Relation of clinical signs to pathological changes in 19 cases of canine distemper encephalomyelitis.

In an attempt to associate the clinical neurological syndromes with the neuropathological features of canine distemper (CD), 19 spontaneous cases with neurological involvement were examined, before and after euthanasia. Seventeen dogs were less than one year of age and all except two (89.4%) were unvaccinated against CD. Various extraneural signs associated with CD encephalomyelitis (CDE) were seen in 15 dogs. Generalized or localized myoclonus was the most common sign observed (13/19). Seventeen of the dogs presented with signs suggestive of one neuroanatomical location of lesions. Of these animals, seven had signs of cerebral, two of cerebellar, four of cervical, one of cervicothoracic, two of thoracolumbar and two of lumbosacral syndrome. The diagnosis of CD was confirmed immunohistochemically (detection of CD viral antigen), serologically (neutralizing serum antibody titre > or = 16) and histopathologically (CDV inclusion bodies, type of central nervous system lesions). An association of the neuroanatomical lesion location and the histopathological findings was noted in 14 out of 17 dogs (82.3%). Myoclonus could be attributed to lower motor neuron damage in eight out of 13 dogs (61.5%).