Signalment & History
- This patient presents to your clinic for a 10-day history of lethargy, decrease appetite, and lameness in the right thoracic limb. Owners reported a previous left thoracic limb lameness.
- You order Right elbow radiographs.
Findings
- There are multiple ill-defined areas of increased mineral opacity within the medulla of the distal shaft of the humerus, and the proximal shafts of the radius and ulna
- Additionally, there is moderate incongruence of the humerus ulnar joint, with the proximal aspect of the joint being narrower than the distal aspect (green arrows).
Diagnosis
- It is a panosteitis of the humerus, radius and ulna and elbow incongruence with early signs of osteoarthrosis.
References
- Thrall DE. Orthopedic diseases of young and growing dogs and cats. In: Thrall DE, ed. Textbook of veterinary diagnostic radiology. 6th ed. St Louis: Elsevier Health Science, 2013;271.
- UPenn
Canine panosteitis is a disease of the adipose bone marrow and the etiology unknown. It is a spontaneously occurring, self-limiting disease of young, large breed dogs. Although it can affect any part of the diaphysis of long bones, they often originates and are more pronounced near the nutrient foramen. It is characterized by medullary fibrosis (enostosis), as well as by both endosteal and subperiosteal newbone deposition.
The most often affected breeds are the German shepherd, although it has been reported in the basset hound, Chinese Shar-Peis, Giants Schnauzers, Great Pyrenees and Mastiffs. Males are affected more commonly, and the average age at presentation is 5 to 12 months, however, German Shepherd dog can be affected as young as 2 moths and as old as 7 years. Severity and location of radiographic lesions do not necessarily correlate with the severity of clinical signs, and the most clinically affected limb may not have the most pronounced radiographic lesions.
Radiographic signs of Panosteitis
The most common radiographic abnormality is an increased intramedullary radiopacity that may or may not have well-defined margins. The increased opacity is usually hazy, demonstrating either a granular appearance or loss of the normal trabecular bony pattern. The increased medullary opacity usually is not prominent in the area of the nutrient canal of the bone. The earliest radiographic abnormality that may be seen is an increased radiolucency to the medullary portion of bone.
Additional radiographic findings that may be present with or without the medullary density include an endosteal bone thickening and a periosteal reaction. The periosteal new bone is usually smooth or laminar.
