Diagnosis: Infectious Osteomyelitis


The foal incurred trauma when the dam stepped on its leg, resulting in a puncture in the 
thin skin covering the bone and introduction of bacteria.  Klebsiella spp. are normal flora 
in fecal matter, and were found in the joint tap.  Obvious radiographic changes are not yet 
apparent Ð they only become visible when 30-50% of the bone mineral has been 
absorbed.  This is usually evident 10-14 days after the onset of infection.  Since the 
owner did not report the date of the possible trauma, it can be assumed from the 
radiographs that it was probably a recent occurrence. 

The plasma protein/fibrogen ratio indicates severe inflammation, which is also found in 
cases of infectious osteomyelitis.  The lack of leukocytosis in the lab work is explained 
by the ability of the synovial membrane to contain a significant number of bacteria and 
not permit bacterial proliferation or the subsequent inflammatory response.