Case reveal

Findings

Centered on the stifle joint, there is severe thickening of the soft tissues, predominantly in the region of the femoropatellar joint. The patella is subsequently cranially displaced. Within the patella, there are irregularly marginated and radiolucent regions . Additionally, there is irregularly margination along the proximal aspect of the patella. In the cranial aspect of the distal femoral epiphysis adjacent to the physis, a focal region of decreased mineral opacity is noted. The trochlear ridges of the femoral epiphysis are also irregularly marginated.

Diagnosis

Severe left stifle joint effusion with aggressive lesions within the femur centered on the distal femoral physis. This is consistent with septic arthritis, physitis, and epiphysitis with patellar involvement.

A little bit more…

Septic arthritis in foals

• Etiology
  • Decreased ingestion of adequate maternal antibodies from colostrum
    • Mare: leaked colostrum before parturition
    • Foal: delayed suckling
• Presentation
  • Usually less than 1 month of age
    • Younger neonates (birth to 36 hours): joint effusion as sign of septicemia
    • Older neonates (> 36 hours): appear normal at first then develop lameness over days or weeks
  • Clinical signs
    • Signs of pressure over joint (thickened or leather-like skin over boney prominences)
    • Decubital ulcers (secondary to orthopedic pain)
    • Recumbency

• Pathophysiology
  • All joints and growth plates have the potential for hematogenous infection, the joints of the axial skeleton are affected most often
    • Tarsal, stifle, metacarpo-/tarsophalangeal, and carpal joints are more frequently affected
  • Septic physitis may not present with joint swelling, but rather with edema over the growth-plate region
• Diagnostics
  • Radiographs may not detect early stages of disease process

References

Paradis, MR. Septic arthritis in foals. DVM360 Magazine. 2005