Bacterial meningitis and brain abscesses secondary to infectious disease processes involving the head in horses: seven cases (1980-2001)

OBJECTIVE: To determine clinical features of horses with bacterial meningitis or brain abscesses secondary to infectious disease processes involving the head. DESIGN: Retrospective study. ANIMALS: 7 adult horses. PROCEDURE: Medical records of Tufts University, the University of Pennsylvania, and the Livestock Disease Diagnostic Center (Lexington, Ky) were reviewed to identify adult (> 12 months old) horses in which a postmortem diagnosis of bacterial meningitis or brain abscess had been made. Horses were included in the study if an intracranial infection was confirmed, the horse had a primary infectious disease process involving the head, and there were no signs of systemic infection. RESULTS: 23 adult horses with bacterial meningitis or a brain abscess were examined during the study period, but only 7 met the criteria for inclusion in the study. Primary sites of infection included the paranasal sinuses, nasal cavity, periocular tissues, and submandibular lymph nodes. Three horses died suddenly prior to hospitalization, and 1 horse was hospitalized but died 7 days after the onset of neurologic abnormalities. The remaining 3 horses were euthanatized because of a rapid deterioration in clinical status. CONCLUSIONS AND CLINICAL RELEVANCE: Although rare, fatal intracranial complications can develop in horses with infectious diseases involving the head.