viral hepatitis

Anotações:

• differ by: -mode of transmission -liver damage they cause -how they affect health Most common cause of liver disease worldwide. Mild attacks are asymptomatic. May be acute or chronic. Can occur at any age.
• acute viral hepatitis:  - <6mths  -observed with all types chronic viral hepatitis: -viremia and hepatic inflammation >6mths following infection -hep B,C and D -may lead to cirrhosis and end stage liver disease

1. hepatitis A
   1. only host virus - humans
   2. no reported cases of chronic hepatitis
      1. major cause of acute hepatitis
         1. most attacks are mild
   3. mode of transmission: faecal-oral route
   4. risk factors
      1. international travels to endemic areas
      2. sexual contact
      3. shell fish with the virus
      4. IV drug users + non-sterile needles
      5. workers involved with primate animals
      6. food service handlers
      7. patients with clotting factors disorders
      8. healthcare workers
      9. household contact with infected person
   5. diagnosis
      1. antibodies to hepatitis A virus in the serum
         1. IgM - usually present about 3 weeks post exposure; undetected within 6mths
         2. IgG - present at the same time as IgM; indicates protection and lifelong immunity against infection
      2. treatment
         1. no drug treatment; only supportive

            Anotações:

            • significant nausea, vomiting, diarrhoea and encephalopathy - hospitalisation required
   6. prevention
      1. good personal hygiene & proper sanitary waste disposal
      2. immunoglobulin

         Anotações:

         • IM preparation Provides passive immunity but not life long effective for pre and post exposure prophylaxis against hepatitis A
      3. hepatitis A vaccine

         Anotações:

         • -may be given alone or combined with typhoid vaccine -provides effective active immunity -adverse effects: *injection site reactions *headache *fatigue
2. hepatitis B
   1. blood borne infection
      1. highest conc of virus - blood & serous fluids
      2. incubation period 3-6mths
   2. may be acute or chronic
   3. mode of transmission
      1. blood or body fluids through peri-natal, sexual or IV drug use
      2. blood transfusions from infected donors
      3. sexual intercourse
   4. risk factors
      1. about 1/3 reported cases will have no identifiable risk factors
      2. men having sex with other men
      3. many heterosexual partners
      4. use of non-sterile needles
      5. recipients of blood products
      6. household contact with hepatitis B with open wounds
      7. healthcare providers with contact with contaminated needles
      8. dialysis patients
   5. diagnosis
      1. surface antigen (HBsAg)

         Anotações:

         • -first to be detected in blood -presence of recent infection -chronic infection if present for >6mths
      2. envelope antigen (HBeAg)

         Anotações:

         • -virus replication -active acute infection if HBV DNA is also present
      3. antibodies to the core antigen (HBcAg)

         Anotações:

         • -IgM indicates acute infection -IgG indicates chronic infection
      4. virological marker: HBV DNA

         Anotações:

         • Hepatitis B virus DNA -present in blood regardless of phase of infection -viral infectivity and quantify viral replication
   6. prevention
      1. avoid contaminated blood products or refrain from high risk behaviour
      2. high risk patients should be vaccinated

         Anotações:

         • IM for optimal effects 3 doses given injection should not be give in the gluteal region
      3. immunoglobulin

         Anotações:

         • give IM for passive immunity for post exposure prophylaxis
   7. treatment
      1. immune modulators eg interferons

         Anotações:

         • help immune system to mount a defense against the virus
      2. nucleoside/nucleotide analogues

         Anotações:

         • suppress or destroy the hep B virus
      3. adefovir, entecavir, lamivudine, telbivudine, tenofovir
3. hepatitis C
   1. blood borne with greater infectivity than HIV
   2. mode of transmission: blood and body fluids
   3. often asymptomatic
   4. about 85% develop chronic disease
   5. leading indication for liver transplant worldwide
   6. risk factors
      1. blood product recipients
      2. healthcare workers in contact with contaminated needles
      3. having multiple sexual partners
      4. perinatal transmission
      5. unprofessional body piercing
   7. diagnosis
      1. test for anti-hepatitis C virus in serum
   8. prevenion
      1. avoid contaminated blood products or refrain from high risk behaviour
      2. individuals at high risk should be testes since its asymptomatic
   9. treatment
      1. peginteferon plus ribavirin

         Anotações:

         • peginteferon can be used as monotherapy if ribavirin is intolerated of CI
         1. ribavirin

            Anotações:

            • -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
   1. risk factors for transmission same as for hep B
   2. can only cause infection in patients infected with hepatitis B
   3. diagnosis
      1. presence of hepatitis D virus RNA in the serum - most accurate diagnosis
   4. hep B vaccine can prevent hep D
5. hepatitis E
   1. faecal oral route
   2. no chronic cases of hep E reported
   3. risk factors
      1. international travellers to endemic area
      2. ingesting food thats contaminated with bodily waste
   4. prevention
      1. good personal hygiene and proper sanitary waste disposal
      2. no vaccine available
6. fulminant hepatitis
   1. liver transplant
7. acute - no drug treatment only supportive
8. symptoms & signs
   1. mostly asymptomatic
   2. flu-like symptoms, fever, fatigue, anorexia, N&V, diarrhoea, dark urine, pale stools, pruritus, abdominal pain
   3. jaundice
   4. hepatomegaly, splenomegaly, adenopathy
   5. in fulminant hepatitis with hepatic encephalopathy patients may have asterixis and coma
9. treatment goals
   1. prevent spread of infection
   2. prevent and treat symptoms
   3. suppress viral replication
   4. normalise LFTs
   5. improve histology on liver biopsy
   6. decrease morbidity and mortality