Varicella Zoster Virus Myelitis in Two Elderly Patients: Diagnostic Value of Nested Polymerase Chain Reaction Assay and Antibody Index for Cerebrospinal Fluid Specimens
On April 5, 2011, an HIV-negative 73-year-old man developed right-chest dorsal zoster rash and was started on treatment with valacyclovir at 1 g orally three times a day. Despite this treatment, he developed severe anorexia, gait disturbance (on April 10) and urinary retention (on April 12), one after the other. On admission, on April 13, he was afebrile (36.8°C) and focal zoster rash was distributed in the dorsal Th 5–8 region. On neurological examination, he demonstrated moderate right flaccid leg weakness with hyporeflexia, slight right Babinsky sign and severe difficulty in urinating, but no sensory disturbance. Except for a surgical operation for gastric cancer at the age of 60, his medical and familial histories were unremarkable. Spinal cord MRI showed a high-signal-intensity lesion at Th 3–4 on a T2-weighted image (fig. and c). Laboratory studies showed no immunosuppression or autoantibody. The initial routine CSF studies showed lymphocytic pleocytosis (110 cells/µl), elevated proteins (93 mg/dl) and a negative result of bacterial culture (table ). The EIA value for IgG antibody was positive for VZV, HSV-1 and CMV in both serum and CSF (table ). Meanwhile, the EIA value for IgM antibody was negative against all three viruses in both serum and CSF (table ). The IgG antibody index was elevated against VZV (8.24), HSV-1 (7.30) and CMV (5.15), which suggested intrathecal synthesis of IgG antibodies (table ). In the CSF specimen collected on admission, no VZV DNA was detected by conventional commercial single-PCR assay (table ), but our original nested PCR assay revealed a definite positive result (table and fig. ). Based on these findings, he was diagnosed with VZV myelitis and radiculopathy and immediately treated with acyclovir at 10 mg/kg intravenously three times a day for 2 weeks and methylprednisolone at 1,000 mg intravenously daily for 3 days, and then dexamethasone at 10 mg intravenously (daily), tapering off by 2 mg every 4 days, parallel to rehabilitation. The treatment and rehabilitation succeeded, and his symptoms and routine CSF findings gradually improved. The results of nested PCR assay for CSF specimens rapidly changed from positive to negative 1 week after the start of treatment, whereas the IgG EIA value and the IgG antibody index for VZV were continually elevated throughout the course of clinical treatment (table ). Although severe anorexia remained as a sequela, his urinary retention was completely improved, and he recovered until he could walk with a walker. He was discharged to a rehabilitation hospital on May 26, 2011.