What is panosteitis?
Panosteitis is a painful inflammation of the outer surface or shaft of one or more long bones of the legs. It is sometimes called growing pains. Panosteitis may occur in more than one bone at a time or may move around, causing a shifting lameness that goes from one bone or leg to another. The lameness tends to occur very suddenly, spontaneously, and without a history of trauma or excessive exercise.
Are all dogs affected by this condition?
Panosteitis is a condition that affects young, rapidly growing dogs. Although it can occur in any breed of dog, larger breeds are more prone to this problem (e.g., German shepherd (most common), Great Dane, golden retriever, Labrador retriever, rottweiler, Doberman pinscher, and basset hound).
Affected dogs are usually between 6 and 18 months of age, but the first symptoms may occur as early as 2 months of age. Males seem to be affected more often than females, although either sex can develop panosteitis. Affected dogs often have recurrent episodes of panosteitis until they reach 2-2.5 years of age, at which time it will spontaneously resolve. Dogs as old as 5 years of age, however, have been diagnosed with the condition.
What is the cause?
Panosteitis is a painful condition, and the pain is likely caused by increased pressure within the bone and/or stimulation of pain receptors in the periosteum (the outer, soft tissue lining of the bone). The underlying cause of panosteitis is unknown, but genetics, stress, infection, metabolism, or nutrition may be factors. Since German shepherds seem particularly predisposed to panosteitis, there may be a genetic component to the disease, at least in this breed.
What are the clinical signs?
The typical symptom is a sudden, unexplained, painful lameness of one or more legs. The lameness may be mild or severe. The most common bone affected is the humerus (upper arm), but panosteitis may also be found in the radius and ulna (both bones in the foreleg), the femur (thigh) and/or the tibia (lower rear leg). The affected bone will be painful to the touch. You may also notice other symptoms, such as fever, not eating, tiredness, or weight loss.
Panosteitis tends to be cyclical, with periods of worsening symptoms followed by periods of improvement. The pain often shifts from leg to leg. Each episode of lameness may last for a few days to weeks. The period between episodes is often about a month, but may vary.
How is it diagnosed?
Your veterinarian will suspect panosteitis if the dog shows pain when pressure is applied to the affected bone(s). The diagnosis is confirmed by X-rays (radiographs), which usually show a characteristic increase in the density of the affected bones. The degree of change may not correspond to the severity of the lameness. In some cases, radiographic evidence may not be present for up to 10 days after lameness begins; in these cases, repeated X-rays taken 2 weeks later will confirm the diagnosis. After the condition has resolved, the bone density normalizes and the bone looks normal on X-rays.
Your veterinarian may also recommend blood tests, particularly a complete blood count (CBC), to look for signs of systemic inflammation that might support this diagnosis.
What is the treatment?
Although this disease is self-limiting, and will spontaneously resolve, the condition is very painful during episodes of lameness. At these times, treatment is supportive, using pain medications (analgesics) and/or anti-inflammatory drugs (e.g., meloxicam, brand name Metacam®) as needed. Sometimes, some dogs may respond better to one anti-inflammatory than another, so trying a different drug may be helpful if they still seem in pain.
"Pain control should always be given to help your pet feel more comfortable; denying your dog pain control is inhumane."
Pain control should always be given to help your pet feel more comfortable; denying your dog pain control is inhumane.
During episodes of lameness, exercise should be restricted. Between episodes, light to moderate exercise should be encouraged, but hard or vigorous exercise is discouraged, as are very long walks.
Some dogs with panosteitis have a poor appetite; in these cases, it is important to ensure they are given a properly balanced and appetizing diet. In some cases, supplements such as nutraceuticals, omega-3 fatty acids, or antioxidants may be helpful.
What is the prognosis?
Panosteitis is a self-limiting disease, meaning that it will eventually go away. The disease should be completely resolved by the time the dog reaches 18-24 months of age. Each episode of lameness should last no longer than 3 weeks. If your pet's lameness persists without relief for longer than 4-5 weeks, it is likely that the dog is affected by another bone disorder (see handout on “Bone Diseases of Growing Dogs” for further information).
If panosteitis is a self-limiting disease, why is it necessary to perform diagnostic procedures such as X-rays?
Although panosteitis is not a serious disease, and is a common cause of lameness, other, more serious bone diseases can also cause lameness in young dogs. X-rays are necessary to be sure that a sudden onset of lameness is not caused by one of these more serious bone diseases. If they show the typical lesions of panosteitis, then you can rest assured that your dog will eventually outgrow the problem.
Are there any preventive measures I can take to prevent panosteitis in my large breed dog?
There are potential links between panosteitis and diets containing excessive levels of dietary protein and/or calcium. For that reason, you may be tempted to feed your large-breed puppy with adult dog food, which contains lower levels of protein and calcium. However, this is not advised, because adult dog food has lower calories (energy levels) than puppy food. Rapidly growing puppies require high levels of dietary energy to grow, and will need to eat more of a low-energy food to meet these requirements. Eating more of a low-energy diet will result in a higher overall intake of protein and calcium.
A better option is to feed an affected dog a high-quality diet that has been specifically formulated for large breed puppies or adolescents, and to restrict the quantity fed to keep the dog at a lean, healthy body weight. Do not allow your puppy to become overweight. Consult your veterinarian for further advice on the most appropriate nutrition for your dog.