be required to control pain. Calorie-dense diets are
discontinued and the dog is placed on an adult or large breed growth
diet. Also, over-supplementation with vitamins and minerals is
discontinued from the diet, since massive vitamin C supplementation
may contribute to the disease.
Prevention: Avoid feeding high-calorie diets to large or
giant breed dogs. Vitamin and mineral over-supplementation should be
avoided because they may increase the incidence of this disease.
