What you need to know about infectious myelopathies
The Ixodes tick (above) is the agent of transmission of lyme disease, one of several infections that can affect the spinal cord. More often, lyme disease is characterized by meningitis with or without cranial nerve palsies (frequently involving the facial nerve). But occasionally, infections from Borrelia burgdorferi can result in a transverse myelitis or radiculitis with pain, weakness, or numbness in the arms and legs. Lyme disease is one of several infectious causes of myelitis, which are reviewed by BrainWaves in this episode:
What makes this episode interesting is that we have illustrated the similarities and differences between infectious causes of myelopathy and nutritional or degenerative diseases. For example, amyotrophic lateral sclerosis results in progressive destruction of the anterior horn alpha motor neurons, not unlike that seen in poliomyelitis, enterovirus D68 associated flaccid paralysis, and west nile virus myelitis. HIV, in contrast, produces a myelopathy that is vacuolar on histopathology, and can radiographically mimic the classic subacute combined degeneration of B12 deficiency. Because of the way some infections preferentially target various elements of the spinal column, the clinical and radiographic localization of spinal cord dysfunction is invaluable for the differential diagnosis of myelopathy.
Other causes of myelitis and myelopathy are topics beyond the scope of this BrainWaves brief. We focus largely on infections that involve the intrinsic spinal cord. It would have been great to talk about Pott’s disease or spinal cord abscesses, however these typically result in extramedullary compression of the spinal cord with a resultant compressive myelopathy. That being said, abscesses can be intramedullary (rarely), and there is not really one bacterium or fungi that likes to nestle into the cord more than any other. The viruses and spirochetes like Borrelia and T. pallidum are the subject of our conversation here.
Cho TA, Vaitkevicius H. Infectious myelopathies. Continuum (Minneap Minn). 2012;18(6):1351-1373.