Varicella Zoster Virus Myelitis in Two Elderly Patients: Diagnostic Value of Nested Polymerase Chain Reaction Assay and Antibody Index for Cerebrospinal Fluid Specimens
On February 26, 2010, a previously healthy and HIV-negative 79-year-old woman developed mild fever and focal skin rash with pain in her gluteal region. Moreover, on March 9, she developed gradually progressive gait disturbance. On admission, on March 11, her temperature was 37.6°C and focal zoster rash was distributed in the sacral 2–3 gluteal region. Upon neurological examination, she demonstrated mild right hand weakness, moderate left dominant paraplegia with bilateral hyporeflexia of the lower limbs, and numbness with decreased sensation in the left arm and bilateral trunk and legs below thoracic (Th)-10. Both planter responses were absent. Spinal cord MRI showed a high-signal-intensity lesion at the cervical spinal nerve 2 on a T2-weighted image (fig. ). Laboratory studies showed no immunosuppression or autoantibody. The initial routine CSF studies showed lymphocytic pleocytosis (156 cells/µl), elevated proteins (155 mg/dl) and a negative result for bacterial culture (table ). EIA values for IgG antibodies was positive against VZV, HSV-1 and CMV in both serum and CSF (table ). The EIA value for IgM antibody was only positive against VZV in serum, but negative against all three viruses in CSF (table ). The IgG antibody index was elevated against VZV (3.28) and HSV-1 (2.25), which suggested intrathecal synthesis of IgG antibodies (table ). In a CSF specimen collected on admission, no VZV DNA was detected by the conventional commercial single-PCR assay (table ), but our original nested PCR assay revealed a clear positive result for the same CSF specimen (table and fig. ). Based on these findings, the patient was diagnosed with VZV myelitis and immediately treated with acyclovir at 10 mg/kg intravenously three times a day for 2 weeks and methylprednisolone at 500 mg intravenously daily for 3 days, parallel to rehabilitation. The treatment and rehabilitation succeeded and her 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 starting treatment, whereas the IgG EIA value and IgG antibody index for VZV were continually elevated throughout the course of clinical treatment (table ). Although numbness in the distal part of both lower limbs remained as a sequela, the patient recovered until she could walk without any assistance. She was discharged on May 10, 2010.