Dog Labrador Retriever 4 months of age Presented with a history of fever of unknown origin and painful and swollen multiple joints. Radiographs of the thorax and abdominal ultrasound were within normal limits. Radiographs of the right antebrachium were taken. Radiographic examination Mediolateral and craniocaudal view of the right distal front limb Radiographic findings
- There is a moderate soft tissue swelling centred on the right carpus mainly dorsal (arrow).
- There are radiolucent linear areas in the metaphysis of the radius and ulna (empty arrows) oriented parallel to the physis. The metaphyseal bone has a subjective increased radioopacity.
- Similar changes are present in the proximal metaphysis of the radius and distal metacarpus II(arrowheads).
- There are ill defined and cloudy linear mineral opacity dorsal to the proximal and distal metaphysis of the radius.
- The radiographic signs are pathognomonic for hypertrophyc osteodystrophy.
Radiographic findings Mediolateral (left), craniocaudal (middle) and its close up (right) of the right distal limb. Radiographic findings Considering that the disease has a systemic distribution, radiographs of the contralateral side and both the tarsal region were taken. Similar radiographic signs were present in the left distal front limb and both distal tibia . Mediolateral view of the left and right tarsus Comments
- Hypertrophic osteodystrophy (HOD) is a systemic illness that usually affects large- and giant breed dog between the age of 2 and 7 months.
- The bone lesions are usually bilaterally symmetrical and involve the metaphysis of long bones, particularly the distal radius, ulna and tibia.
- Early radiographic signs include transversely oriented lucent zones within the metaphysis that are parallel and adjacent to the physis (‚double physis‘ sign). A thin margin of subchondral bone sclerosis may parallel the lucent zone and is caused by collpse of the necrotic trabecular bone.
- With time, irregular periosteal new bone formation forms around the metaphysis and is usually distinct and separate from the cortex in the earlier stage of the disease.
- Diffuse soft tissue swelling can be seen centered on the metaphyeal regions.
