Clinical history A zebra foal 21 days old was presented with generalized lameness with swelling of multiple joints. He had been on antibiotic therapy for 1 week prior to presentation. A skeletal radiographic survey was made Left metacarpophalangeal joint Right metacarpophalangeal jointRight/left stifleWhat are the radiographic changes noted
- The major changes are lesions characterized with bone lysis with a rather sharp margin
- The lesions in the physes expand into adjacent epiphyses and metaphyses
- The apophyseal lesions are focal
- Because the lesions are hematogenous they are polyostotic
- Soft tissue swelling may be due to capsular distention
What are the radiographic changes noted Hematogenous osteomyelitis Joint tap Multiple joints were tapped with purulent fluid noted from all joints. A total of 170,000 cells were present with mild degeneration of neutrophils. No bacteria were cultured. Comments Osteomyelitis in horses can be divided into 3 categories, based on the origin of the infection - hematogenous, traumatic, and iatrogenic - hematogenous origin occurs primarily in neonates - infection in foals can be divided into 3 categories based on the location of the lesions - S-type involves the synovial membrance of joints, P-type involves the physis and usually the metaphysis, and Etype involves the epiphysis. Lesions in the apophyses deserve a separate location - such as A-type. The primary infection in the foal is frequently the umbilicus, GI tract, and lungs - foals with a compromised immune system may result from failure of passive transfer or septicemia. This foal had “dripping” from the umbilicus suggesting an omphalophebitis (“navel ill”).
