Fibromyalgia and chronic hepatitis C infection share many clinical features including prominent somatic complaints such as musculoskeletal pain and fatigue. In fact, some medical experts believe that the symptoms and presenting patterns in common between hepatitis C and fibromyalgia are not coincidental. There is the possibility that hepatitis C may be a trigger of fibromyalgia.
There is a growing body of evidence supporting a link between cytokines and somatic complaints. There have been reports of alterations of cytokines in fibromyalgia, including increased serum levels of interleukin (IL)-2, IL-2 receptor, IL-8, IL-1 receptor antagonist, and increased IL-1 and IL-6 produced in patients with fibromyalgia for longer than 2 years, to name but a few.
Alterations in the cytokines of fibromyalgia and chronic hepatitis C infection can produce hyperalgesia and other neurologically-mediated complaints, as the cytokine receptors can be found on brain cells and opiate receptors on blood cells.
Many individuals with other liver diseases do not suffer the pain seen in hepatitis C. And there is a high prevalence of fibromyalgia in hepatitis C patients; this is important for clinicians to appreciate, as the recognition of fibromyalgia in patient with hepatitis C will prevent assumptions of pain being due to liver disease—and perhaps allow for a more focused and correct treatment approach.