• Save
Hcv
Upcoming SlideShare
Loading in...5
×
 

Hcv

on

  • 3,569 views

 

Statistics

Views

Total Views
3,569
Views on SlideShare
3,569
Embed Views
0

Actions

Likes
4
Downloads
0
Comments
2

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment
  • 7 7 7

Hcv Hcv Presentation Transcript

  • Hepatitis C Dr Kamran Afzal Asst Prof Microbiology
  • Introduction
    • Hepatitis C is a global problem
    • Most common chronic blood-borne infection
    • Worldwide, 200 million cases of HCV (3% of pop.)
    • Chronic HCV-associated liver disease is on rise
    • Pakistan (chronic liver disease) 14%
    • Laboratory has an important role in
      • Diagnosis
      • Pre treatment evaluation of the patient
      • Monitoring during treatment
      • Follow up after treatment
  • Historical background
    • Sporadic cases and outbreaks of jaundice
    • By the start of World War II- two types of jaundice, infectious and serum hepatitis were known
    • 1973 - Problem of parenterally transmitted non-A, non-B hepatitis (NANB)
    • 1988 - HCV first identified
    • 1989 - Serological test for HCV
  • HCV Virology
    • The virus has not been grown in culture
    • 50- 60 nm
    • Linear, single stranded RNA genome surrounded by an envelope carrying glycoprotein spikes
    • Daily production 10 12 virions
    • Now classified as Hepacivirus in the family of Flaviviridae
    • Some genotypes have high mutability
  • Hepatitis C Virus Genome hypervariable region capsid envelope protein protease/helicase RNA-dependent RNA polymerase c22 5’ core E1 E2 NS2 NS3 33c NS4 c-100 NS5 3’ Heterogeneity (results in difficulty in diagnosis, treatment and immunization)
  • Terminology Family Genus Species Genotype Subtype Quasispecies Flaviviridae Hepacivirus HCV
    • Genotype/ Subtypes
      • Genome heterogeneity among different HCV isolates
      • Varies from 31% to 35% of bases
      • 6 major genotypes and 120 subtypes
      • Genotypes 1 and 4 have worse prognosis and respond poorly to interferon while genotypes 2 and 3 respond well
    • Quasispecies
      • Population of closely related yet heterogeneous sequences within the same individual
      • The quasispecies vary from each other by 1% to 9% of bases
  • Distribution of HCV Genotypes
    • Exposure to blood / blood products, saliva, semen and cervical secretions
    • Parenteral transmission
      • Surgical/dental procedures
      • Transfusion of blood and blood products
      • Contaminated syringes/needles
      • Razors/ blades and other sharp instruments
      • I/V drug abusers
      • Organ transplants
    • Vertical transmission < 5%
    • Sexual transmission <3%
    Routes of Transmission
  • Routes of Transmission
  • Risk Groups
    • Health care workers
    • Staff at
      • Haemodialysis units
      • Surgical wards
      • Operation theatres
      • Cancer therapy units
    • Haemophiliacs and thallasaemics
    • Household and sexual contacts of infected patient
    • IV drug abusers
    • Male homosexuals or prostitutes
    • Vertical transmission in infants
  • Pathogenesis
    • Autoimmune damage particularly type II
    • Association of cytotoxic T-cells with HLA-I
    • Direct cytopathic effect
    • Co-infection with other viruses
      • HBV and HIV
  • Clinical Features
    • Incubation Period 12 weeks (2-26 weeks)
    • Asymptomatic cases
    • Symptoms occur in <25% of patients
      • Fatigue, malaise
      • Muscle and joint pains
      • Anorexia, nausea, abdominal pain
      • Low grade fever, weight loss and mild jaundice
    • Symptoms and signs of liver cirrhosis
      • Portal hypertension
      • Splenomegaly
      • Thrombocytopenia
  • Extrahepatic Manifestations
    • Glomerulonephritis
    • Thyroiditis
    • Cryoglobulinaemia
    • Porphyria cutanea tarda
    • ITP
    • Rare associations of HCV
      • Sero-negative arthritis
      • Keratoconjunctivitis sicca
      • Non Hodgkin B cell lymphoma
      • Lichen planus
  • Clinical Course Of Hepatitis C Acute Hepatitis 70-85% 15-30% Chronic Hepatitis Chronic Hepatitis 50% Recovery 20% Cirrhosis + or – HCC
  • Lab Diagnosis Serology ELISA Anti HCV Ab Core Ag RIBA Pathological Assays Liver biopsy FNAC Molecular Assays PCR RT- PCR b-DNA TMA Genotyping Biochem Raised SGOT Raised SGPT Raised S. Bil Deranged PT Radiological examination : Ultra sonography , CT
  • Serologic Pattern - Acute Symptoms +/- Time after Exposure Titer anti-HCV ALT Normal 0 1 2 3 4 5 6 1 2 3 4 Years Months HCV RNA 200 400 600 800 1000 Monophasic
  • Serologic Pattern - Chronic Symptoms +/- Time after Exposure Titer anti-HCV ALT Normal 0 2 4 6 1 2 3 4 Years Months HCV RNA 200 400 600 800 1000 Polyphasic
  • Liver Disease Patterns - ALT
    • Relapsing disease
      • ALT fluctuate widely, return to normal between exacerbations of disease, liver biopsy result variable
    • Continuous disease
      • ALT persistently high at low level, liver biopsy will show chronic hepatitis of variable severity
    • Healthy carrier
      • ALT normal, liver biopsy may be normal, but infective
  • Serological Techniques
    • Detection of anti HCV antibodies
    • ELISA (Enzyme Linked Immunosorbent Assay)
    • GENERATIONS PROTEINS
        • ELISA 1 NS4
        • ELISA 2 Core, NS3,NS4
        • ELISA 3 Core, NS3, NS4, NS5
        • ELISA 4 Core, NS3, NS4, NS5
    • RIBA (Recombinant Immunoblot Assay)
      • RIBA is confirmatory
      • Able to detect anti HCV antibodies in immunosuppressed
    • Anti HCV antibody
      • Screening tests
        • Fourth generation ELISA (Antigens: NS3 + NS4 + Core Protein + NS5)
        • Sensitivity – 100% in Immunocompetent and 50 – 95% in immunosuppressed and haemodialysis patients
        • Specificity – 99%
        • Anti HCV will not differentiate between acute and chronic HCV infection
      • Anti HCV IgM
        • Positive in 50 – 93% of acute HCV and in 50 – 70% of chronic HCV infection
  • Molecular Techniques
    • Polymerase chain reaction (PCR)
    • Ligase chain reaction (LCR)
    • Nucleic acid sequence based amplification (NASBA)
    • Strand displacement amplification (SDA)
    • Branched chain DNA amplification (bDNA)
    • Indications for PCR
    • Early diagnosis
    • Decision for interferon therapy
    • Monitoring the response to treatment
    • Genotype studies
    • Quantitative PCR
    • HCV RNA PCR – Qualitative
      • Hybridization methods
        • Not useful
        • HCV replicates at relatively low levels and viral genomes may be present only in small amounts
        • So amplification is necessary
      • Amplification methods
        • Polymerase chain reaction (RT-PCR)
        • Transcription mediated amplification (TMA)
      • Single Qualitative Positive test – Active viral replication
      • Single Qualitative Negative test – Probably a viral load below the detection limit of the assay – Repeat test
    • HCV RNA PCR – Quantitative
      • Target amplification methods
        • Real-Time PCR – Best method
        • Cut-off: 100 copies/ml
      • Signal amplification methods – bDNA assay
        • Cut-off: 200,000 copies/ml
    • HCV Genotyping
      • 6 genotypes and numerous subtypes
      • Genotyping – Direct sequencing of the NS5B or E1 region
      • Sub-typing is not necessary for treatment purposes
      • Methods – RFLP, Nested PCR, Reverse Hybridization, Direct sequencing, Serological detection of antibodies to genotype specific HCV epitopes
    • HCV Core antigen detection
      • Useful for screening in window period
      • Detected 1–2 days after HCV RNA positivity
      • Total HCV Core antigen quantification can be used as an alternate to HCV RNA PCR for treatment purposes
      • Low sensitivity
  • Interpretation of HCV Assays Anti-HCV HCV RNA Interpretation Positive Positive Acute or chronic hepatitis C depending on the clinical context Positive Negative Resolution of HCV; acute HCV during low-level viremia Negative Positive Early acute HCV; chronic HCV in immunosuppression; false positive Negative Negative No HCV infection
  • HCV Histological Presentation
    • Chronic active hepatitis
    • Liver cell degeneration and piecemeal necrosis with fibrosis
    • Chronic persistent hepatitis
    • Mononuclear infiltration, no necrosis
    • Chronic lobular hepatitis
    • Intralobular necro-inflammatory lesion
    • Cirrhosis
    • Fibrosis with conversion of normal architecture to abnormal lobules
    • Development of HCC
  • Liver Biopsy
    • Chronic hepatitis C with mild activity without fibrosis
    • KNODELL
    • HAI 3/18 (3/22)
    AFIP
    • Chronic hepatitis C with marked activity and cirrhosis
    • KNODELL
    • HAI 15/18 (19/22)
  • Goals for Treatment
    • To prevent the occurrence of cirrhosis and its complications
    • To reduce the extra hepatic manifestations
    • To prevent transmission to other people
    • (i.e. surgeon or drug user)
    • HCV Genotyping
    • Estimation of viral load
    • Liver Function Tests
    • Blood CP, platelets and ESR
    • Prothrombin time
    Pre Treatment Evaluation
    • Interferon
    • Ribavirin 6 to 12 months
      • End treatment response 50%
      • Sustained response 30%
    • Pegylated interferon
    • Liver transplantation
    Standard Recommended Treatment
  • Monitoring During Treatment
    • Blood CP and platelets Weekly - Initial 2 weeks
    • LFTs Fortnightly - First month
    • Monthly - Afterward
    • PCR at
      • 3 and 6 months – Response and dose adjustment
      • 12 months - End treatment response
      • 6 months after completion of treatment - Sustained response
    • Thyroid function tests (TSH) – Every 3-6 months during therapy
  • Chronology Of Tests After Treatment
    • Serum ALT
      • 3 months after completion of therapy
    • HCV RNA PCR
      • 6 months after the treatment
    • Liver biopsy
      • 1 year after completion of therapy
    •  - Fetoprotein
      • At annual intervals
  • Prevention and Control
    • Health education
    • Screening programs of donated blood, donated organs and donor’s awareness
    • Use of disposable syringes in true sense
    • Thorough and periodic sterilization of eqpt of ‘OT’, labour room, vascular catheterization, endoscopy and dental units must be ensured
  • Prevention and Control
    • Regular disinfection of worktops, furniture and mobile eqpt should be carried out
    • Ensure early detection of the disease
    • Monitoring of carriers
    • HCWs who are carriers of virus must not be allowed to deal with the patients
    • Barbers must be educated to sterilize their eqpt thoroughly
  •  
  • Guidelines for HCV RNA Testing CDC HCV RNA positive: patient is chronically infected HCV RNA negative: patient is most likely not infected, but low-level or Intermittent viremia possible. Repeat RNA testing recommended in 6-12 m Qualitative PCR or real-time PCR Chronic infection suspected HCV ab. positive
    • Check HCV RNA and HCV ab 4-6 wk after exposure
    • Check HCV RNA at 8-12 wk; if positive, consider therapy
    Qualitative PCR or real-time PCR Acute infection suspected Interpretation and Comments Test to Use Clinical Situation
  • Cont.. HCV RNA positive: patient is chronically infected HCV RNA negative: patient is most likely not infected, but low-level or Intermittent viremia possible. Repeat RNA testing recommended in 6-12 m Qualitative PCR or real-time PCR Infant born to HCV positive mother; infant still ab. positive at 18 m >800 000 IU/mL is considered high, more difficult to treat Use same quantitative assay before treatment and measure 4- and 12-wk responses Quantitative tests such as Quantitative qPCR, bDNA, or RT- PCR HCV antibody and RNA positive, eligible for treatment Interpretation and Comments Test to Use Clinical Situation
  • Conclusions
    • Every patient of hepatitis C does not require treatment
    • The management of patients is expensive due to the high cost of the drugs as well as reagent kits used for the testing of such patients
    • A judicious use of available laboratory facilities is imperative for a rational and cost effective management of such cases