Radiculomyelitic Rabies

We thank Desai et al (1) for an elegant corroboration of neuroimaging and pathology regarding a case of radiculomyelitic (paralytic or dumb) human rabies. Three previous reports of MR imaging of the spine in cases of human rabies appear in the literature (2–4). In one case of furious or encephalitic rabies, the findings of MR imaging of the lumbar spine were unremarkable (2). In two cases of paralytic rabies, the findings of MR imaging of the cervical spine were consistent with myelitis (3, 4).

Desai et al (1) argue that findings of MR imaging of the spine in cases of human rabies are different and that they distinguish rabies resulting from encephalomyelitis from rabies resulting from any other cause or, more specifically, from rabies occurring secondary to postexposure prophylaxis with inactive nerve tissue vaccines (ie, Semple vaccine). This claim seems premature, especially considering the limited data available. More descriptions of MR imaging of the spine in cases of human rabies are needed.

More important is the clear documentation of spinal abnormalities revealed by imaging in cases of paralytic human rabies. When MR imaging of the spine suggests myelitis, paralytic rabies should be considered. In a patient whose condition progresses from flaccid paralysis with myelitis evident on MR images of the spine to both paralysis and encephalitis, rabies should be strongly considered. Unfortunately, patients with rabies who did not receive appropriate postexposure prophylaxis will die, regardless of their neuroimaging findings.