Fibromyalgia in hepatitis C virus infection. Another infectious disease relationship.

Background: Fibromyalgia syndrome (FS) is a common disorder of diffuse pain in the muscles or joints accompanied by tenderness at specific tender points and a constellation of related symptoms. The potential role of infections in the pathogenesis of FS has only recently been investigated.

Objectives: To evaluate the prevalence of FS and to assess tenderness thresholds in patients infected with hepatitis C virus (HCV).

Methods: The study included 90 patients with HCV, 128 healthy, anti-HCV-negative controls, and 32 patients with non-HCV-related cirrhosis. Tenderness was measured by manual palpation (18 tender points) and with a dolorimeter. Fibromyalgia syndrome was diagnosed according to the 1990 American College of Rheumatology criteria.

Results: The diagnosis of FS was established in 14 patients (16%) with HCV, in 1 patient (3%) with non-HCV-related cirrhosis, and in none of the healthy controls (P < .001). Thirteen of the HCV-positive patients with FS were women. The patients with HCV had significantly (P < .01) more tender points (mean [+/- SD] 3.6 +/- 5.3) than the healthy controls (0.1 +/- 0.5) and the patients with non-HCV-related cirrhosis (1.2 +/- 2.7). Specifically, the patients with cirrhosis were most tender on both tenderness measures owing to the high proportion of women in this group. Patients with FS were significantly more tender than those without FS: their dolorimetry thresholds were 2.9 kg vs 6.0 kg (P < .001).

Conclusions: A high prevalence of FS was observed in patients infected with HCV, especially women. Recognizing FS in patients with HCV will prevent misinterpretation of FS symptoms as part of the liver disease and will enable the physician to reassure the patient about these symptoms and to alleviate them.