Association of flavivirus infection in transverse myelitis

Abstract

In the majority of transverse myelitis (TM) an aetiology remains elusive. Viruses, autoimmune disorders and demyelinating diseases are the commonest among the causes identified. Viral association of TM could result from direct neurotropism or from the immune response to infection. The association of flaviviruses with TM has not been systematically studied. We aimed to characterize the association of flaviviruses with TM. Patients admitted to the National Hospital, Colombo, the largest tertiary-care hospital in Sri Lanka, were recruited and clinical, laboratory and radiological data were recorded. Serum was tested for IgM antibodies for dengue virus (DENV), Zika, West Nile (WNV) and Japanese encephalitis (JE). Pan-flaviviral PCR and real-time PCR was done to detect infection with DENV. Fifteen patients (10 males) were recruited with a mean age of 40 years (SD±16). Only 7 had associated or preceding fever. Fourteen had a sensory level (thoracic); seven had CSF pleocytosis; five of 12 had CSF:serum glucose ratio <0.5; two of 8 had demyelination on brain MRI; and five had longitudinally extensive transverse myelitis (LETM) on MRI. None had thrombocytopaenia or bleeding manifestations. PCR for DENV-2 was positive in 4 patients (27%) of whom none had LETM. PCR for pan-flaviviruses were negative in all. IgM antibodies to flaviviruses were detected in 4 patients (1 dengue, 1 JE and 2 WNV) Evidence of acute dengue infection of the central nervous system was seen in those with TM suggesting a possible aetiological association between dengue in TM.