Diagnosis: Infectious Arthritis

The specialty exam results, in conjunction with the clinical signs, support a diagnosis of 
infectious arthritis due to Klebsiella pneumoniae. The synovial fluid analysis indicates 
that this infection is still its early stages, given the low presence of mononuclear cells and 
the good mucin clot. The CBC also shows no leukocytosis, further suggesting that this 
infection is relatively new.

Trauma and infectious arthritis are the top two differentials for foals under 45 days of 
age. Although the client had thought that the foalÕs problem may have stemmed from 
trauma caused by the mare, the more likely explanation is that this is a case of joint-ill 
stemming from the hematogenous spread of Klebsiella.