DIAGNOSIS:
		Septic Arthritis:  

Pathophysiology; Septic arthritis is due to bacterial colonization of areas in the growth 
plate and synovial membrane, where blood flow is sluggish.  Bacteria can originate from 
the umbilicus or the respiratory tract, and could include Strep, Salmonella, and E. coli, 
among others; in our case, we found Klebsiella pneumoniae, which suggests respiratory 
origin (septic arthritis often will develop in a foal previously treated for pneumonia).  
Infection of the joint may result in bacterial accumulation in the joint and poor drainage 
of the resulting exudate.  Joint cartilage is destroyed due to proteolytic enzymes released 
from white blood cells, resulting in acute lameness.  Since the onset of lameness is often 
abrupt, owners may believe that the animal has been kicked or has suffered some other 
trauma, as in this case.