Surgical management of Rhodococcus equi metaphysitis in a foal.

The research article discusses a case where a young horse experienced long-term lameness due to chronic Rhodococcus equi metaphysitis in its left third metatarsal bone, which was treated through a combination of erythromycin estolate and rifampin, surgical debridement, and cancellous bone grafting.

Rhodococcus equi metaphysitis

• The study revolves around a young foal suffering from a chronic condition known as Rhodococcus equi metaphysitis. This condition involves a bacterium, Rhodococcus equi, attempting to infect the metaphysis, or growing section of a long bone. In this particular case, it affected the distal growth plate of the left third metatarsal bone in the foal.

Evident Symptoms

• The bacteria’s activity led to the foal’s longstanding lameness, an issue often associated with a difficulty or abnormality in movement.
• The horse was also suffering from several abnormal hematologic values including mild anemia, hyperfibrinogemia (an excess of fibrinogen in the blood), mild leukocytosis, and neutrophilia (an increase in neutrophil count).

Diagnosis

• Radiography, a common diagnostic tool in veterinary medicine, was used to visualize the distal part of the foal’s MT3 bone. The results revealed a radiolucent zone on the medial aspect of the growth plate, indicating an area of bone loss or destruction.
• Small pieces of dead bone tissue, known as sequestra, were also identified in the radiographic images.

Treatment and Management

• The researchers treated the foal’s infection using a combination of two antibiotics – erythromycin estolate and rifampin – known for their efficacy against Rhodococcus equi.
• Aggressive surgical debridement, a procedure to remove damaged or infected tissue, was also performed to limit the spread of the infection and to promote healing.
• Cancellous bone grafting, a procedure that uses spongy bone to promote new bone growth, was performed to assist in the recovery of the damaged bone.

Outcome

• Following the combined surgical and medical treatment, the infection in the bone was successfully resolved, suggesting a viable approach to similar cases in the future.