Isolation of varicella zoster virus from the synovial fluid of a patient with herpes zoster arthritis.

Only a few cases of herpes zoster-associated arthritis have been reported to date (1-3). This form of arthritis is presumed to be viral in origin. Isolation of varicella zoster virus (VZV) by culture from synovial fluid has not been previously documented. VZV infection of the joint space associated with acute arthritis has been evidenced only once, by the finding of VZV antigen in the joint fluid (1). However, VZV has been isolated from the joint fluid of several children with chickenpox-associated arthritis ( 4 3 . We report herein the first case of documented isolation of VZV from synovial fluid in an adult with zoster-associated arthritis. A 67-year-old man presented with a warm, swollen, painful right knee associated with an erythematous rash with grouped vesicles over the L5 dermatome. Symptoms had begun 3 days earlier without fever. Aspiration of synovial fluid 4 days after the onset of arthritis symptoms yielded 40 ml of straw-colored fluid. The synovial fluid leukocyte count was 17,600/mm3, with 44% lymphocytes and 56% polymorphonuclear cells. Findings on blood and synovial bacteriologic cultures were negative. The blood leukocyte count was 4,400/mm3, and the erythrocyte sedimentation rate was 5 mdhour . The aspirated joint fluid was immediately inoculated onto a culture plate of human fibroblast cells. A typical cytopathic effect was demonstrated 10 days after the inoculation. The tentative identification of VZV was confirmed by immunofluorescence staining using a specific monoclonal antibody (clone 2013; Biosoft, Paris, France). The serum VZV antibody titer as determined by enzyme-linked immunosorbent assay (Behring, Marburg, Germany) was > 15,120. The symptoms resolved spontaneously within 72 hours, without sequelae. Arthritis caused by direct viral infection in the joint space is seldom documented. Rubella virus (6), vaccinia virus (7), herpes simplex virus (8), cytomegalovirus (8), echovirus (9), and VZV in association with chickenpox (43) have been cultured from the synovial fluid of patients with acute arthritis. Isolation of VZV from the joint fluid of our patient with herpes zoster eruption, in the absence of a bacterial pathogen, is strong presumptive evidence that the virus caused the arthritis. In previously reported cases of herpes zoster-associated arthritis (1-3), the arthritis involved one large joint (knee, hip). In 2 cases (2,3) it began 2 or 3 days before the onset of the typical vesicular rash, and the skin rash and joint pain resolved completely without treatment within 8-10 days. The leukocyte counts in aspirated joint fluid were low, ranging from 2,000 to 9,000/mm3 (1). To our knowledge, findings on viral cultures were always negative. Our ability to isolate VZV from the joint fluid in this case, confirming the diagnosis, was probably due to early sampling and immediate inoculation of the fluid into culture cells. However, we again isolated the virus when the joint fluid, which had been frozen and stored at -80°C for 5 days, was reexamined. In view of the lack of reports of isolation of VZV from synovial fluid, efforts were made to confirm the identity of the cytopathic agent. It was indeed identified as VZV, not only by the characteristic cytopathic effect, but by positive immunofluorescence staining using a monoclonal antibody.