Hepatitis B is a DNA virus transmitted via parenteral, sexual, and vertical routes, with chronicity risk inversely related to age at infection (only ~5% of adult infections become chronic versus a majority of perinatal infections), and it is a leading cause of liver cancer worldwide; extrahepatic manifestations arise from immune complex-mediated vasculitis and glomerular disease, including polyarteritis nodosa (mesenteric/renal vasculitis), membranoproliferative glomerulonephritis, mononeuritis multiplex, and cryoglobulinemia. Diagnosis relies on the temporal appearance and interpretation of serologic markers (HBsAg, HBeAg, anti-HBe, anti-HBc IgM/IgG, anti-HBs) whose combinations distinguish acute infection, the window period, prior infection with immunity, vaccination, and chronic carrier versus active chronic states, situating this within internal medicine/hepatology and viral serologic diagnostics.
Hepatitis B is a DNA virus transmitted via parenteral, sexual, and vertical routes, with chronicity risk inversely related to age at infection (only ~5% of adult infections become chronic versus a ma…