Clinical history Usually I select cases in which the radiographic changes are easily identified. However, this month I have selected a patient with minimal radiographic changes. Knowledge of the trauma permits identification of a periosteal response that further directs your attention to the underlying lesion. Good luck. An 11 months old cat presented with a swollen forelimb following a bite wound 3 days earlier. The limb was warm on palpation and painful to the touch. Radiographs were made of the injured limb. Radiographic study Radiographic findings The first glance at the radiographs of the antebrachium of the injured kitten suggests a study with normal bones and joints and with only uniformly dense soft tissue swelling. However, use of the location of the soft tissue swelling makes it possible to focus your attention on the underlying bone. The first glance at the radiographs of the antebrachium of the injured kitten suggests a study with normal bones and joints and with only uniformly dense soft tissue swelling. However, use of the location of the soft tissue swelling makes it possible to focus your attention on the underlying bone. The enlarged view shows the periosteal elevation more clearly and an area of decreased density within the underlying cortex. The second enlargement has small arrows that identify the original level of the outer cortex with the periosteal new bone seen deposited over the cortex. The larger arrows identify the zone of decreased density indicative of the osteomyelitis that is in the center of the periosteal new bone.Comments Usually it is not possible to identify the changes of osteomyelitis this early following trauma. However, in this patient, the young age and the uniform density of the soft tissues make the diagnosis possible. Bone has only a few ways to respond to injury. One of these is through the formation of periosteal new bone. Resulting periosteal elevation is a typical change seen with bone infection and is more quickly identified in the immature patient since the attachment of the periosteum to the underlying cortex is loose resulting in filling of the subperiosteal space with new bone. This can be identified with careful examination of the radiograph.
