Dengue virus (DV) belongs to the family Flaviviridae, and its infection is characterized by dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. Some flaviviruses, such as Japanese encephalitis, St. Louis encephalitis, Murray Valley encephalitis, and West Nile viruses, have the common feature of neurovirulence in the human CNS, including poliomyelitis-like syndrome. 1 We report a patient with dengue fever who developed gray matter myelitis.Case report. A 42-year-old Japanese man working in Indonesia was admitted to a local hospital because of fever (38°C). Three days after admission, he had weakness in both legs and retained urine, and he was transferred to Singapore General Hospital. On admission, he was febrile and had a generalized macular rash. There was flaccid paralysis of the lower limbs with absent knee and ankle jerks. Sensation to pinprick was decreased below T6 segment. Laboratory examination revealed thrombocytopenia. Results of CSF examination were as follows: cells, 201/mm 3 (mononuclear cell dominant); glucose, 1.6 mmol/L; and protein, 100 mg/dL (normal, Ͻ45). The antibody index (normal, Ͻ1.00) ratio of anti-DV immunoglobulin (Ig) M to IgG was 3.32/1.64 in serum and was 6.02/1.37 in CSF. Results of plague neutralization assays indicated the presence of antibodies to DV type 1. The following serologies were all negative: antinuclear antibody, anti-doublestranded DNA, antiganglioside antibody, Venereal Disease Research Laboratory tests, poliovirus, HIV, human T-cell leukemia virus I, measles, mumps, rubella, yellow fever, enterovirus, herpes simplex virus, cytomegalovirus, and Epstein-Barr virus. CSF was negative for herpes simplex virus and enterovirus by PCR and culture and negative for a panel of neurotropic viruses (e.g., yellow fever, measles, mumps, and Japanese encephalitis virus) by complement fixation. CSF was also negative for oligoclonal bands, myelin basic protein, and fungi, mycobacteria, and bacteria by culture. MRI of the spine revealed swelling and an extensive high T2-weighted signal from the cervical spine to the conus medullaris. The patient was started on IV methylprednisolone and antibiotics. Two days after transfer, he developed respiratory distress and was intubated. He was normally alert but had complete tetraplegia and bilateral facial weakness. Further deterioration was evidenced by loss of upper limb reflexes and the ability only to grimace. He was started on IVIg, followed by plasmapheresis. Muscle weakness in face and neck gradually improved. He was transferred to Tokushima University Hospital during the third week of his illness. There was complete tetraplegia and mild sensory disturbance below the C7 segment. Routine blood examination was normal. CSF examination was as follows: 5 cells/mm 3 ; protein, 530 mg/dL; and IgG-albumin index, 0.958 (normal, Ͻ0.7). EMG showed moderate numbers of fibrillations in four extremities, indicating active denervation. Results of motor nerve conduction velocities were normal, but compound muscle action potential (CMAP) ampl...
