viral hepatitis

viral hepatitis

1. hepatitis A

   • only host virus - humans
   • no reported cases of chronic hepatitis
     • major cause of acute hepatitis
       • most attacks are mild
   • mode of transmission: faecal-oral route
   • risk factors
     • international travels to endemic areas
     • sexual contact
     • shell fish with the virus
     • IV drug users + non-sterile needles
     • workers involved with primate animals
     • food service handlers
     • patients with clotting factors disorders
     • healthcare workers
     • household contact with infected person
   • diagnosis
     • antibodies to hepatitis A virus in the serum
       • IgM - usually present about 3 weeks post exposure; undetected within 6mths
       • IgG - present at the same time as IgM; indicates protection and lifelong immunity against infection
     • treatment
       • no drug treatment; only supportive
         • significant nausea, vomiting, diarrhoea and encephalopathy - hospitalisation required
   • prevention
     • good personal hygiene & proper sanitary waste disposal
     • immunoglobulin
       • IM preparation Provides passive immunity but not life long effective for pre and post exposure prophylaxis against hepatitis A
     • hepatitis A vaccine
       • -may be given alone or combined with typhoid vaccine -provides effective active immunity -adverse effects: *injection site reactions *headache *fatigue

2. hepatitis B

   • blood borne infection
     • highest conc of virus - blood & serous fluids
     • incubation period 3-6mths
   • may be acute or chronic
   • mode of transmission
     • blood or body fluids through peri-natal, sexual or IV drug use
     • blood transfusions from infected donors
     • sexual intercourse
   • risk factors
     • about 1/3 reported cases will have no identifiable risk factors
     • men having sex with other men
     • many heterosexual partners
     • use of non-sterile needles
     • recipients of blood products
     • household contact with hepatitis B with open wounds
     • healthcare providers with contact with contaminated needles
     • dialysis patients
   • diagnosis
     • surface antigen (HBsAg)
       • -first to be detected in blood -presence of recent infection -chronic infection if present for >6mths
     • envelope antigen (HBeAg)
       • -virus replication -active acute infection if HBV DNA is also present
     • antibodies to the core antigen (HBcAg)
       • -IgM indicates acute infection -IgG indicates chronic infection
     • virological marker: HBV DNA
       • Hepatitis B virus DNA -present in blood regardless of phase of infection -viral infectivity and quantify viral replication
   • prevention
     • avoid contaminated blood products or refrain from high risk behaviour
     • high risk patients should be vaccinated
       • IM for optimal effects 3 doses given injection should not be give in the gluteal region
     • immunoglobulin
       • give IM for passive immunity for post exposure prophylaxis
   • treatment
     • immune modulators eg interferons
       • help immune system to mount a defense against the virus
     • nucleoside/nucleotide analogues
       • suppress or destroy the hep B virus
     • adefovir, entecavir, lamivudine, telbivudine, tenofovir

3. hepatitis C

   • blood borne with greater infectivity than HIV
   • mode of transmission: blood and body fluids
   • often asymptomatic
   • about 85% develop chronic disease
   • leading indication for liver transplant worldwide
   • risk factors
     • blood product recipients
     • healthcare workers in contact with contaminated needles
     • having multiple sexual partners
     • perinatal transmission
     • unprofessional body piercing
   • diagnosis
     • test for anti-hepatitis C virus in serum
   • prevenion
     • avoid contaminated blood products or refrain from high risk behaviour
     • individuals at high risk should be testes since its asymptomatic
   • treatment
     • peginteferon plus ribavirin
       • peginteferon can be used as monotherapy if ribavirin is intolerated of CI
       • ribavirin
         • -excreted in semen -condom use if partners of infected men are pregnant -can cause gout -avoid if creatinine clearance is <50ml/min

4. hepatitis D

   • risk factors for transmission same as for hep B
   • can only cause infection in patients infected with hepatitis B
   • diagnosis
     • presence of hepatitis D virus RNA in the serum - most accurate diagnosis
   • hep B vaccine can prevent hep D

5. hepatitis E

   • faecal oral route
   • no chronic cases of hep E reported
   • risk factors
     • international travellers to endemic area
     • ingesting food thats contaminated with bodily waste
   • prevention
     • good personal hygiene and proper sanitary waste disposal
     • no vaccine available

6. fulminant hepatitis

   • liver transplant

7. acute - no drug treatment only supportive

8. symptoms & signs

   • mostly asymptomatic
   • flu-like symptoms, fever, fatigue, anorexia, N&V, diarrhoea, dark urine, pale stools, pruritus, abdominal pain
   • jaundice
   • hepatomegaly, splenomegaly, adenopathy
   • in fulminant hepatitis with hepatic encephalopathy patients may have asterixis and coma

9. treatment goals

   • prevent spread of infection
   • prevent and treat symptoms
   • suppress viral replication
   • normalise LFTs
   • improve histology on liver biopsy
   • decrease morbidity and mortality