To report a case of human herpesvirus 6 (HHV-6) transverse myelitis in a healthy patient.

The extensive differential diagnosis of acute and subacute transverse myelitis requires timely diagnosis and investigations for better clinical outcomes. HHV-6 is a common childhood disease causing roseola that infrequently causes seizures and meningoencephalitis, but transverse myelitis is rare.

We present a 53-year-old healthy immunocompetent male without vaccination or radiation history presented with respiratory tract infection, myalgia,  paraparesis, subacute bilateral ascending paresthesias, urinary retention, constipation had upper motor neuron signs, positive Romberg's sign, sensory neuropathy, and a T8 sensory level.

MRI of the thoracic spine showed a long segmental T2 hyperintensity extending from T9 - T10 spinal cord segments without enhancement. CSF was suggestive of aseptic lymphocytic meningitis with pleocytosis and elevated protein. Oligoclonal bands were not detected. CSF  HHV-6 CSF PCR was positive. Otherwise, the CSF Meningitis/Encephalitis panel was negative.  HHV-6 viremia with 171,000 copies suggested HHV-6 was causing myelitis rather than a chromosomally integrated bystander.  CK was 925. HIV was negative. ACE levels were low. ANA, SS-A, SS-B, mycoplasma IgM, Lyme and VDRL, QuantiFERON gold, and Aquaporin 4 antibody were negative.  Hemoglobin A1c was 7.1.   Copper was 88.2, and ceruloplasmin was 19. B12 was 521, and folate was 13.6. He was treated with methylprednisolone 1 g daily for five days, along with valacyclovir and ganciclovir for two weeks, with subtle improvement of paraparesis and urinary retention.  This was followed by another two weeks of ganciclovir with subtle improvement of paresthesia and constipation but he was able to walk and work on his feet.

HHV-6 can rarely cause transverse myelitis in immunocompromised conditions and mimic other inflammatory and infectious pathologies. Timely diagnosis with chromosomal saturation and treatment could prevent life-threatening complications, including but not limited to rhabdomyolysis, paraparesis, urinary retention, and constipation.