Histopathological evidence of septic emboli within the cerebral vasculature in a dog with streptococcal meningoencephalomyelitis

Abstract A 2‐year‐old, female, neutered, crossbreed dog presented with acute lethargy, pyrexia and paraparesis that rapidly progressed to paraplegia with loss of nociception and stuporous mentation. Neurological examination suggested multifocal central nervous system involvement affecting the brainstem and cervico‐thoracolumbar spinal cord. Magnetic resonance imaging revealed diffuse meningeal thickening and contrast enhancement of the cerebrum and cranial cervical spinal cord, T2‐weighted and short tau inversion recovery intramedullary hyperintensity from L2 to L7, multifocal subdural empyema and diffuse paravertebral soft tissue hyperintensity. These findings were consistent with severe multifocal meningoencephalomyelitis with subdural empyema and paravertebral inflammation. Cerebrospinal fluid analysis revealed marked septic neutrophilic pleocytosis, and Streptococcus canis was isolated. Following cerebrospinal fluid collection, the patient developed signs consistent with brain death and was euthanased. Histopathology of the brain and cervical spine identified epidural suppurative bacterial infection with multifocal intravascular bacterial emboli, with some vessels nearly occluded by numerous colonies of Gram‐positive coccoid bacteria. No underlying predisposing condition was identified.