A 15-year-old, mixed breed, male horse was attended with a history of multiple abscesses in the cervical region with a three-year evolution. Upon admission, three fistulous tracts with drainage of purulent secretions in the cervical region, low body score, restriction of cervical movements, and painful sensitivity to palpation were observed. The horse was diagnosed with osteomyelitis secondary to Streptococcus equi infection. The initial treatment was antibiotic therapy and local curative. Owing to the lack of response, surgical debridement was performed. An initial favorable response was observed; however, after 4 months, drainage recurred, and the animal was euthanized. A post-mortem computed tomography scan was performed to obtain details of the injury. Cervical osteomyelitis is rare, and its occurrence through hematogenous spread in adult horses and the tomographic findings had not been reported previously. The long period of evolution, difficulty in performing an aggressive debridement, and the presence of multi-drug resistant bacteria contributed to the negative outcome. RESUMOUm equino macho, sem raça definida, de 15 anos de idade, foi atendido com histórico de múltiplos abscessos cervicais com evolução de três anos. Na admissão, foram observados: três trajetos fistulosos com drenagem de material purulento na região cervical; baixo escore corporal; restrição de movimentos cervicais; e sensibilidade dolorosa à palpação da região. Foi diagnosticada osteomielite vertebral cervical secundária à infecção por Streptococcus equi. O tratamento inicial consistiu na administração de antibióticos e curativo local. Na ausência de resposta à terapia, realizou-se o debridamento cirúrgico. Inicialmente, obteve-se uma resposta favorável, entretanto, após quatro meses, houve recidiva da lesão e o animal foi submetido à eutanásia. Realizou-se tomografia computadorizada no post mortem para detalhamento da lesão. A osteomielite vertebral cervical é rara, e sua ocorrência por meio de disseminação hematógena em animais adultos não foi previamente reportada. O longo período de evolução, aliado à dificuldade de realização de um debridamento agressivo, e a característica multirresistente do agente etiológico contribuíram para o desfecho negativo do caso. Palavras-chave: tomografia, infecção óssea, debridamento cirúrgico

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Medical management of abdominal abscesses in horses requires prolonged antibiotic therapy and presents varied success rates. A 6-year-old male horse with a history of colic and multiple abdominal punctures to relieve gas was attended. At admission, tachycardia, tachypnea, hyperthermia, mucosal congestion, dehydration, and rigid gait were observed. The association of physical examination, laboratory and ultrasonographic findings allowed the diagnoses of peritonitis and abdominal abscess. Supporting treatment plus broad spectrum antibiotic therapy was performed: daily intraperitoneal ceftriaxone (25 mg/kg, 7 days); daily intravenous gentamicin (6.6 mg/kg, 7 days); per os metronidazole three times a day (15 mg/kg 12 days), followed by the same dose twice a day (15 mg/kg 33 days), totaling 45 days of treatment. Plasma fibrinogen and ultrasonographic examination were the most effective tools to evaluate abscess evolution. There was normalization of the physical examination 24 h after beginning the treatment, consecutive regression of the nucleated cell count in the peritoneal fluid, and regression of plasma fibrinogen and size of the abscess. On the 10th treatment day, the animal was discharged from the hospital, maintaining oral therapy with metronidazole every 12 h (15 mg / kg). When the animal returned on the 30th day, an abscess size regression was observed. However, there was no resolution, and therapy with metronidazole was maintained. On the 45th day of treatment, a new hospital evaluation was performed, where the abscess resolved, and metronidazole was suspended. It is highlighted that the therapeutic association used in the treatment of abdominal infection and abscess resulted in a rapid clinical response