Viral Hepatitis

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Viral Hepatitis

  1. 1. Viral Hepatitis <ul><li>In the mid 1960s, Blumberg and colleagues discovered </li></ul><ul><li>surface Ag and Ab of hepatitis B, this opened the door to </li></ul><ul><li>morphological and immunochemical features of other </li></ul><ul><li>forms of viral hepatitis </li></ul><ul><li>In 1990 HCV was discovered as a causative agent for </li></ul><ul><li>post transfusion non A non B hepatitis </li></ul><ul><li>There are five major types of viral hepatitis A,B,C,E,D </li></ul>
  2. 2. Hepatitis C virus (HCV) <ul><li>Single strand RNA virus </li></ul><ul><li>Morpholopy of HCV Genomic organization of HCV </li></ul><ul><li>The viral replication is error prone (mutation), </li></ul><ul><li>which enable the production of different genotypes </li></ul><ul><li>(1-11 main genotype) </li></ul>
  3. 3. Epidemiology <ul><li>WHO report prevalence 3% in the world population </li></ul><ul><li>Prevalence of HCV in Thai blood donor </li></ul><ul><li>Province/Region year study % HCV positive </li></ul><ul><li>Bangkok 1992 1.38 </li></ul><ul><li>Chiengmai 1994 2.4 </li></ul><ul><li>North-East 1997 5.6 </li></ul><ul><li>Prevalence by genotype: 3a(38 % ), 1a(21 % ), 1b(18 % ), 6a(7 % ),3b(6 % ) </li></ul>
  4. 4. Sources of Infection: parenteral <ul><li>Blood transfusion or organ transplantation </li></ul><ul><li>(especially before 1992) : </li></ul><ul><li>60 % of chronic HCV in Thailand </li></ul><ul><li>2. Intravenous drug user: 5.3 % in Thailand </li></ul><ul><li>3. Medical, dental procedure, tattu </li></ul><ul><li>4. Sexual contact: chance 5-6 % </li></ul><ul><li>5. Vertical transmission chance 5-6 % </li></ul><ul><li>6. Unknown or household contact: up to 40 % </li></ul>
  5. 5. Sources of infection (CDC USA)
  6. 6. Clinical Manifestation <ul><li>IP: 7-8 weeks (range 2-12 weeks) </li></ul><ul><li>Acute hepatitis: flu-like symptoms, jaundice (≤20%), abdominal pain </li></ul><ul><li>Chronic hepatitis (70-80 % ): positive anti HCV or abnormal SGOT, </li></ul><ul><li>SGPT on check up or screening, symptom of fatigue, </li></ul><ul><li>sign of chronic liver disease (cirrhosis, portal HT, </li></ul><ul><li>palmar erythema, spider nevi) </li></ul><ul><li>Extrahepatic manifestation: (Autoimmune manifestation): </li></ul><ul><ul><ul><li>Arthralgia, arthritis, myalgia </li></ul></ul></ul><ul><ul><ul><li>Thrombocytopenia, perpura, Raynaud’s phenomenon </li></ul></ul></ul><ul><ul><ul><li>Membranoproliferative glomerulonephritis </li></ul></ul></ul><ul><ul><ul><li>Thyroiditis </li></ul></ul></ul><ul><ul><ul><li>Abnormal blood test: ANA (40 % ) speckle pattern </li></ul></ul></ul><ul><li>RF(70 % ), anticardiolipin Ab (27 % ), </li></ul><ul><li>cryoglobulin (36%), antithyroglobulin (13 % ) </li></ul>
  7. 7. Serologic pattern of HCV infection
  8. 8. Natural Hx of hepatitis C <ul><li>20-30 % of acutely infected patient who recover may retain </li></ul><ul><li>anti HCV for several years </li></ul><ul><li>In a small group (27 %) , viremia is persistent or intermittent, </li></ul><ul><li>but serum ALT level are usually normal, this group have </li></ul><ul><li>a lower likelihood of progression to cirrhosis </li></ul><ul><li>In the group with persistently or intermittently elevated ALT, </li></ul><ul><li>the median duration for cirrhosis and HCC are 20 </li></ul><ul><li>and 28 yrs, respectively. </li></ul><ul><li>Cirrhosis occur in 20 % , HCC 1-4 % /year </li></ul><ul><li>Factors promoting progression of disease: age> 40 yrs at time of </li></ul><ul><li>infection, increased alcohol intake, male, co-infection with </li></ul><ul><li>HIV, HBV, degree of liver inflammation and fibrosis from </li></ul><ul><li>liver Bx. </li></ul>
  9. 9. Diagnosis of hepatitis C <ul><li>Medical Hx of risk factors and symptoms </li></ul><ul><li>Blood test: CBC, LFT, coagulogram, </li></ul><ul><li>: Specific test for HCV </li></ul>
  10. 10. Specific Test for HCV <ul><li>Anti HCV: detect antibody in serum by EIA </li></ul><ul><li>Anti HCV Antigen Sensitivity (%) </li></ul><ul><li> EIA-1 NS4 70-80 </li></ul><ul><li> EIA-2 core/NS3 92-95 </li></ul><ul><li> EIA-3 core/NS3/NS5 ≥ 99 </li></ul><ul><li>Confirmation test by RIBA: detect different antibody to HCV antigen by recombinant immunoblot assay (2 bands positive at least) </li></ul><ul><li>HCV-RNA: </li></ul><ul><ul><ul><ul><li>Qualitative test : RT-PCR </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Quantitative : PCR, bDNA </li></ul></ul></ul></ul><ul><li>HCV RNA PCR < 100 copies/ml : negative </li></ul><ul><li>200,000-1,000,000 : low </li></ul><ul><li>1,000,000-5,000,000 : medium </li></ul><ul><li>5,000,000-25,000,000 : high </li></ul><ul><li>> 25,000,000 : very high </li></ul>
  11. 11. Anti HCV test ; A: EIA B: RIBA A B
  12. 12. Interpretation of Anti-HCV Test Anti-HCV Anti-HCV HCV-RNA Interpretation EIA RIBA Positive Positive Positive Current infection Positive Positive Negative Intermittent viremia or resolved infection Positive Negative - Uninfected Negative - - Uninfected Positive Indeterminate Negative False positive anti HCV test Positive Indeterminate Positive *Recent HCV infection *Persistent finding in some chronic HCV
  13. 13. Anti HCV screening test, RIBA and HCV RNA result In groups with different HCV prevalence HCV prevalence Total test No(%) RIBA result(%) HCV RNA positive Neg Ind. Pos positive (%) 0.8-4.4% 24,012 689 27 7 66 41* 9.5% 2,936 351 10 7 83 80 24.9% 498 124 2 4 94 NA+ *: only 214 sample were test for HCV RNA *: Not assess
  14. 14. Treatment of Chronic Hepatitis C Indication : ALT level >1.5 x upper normal limit on three consecutive occasions ≥ 3 months : Liver Bx indicate active disease Regimen : Combination of Interferon alpha 3 MU TIW and ribavirin 1000-1200 mg/d x 24 weeks for genotye 2 and 3 and 48 weeks for genotype 1 Successful treatment : clearance of HCV RNA from serum 6 month after therapy

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