Herpes simplex virus type 2 implicated in a case of acute disseminated encephalomyelitis

Introduction: Acute disseminated encephalomyelitis (ADEM) is a well-described neurological disorder that follows acute infection, vaccination, and organ transplantation. It is characterized by sudden and widespread areas of inflammation in the central nervous system. Previous case reports have described ADEM with evidence of either recent or current herpes simplex virus type 1 infection. However, here we report a rare, to our knowledge never before documented, case of ADEM associated with herpes simplex virus type 2 (HSV-2). Case report: A 20-year-old man presented with weakness and sensory disturbance to the lower limbs, which had gradually progressed over the preceding 7 days, with associated fever, urinary retention, and bowel incontinence. Magnetic resonance imaging was in keeping with a diagnosis of acute disseminated encephalomyelitis with mainly spinal involvement. Lumbar puncture revealed lymphocytic pleocytosis with elevated protein, and polymerase chain reaction was strongly positive for HSV-2. He was treated with aciclovir and dexamethasone, along with broad spectrum antibiotics until negative bacterial and mycobacterial culture results were obtained. His functional status improved over the following months, but, despite prolonged rehabilitation, neurological sequelae remain. Conclusion: HSV-2 should be considered a possible aetiological agent in cases of ADEM.