Bones consist of two basic components: the cortex and the marrow. The cortex of a bone, which provides its structural support, is composed of calcium and other organic materials. The marrow contains a very rich blood supply, fat and the cells that produce blood. Because bones are highly innervated (rich nerve supply), many diseases of the bones are very painful.

What is Panosteitis?
The word panosteitis can be broken down into “pan,” which means “all” and “osteitis,” which means “inflammation of the bone.” Many synonymous names have been given to the condition; these include eosinophilic panosteitis, enostosis, endosteal proliferation of new bone, juvenile osteomyelitis, wandering lameness, growing pains, pano, and eopan. This condition typically affects the long bones of the limbs and is a painful disease in which the bone marrow becomes very dense. Upon microscopic examination of the affected bones, no inflammation is typically seen (which makes the name panosteitis a misnomer); however, the primary finding is the presence of scar tissue, which subsequently changes into bony tissue. New bone is also formed on the inner (endosteal reaction) and outer surfaces of the bone (periosteal reaction).

The cause of panosteitis is largely unknown. Because the German shepherd breed is commonly afflicted by this condition, genetics may be a factor. Poor diet, stress, infectious diseases, high calcium, high protein and high calorie diets are implicated causes, but no research has substantiated these speculations.

Signs and diagnosis
This condition commonly affects young large breed dogs that are 6 to 18 months of age. Males are more predisposed than females. In females, this condition seems to commonly coincide with the first heat cycle. Breeds of dogs most commonly affected with this condition include great Danes, doberman pinschers, golden retrievers, Labrador retrievers, and basset hounds. Lameness associated with panosteitis is commonly severe, but in some cases is mild. Most dogs have lameness for a period of two to three weeks, but no longer than five weeks on a particular limb. The lameness frequently shifts from one limb to another. Repeated episodes of panosteitis occur until the dog is two years of age. The affected bone is painful upon direct palpation. Fever, tonsillitis, loss of appetite, weight loss and an elevated white blood cell count may also be seen in some cases.

Radiographs (X-rays) of the affected bone will not show any abnormalities early in the course of the disease; however, radiographs are made again in one to two weeks frequently show patchy white densities within the bone marrow cavity, periosteal reaction and endosteal reaction. Within a few months, the appearance of the bone on radiographs returns to normal again.

Panosteitis is a condition that will resolve without any specific treatment; therefore, it has a very good prognosis and rarely causes any permanent side effects to the patient. To keep your companion comfortable, nonsteroidal anti-inflammatory medication and a synthetic narcotic are commonly prescribed. If the pet is not eating and drinking well, intravenous fluids are administered to rehydrate the patient. Rarely, cortisone is needed to help resolve the pain. Exercise should be limited during an acute flare up of the condition; however, if leash walks are well tolerated by the affected pet, this should be encouraged to maintain muscle tone. If your pet’s lameness persists for more than five weeks, a diagnosis of panosteitis is unlikely, and your companion’s veterinarian should make a further investigation into other causes of lameness.

For more information on this subject, speak to the veterinarian who is treating your pet.