## Distinguishing Chronic Hepatitis B from Chronic Hepatitis C ### Extrahepatic Manifestations Comparison | Feature | Chronic HBV | Chronic HCV | |---------|-------------|-------------| | **Cryoglobulinemia** | Rare | Common (50–60%) | | **MPGN / GN** | Immune complex-mediated (HBsAg-anti-HBs) | Cryoglobulin-mediated | | **Arthritis** | HBsAg-related | Rare | | **Polyarteritis nodosa** | Associated | Not associated | | **Sjögren syndrome** | Not associated | Associated | | **Lymphoid aggregates** | Absent or minimal | Prominent (hallmark) | | **HCC without cirrhosis** | Can occur | Rare | ### Key Point: **Cryoglobulinemia and membranoproliferative glomerulonephritis (MPGN) are the most specific extrahepatic manifestations of chronic hepatitis C.** These occur in 50–60% of HCV patients and are mediated by HCV-related mixed cryoglobulins (IgM with rheumatoid factor activity). HBV-related extrahepatic disease (polyarteritis nodosa, glomerulonephritis) is less common and has a different immunological basis (HBsAg-anti-HBs immune complexes). ### High-Yield: Cryoglobulinemia → HCV. Polyarteritis nodosa → HBV. This mnemonic helps distinguish the two viruses by their extrahepatic complications. ### Clinical Pearl: A patient with cirrhosis, positive HCV serology, and concurrent glomerulonephritis or cryoglobulinemia should be investigated for HCV-related cryoglobulinemia. This finding is so characteristic of HCV that it can help clinically distinguish HCV from HBV even in dual-positive patients. [cite:Robbins 10e Ch 18; Harrison 21e Ch 347]
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