Disseminated HSV-2 presenting with relapsing encephalomyelitis

Abstract

A previously healthy 39-year-old woman presented with 3 weeks of progressive leg numbness. Examination showed mild bilateral iliopsoas weakness and patchy leg numbness. She was admitted, and spinal MRI revealed T2 enhancing thoracic lesions, nonenhancing cervical cord lesions (figure, A), and subtle pial and cauda equina enhancement (figure, B). Brain MRI revealed multiple periventricular T2 hyperintensities (figure, C). Since the diagnosis of multiple sclerosis (MS) was considered likely, lumbar puncture (LP) was deferred and she received 5 days of IV methylprednisolone. One week later, she developed increasing right-sided hearing loss and vertigo with right cochlear enhancement (figure, D). Two weeks later, a morbilliform and vesicular flank and trunk rash appeared (figure, E and F). She was readmitted and treated with IV acyclovir for presumed disseminated varicella zoster virus (VZV). LP revealed a lymphocytic pleocytosis (90 leukocytes, 100% lymphocytes) and elevated protein (150 mg/dL). Oligoclonal bands were positive, and neuromyelitis optica and human T-cell lymphotropic virus-1 antibodies were negative. A PCR encephalitis panel was positive for herpes simplex virus (HSV)-2 and negative for VZV and HSV-1. Skin biopsy viral culture and PCR were positive for HSV. Three weeks after rash onset, the patient developed worsening leg numbness, received 5 more days of IV methylprednisolone, and soon after developed severe ataxia and weakness. Repeat MRI revealed new pontine lesions atypical for MS, punctate lesions following a vascular distribution, and new enhancing spinal cord lesions ( figure, G and H). Repeat LP revealed a decreasing leukocyte count (17 leukocytes) and rising protein (298 mg/dL). CSF HSV-2 PCR was now negative, yet quantitative ELISA revealed positive HSV-2 immunoglobulin G (IgG) (8.83 antibody index [AI]) and negative HSV-1 IgG (0.3 [reference range 0.9 AI]). CSF HSV-1 and HSV-2 immunoglobulin M (IgM) (1.15) and IgG titers were elevated (27.93 [reference range 0.9 AI]). A unifying diagnosis of HSV-2 encephalomyelitis was made. The patient was treated with plasmapheresis, followed by IV immunoglobulin (IVIG), concurrently with 6 weeks of IV acyclovir. A follow-up LP 3 weeks after treatment initiation demonstrated decreasing HSV IgM (0.22 AI) and IgG (7.96 AI) titers, pleocytosis (6 leukocytes), and protein (111 mg/dL), consistent with declining inflammation. Monthly follow-up imaging showed interval resolution of spinal enhancement and no new lesions, commensurate with resolving sensory symptoms and ataxia.