Herpes Zoster (HZ) occurs from reactivation of latent Varicella-Zoster Virus (VZV) in dorsal root ganglia. Commonly associated neurological complications include cranial neuropathies and encephalitis. Longitudinally extensive transverse myelitis (LETM) as a complication of HZ has rarely been described in immunocompetent patients. We report a case of VZV-associated LETM occurring despite an appropriate course of acyclovir for HZ.

This 58-year-old immunocompetent male presented with HZ infection in right T4 dermatome. He received a full course of acyclovir. Three weeks later, he developed right chest numbness attributed to post-herpetic neuralgia and he received analgesics. A few days later presented to the ED with bilateral lower extremity weakness and numbness from the dermatome T4 level and below and was admitted for workup of myelopathy. The initial MRI was normal. He again received acyclovir for VZV-associated myelitis despite negative imaging. His CSF showed lymphocytic pleocytosis and high VZV IgG levels. Bloodwork and CSF analysis ruled out other infectious and autoimmune etiologies.  Five days later, MRI was again was unremarkable.  He developed rapidly progressive paraplegia. Thirteen days after admission, a third MRI showed a longitudinally extensive transverse myelitis that was contrast-enhancing and centrally located in the spinal cord from C7 to T6.  Decreasing the echo time on the STIR sequence helped make the diagnosis.   Plasma exchange treatment was attempted but he had an anaphylactic reaction to this treatment. He was ultimately treated with high dose IV steroids and five days of IVIG with poor functional outcome thus far.

VZV-associated LETM is an unusual complication of treated HZ. Although there is no standard treatment, acyclovir, IVIG and plasma exchange have been suggested as potential management options, ultimately with poor prognosis. Negative imaging long after symptom onset in our patient emphasizes the importance of a good neurological exam and repeat imaging to make the diagnosis.