Key Points

Lameness usually lasts 2 to 3 weeks, but not longer than 5 weeks; therefore if your pet’s lameness has been going on for longer than 5 weeks, your pet likely has another condition

The lameness may shift from one limb to another

This disease is treated with pain medications

This disease usually does not recur after 12 to 18 months of age

Signalment

• Young large breed dogs that are 6 to 18 months old
• Common breeds affected
  • German Shepherds (most common)
  • Great Danes
  • Doberman Pinscher
  • Golden retriever
  • Labrador retriever
  • Basset hounds

Synonyms

• Eosinophilic panosteitis
• Enostosis
• Endosteal proliferation of new bone
• Eopan

Clinical Presentation

• Affects the shaft of long bones
  • Top of the ulna (front limb)
  • Lower part of humerus bone (front limb)
  • Central radius bone (front limb)
  • Central femur bone (thigh bone)
  • Upper end of tibia bone (hind limb)
• Lameness is frequently of sudden onset
  • May be mild to severe
  • Lameness usually lasts 2 to 3 weeks, but not longer than 5 weeks; therefore if your pet’s lameness has been going on from a solid period of time that is greater than 5 weeks, your pet likely has another condition
  • The lameness may have a recurrent pattern
  • The lameness may shift from one limb to another
• The affected bone is painful to touch
• Some dogs can show signs of
  • Fever
  • Tonsillitis
  • Elevated white blood cell count

Radiograph

Signs on Radiographs (x-rays)

• If the disease is early in its course no abnormalities may not be seen on the radiographs; if the radiographs are repeated in 2 weeks the problem usually can be seen
• Increased density in the marrow cavity of the affected bone can be seen
• The wall of the bone becomes thicker due to new bone formation on the inner and outer layer of the bone
• Two to three months later the bone normalizes and the bone looks normal on radiographs again
• In the radiograph take note of the lighter spots in the marrow cavity (denoted by the arrows) which is eopan
• In the CT scan Panosteitis is a blotchy density within the bone marrow cavity

CT scan

Microscopic Signs

• There usually is no inflammatory component of panosteitis
• The main change seen is fibrosis of the marrow (scar tissue develops)
• With time the fibrous tissue changes into bone, hence the increased density as seen on the radiographs
• New bone formation on the inner and outer part of the bone can be seen

Cause

• Unknown
• Potentially an unidentified viral infection

Treatment

• Self-limiting disease that has a spontaneous recovery
• Repeated bouts of this disease are about one month apart
• Problem usually does not recur after 12 to 18 months of age
• Treatment is supportive
• Anti-inflammatory medications
• If the pet is systemically ill, then intravenous fluid therapy may be needed for rehydration