viral hepatitis C

Question 1

definition of viral hepatitis C

Answer 1

hep caused by HCV

often chronic course - 80% of cases

Question 2

structure of HCV

Answer 2

small, enveloped single stranded RNA virus of the flavivirus family

RNA virus = poor fidelity of replication = high mutation rates =- different HCV genetypes

even in a single parent many viral quasi-species may be present

Question 3

transmission of HCV

Answer 3

parenteral route

at risk gps:

• recipients of blood and blood products prior to screening
• IV drug users
• non-sterile acupuncture and tattooing
• haemodialysis
• healthcare workers

sexual and virtical transmission is uncommon - 1-5%, increased risk if co-infected with HIV

Question 4

pathology of HCV

Answer 4

it is hepatotrophic but not directly hepatotoxic

humoral and cell-mediated response -> hepatic inflammation and necrosis

on biopsy:

• chronic hepatitis is seen
• lyphoid follicles in the portal tracts - characteristic feature
• fatty change common
• features of cirrhosis may be common

Question 5

epidemiology of HCV

Answer 5

common

prevalence 0.5-2% in developed countries

UK prevalence >200000

higher rates in middle east - poor sterilisation

different genotypes have a different geographical prevalence

Question 6

sx of HCV

Answer 6

90% of acute infections are asymptomatic

jaundice

mild flu like illness

may be dx:

• after incidental abnormal LFT
• or in older individuals with complications of cirrhosis

Question 7

signs of HCV

Answer 7

maybe non e

signs of chronic liver disease in long standing infection

less common extrahepatic manifestations:

• skin rash - caused by mixed cryoglobulinaemia = small vessel vasculitis
• renal dysfunction caused by glomerulonephritis

Question 8

Ix for HCV

Answer 8

HCV serology - anti-HCV Ab - IgM (acute), IgG (past-exposure or chronic)

anti-HCV Ab confirms exposure

reverse transcriptase PCR - confirms ongoing infection/chronicity

LFT:

• acute = high AST and ALT and mildly raised BR
• chronic = 2-8x elevation of AST and ALT - fluctuating over time (can be normal)

liver biopsy or non-invasive elastography if HCV-PCR +ve to assess liver damage and need for treatment

determine HCV genotype

Question 9

reverse transcriptase PCR for HCV

Answer 9

detection and genotyping of HCV RNA

used to confirm Ab testing

also recommended when clinically suspected HCV but -ve serology

Question 10

liver biopsy for HCV

Answer 10

assess degree of inflammation and liver damage

transaminase levels have little correlation to histological changes

useful in dx cirrhosis - cirrhosis will need monitoring for hepatocellular ca

Question 11

prevention of HCV

Answer 11

screening of blood, blood products and organ donors

needle exchange schemes for IV drug abusers

instrument sterilisation

no vaccine available

Question 12

medical Mx of acute HCV

Answer 12

supportive - antipyretics, antiemetics, cholestyramine

specific antiviral treatment can be delayed for 3-6mo

Question 13

mx of chronic HCV

Answer 13

combined treatment with pegylated INF-a and ribavirin (guanosine nucleotide analogue)

HCV genotype 1 or 4 = 24-48wks

HCV genotype 2 or 3 = 12-24wks

inhibitors of non-structural viral proteins (ledipasvir + sofosbuvir)

Question 14

follow up Mx of HCV

Answer 14

monitoring HCV viral load for 12wks - determine the efficacy of treatment

regular US may be needed if cirrhosis

Question 15

complications of HCV

Answer 15

fulminant hepatic failure in acute phase - 0.5%

chronic HCV carriage

cirrhosis

hepatocellular ca

prophyria cutanea tarda

cryoglobulinaemia

glomerulonephritis

thyroiditis

autoimmune hepatitis

PAN

polymyositis

porphyria cutanea tarda

Question 16

Px of HCV

Answer 16

approx 80% of those exposed progress to chronic HCV infection

of these 20-30% develop cirrhosis over 10-20yrs

of these <4% get hepatocellular ca

Question 17

RF for progression

Answer 17

male

older

high viral load

use of alchol

HIV

HBV