What Is Your Diagnosis?

The research article focuses on the diagnosis and treatment of a three-year-old British Warmblood gelding, who was found to have severe lameness in the rear left limb of unknown cause which worsened over 24-48 hours. Diagnostic imaging and clinical pathology revealed inflammation, infection, trauma and possible fracture in the horse’s foot which led to euthanasia due to the severity of the conditions.

Case History and Initial Examination

• The horse under study, a three-year-old gelding, was presented with severe lameness in its rear left limb.
• On examination, swelling and a small puncture wound were identified on the left hind limb.
• An ultrasonographic exam revealed serious inflammation within the tendon sheath and increased echogenicity within the synovial fluid.
• Clinicopathologic analysis of the collected synovial fluid showed higher than normal white blood cell count, total protein concentration, and lactate concentration, suggesting infection or inflammation.

Diagnostic Imaging Findings and Interpretation

• Radiographic and MRI examination of the affected limb revealed a sclerotic osteochondral fragment within the second phalanx bone.
• Other abnormalities were detected, including extracapsular soft tissue swelling around the proximal interphalangeal joint and lesions of various intensities within the subchondral bone.
• Based on these findings, the primary diagnoses included fracture, sequestrum, separate center of ossification, or osteochondrosis.
• In addition, the possibility of trauma with a subsequent sequestrum and involucrum formation, osteomyelitis, or a large, devitalized osteochondritis-like fragment was considered.

Treatment and Outcome

• Arthrocentesis was performed on the proximal interphalangeal joint, and the collected fluid was tested, showing similar signs of infection or inflammation as the previously collected synovial fluid.
• However, bacterial cultures did not yield any growth, making it difficult to identify the source of the infection.
• Due to the extensive damage to articular and bone tissues, along with the inability to identify the cause of infection, the horse was deemed to have a poor prognosis.
• With the owner’s consent, the gelding was euthanized.

Postmortem Findings

• Postmortem MRI and CT scans confirmed antemortem findings and further indicated a bone sequestrum at the proximal articular surface of the second phalanx.
• Necropsy findings, including edema of the skin and subcutaneous tissues, were consistent with synovial sepsis in both the tendon sheath and the PIJ.
• The necropsy also revealed signs of a possibly unwitnessed traumatic event, exacerbating the conditions leading to the horse’s lameness.