Varicella zoster virus encephalomyelitis as a late complication following haematopoietic stem cell transplantation.

Varicella zoster virus (VZV) causes the primary infection manifesting as varicella or chickenpox, with possibility of reactivation later in life. A 71-year-old man presented with headache and lower extremity weakness. There was no evidence of skin lesions to suggest a recent zoster infection. The patient had a history of multiple myeloma diagnosed 2 years earlier, treated with chemotherapy and autologous stem cell transplant. Antimicrobial prophylaxis was discontinued 12 months after the transplant. MRI of the brain demonstrated areas of T2/fluid-attenuated inversion recovery hyperintensity in bilateral cerebral white matter and MRI of the spine demonstrated enhancement along the cauda equine. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis and VZV DNA was detected by PCR in the CSF. The patient was treated with 8 weeks of antiviral therapy with complete resolution of symptoms. VZV should be considered in patients with haematopoietic stem cell transplantation presenting with similar neurological manifestations even in the absence of dermatological signs.