21-Day-Old Dutch Warmblood Colt

Signalment & History

  • This patient presents for an acute onset of severe left hind limb lameness three days prior after apparently falling down in the mud.
  • Prior history includes mild dystocia and possible partial failure of passive transfer.
  • On physical examination, his vitals are normal. There is palpable stifle effusion within the left joint and thickening of the muscle of the caudal thigh.

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There is a severe amount of soft tissue swelling within the stifle joint, mostly localized within the femoropatellar joint. This is causing cranial displacement of the patella. There are irregularly marginated, radiolucent regions within the patella. Additionally, there is irregularly margination along the proximal aspect of the patella. There is a focal region of decreased mineral opacity in the cranial aspect of the distal femoral epiphysis adjacent to the physis. There is also irregular margination within the trochlear ridges of the femoral epiphysis.


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


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


Paradis, MR. Septic arthritis in foals. DVM360 Magazine. 2005 http://veterinarynews.dvm360.com/septic-arthritis-foals?rel=canonical