The Association of Hepatitis B and Polymyositis: Rare but Real

Aims: Hepatitis B virus infection is a global health concern. Although Hepatitis B virus primarily affects hepatocytes, it sometimes develops disease manifestations outside the liver and can present as full fledged proximal myopathy.  Presentation of Case: We report a 68-year-old man presenting with progressive proximal bilateral lower limb weakness for the last 14 days. The weakness was associated with pain and one episode of fever. Examination revealed 3/5 power in the shoulder and hip joint without any sensory deficit. Biochemical investigation showed elevated CPK levels (1102 IU/L) and liver enzymes (AST – 625 IU/L, ALT – 356 IU/L). HBsAg and HBeAg came out to be positive with HBV DNA of 73000 copies/mL. MRI shoulder and hip joints revealed diffuse intramuscular and myofascial edema suggesting inflammatory myositis. Muscle biopsy was suggestive of Necrotizing Autoimmune Myopathy. Discussion: Patient symptoms improved after starting IV Prednisolone and Entecavir therapy suggesting a close association between Hepatitis B infection and myopathy. Conclusion: Although Hepatitis B virus primarily affects hepatocytes, it sometimes develops disease manifestations outside the liver, such as Polymyositis. Therefore, it is imperative to screen for Viral markers in these patients.