viral hepatitis

Annotations:

• 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
   6. prevention
      1. good personal hygiene & proper sanitary waste disposal
      2. immunoglobulin
      3. hepatitis A vaccine
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)
      2. envelope antigen (HBeAg)
      3. antibodies to the core antigen (HBcAg)
      4. virological marker: HBV DNA
   6. prevention
      1. avoid contaminated blood products or refrain from high risk behaviour
      2. high risk patients should be vaccinated
      3. immunoglobulin
   7. treatment
      1. immune modulators eg interferons
      2. nucleoside/nucleotide analogues
      3. adefovir, entecavir, lamivudine, telbivudine, tenofovir
3. hepatitis C
   1. 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
   2. diagnosis
      1. test for anti-hepatitis C virus in serum
   3. prevenion
      1. avoid contaminated blood products or refrain from high risk behaviour
      2. individuals at high risk should be testes since its asymptomatic
   4. treatment
      1. peginteferon plus ribavirin
         1. ribavirin
   5. caracteristics
      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
4. fulminant hepatitis
   1. liver transplant
5. acute - no drug treatment only supportive
6. signs and symptoms
7. hepatitis D
   1. Hepatitis D virus (HDV) is a virus that requires hepatitis B virus (HBV) for its replication. HDV infection occurs only simultaneously or as super-infection with HBV. The virus is transmitted through contact with the blood or other body fluids of an infected person. Vertical transmission from mother to child is rare.
   2. At least 5% of people with chronic HBV infection are co-infected with HDV, resulting in a total of 15 – 20 million persons infected with HDV worldwide. However, this is a broad global estimation since many countries do not report the prevalence of HDV. Worldwide, the overall number of HDV infection has decreased since 1980s. This trend is mainly due to a successful global HBV vaccination programme.
   3. HDV-HBV co-infection is considered the most severe form of chronic viral hepatitis due to more rapid progression towards liver-related death and hepatocellular carcinoma. Currently, treatment success rates are generally low. Hepatitis D infection can be prevented by hepatitis B immunization.
8. hepatitis E
   1. Hepatitis E is a liver disease caused by infection with a virus known as hepatitis E virus (HEV). Every year, there are an estimated 20 million HEV infections worldwide, leading to an estimated 3.3 million symptomatic cases of hepatitis E
   2. tansmission
      1. ingestion of undercooked meat or meat products derived from infected animals; transfusion of infected blood products; and vertical transmission from a pregnant woman to her fetus.
   3. Prevention
      1. maintaining quality standards for public water supplies; establishing proper disposal systems for human feces.
9. vaccines
10. bilirubin metabolism
11. jaundice
    1. Haemolytic jaundice
       1. Possible causes: sickle cell anemia or G6PD deficiency
       2. In haemolytic anaemia
       3. Presentation/Investigation ↑UCB ↑ Normal or Increased CB Urine and blood urobilinogen will be increased
    2. Hepatocellular Jaundice
       1. Reduced bilirubin conjugation as a result to the damaged hepatocytes such as in liver cirrhosis and hepatitis.
       2. ↑UCB ↑Urobilinogen in urine and blood ??? Dark urine (Urobilinogen) Pale stool ↑ AST and ALTCB
    3. Obstructive jaundice
       1. Obstruction in bile secretion that might be because of tumour or gallstone.
       2. GI pain and nausea, pale stools
       3. Because of extra hepatic cholestasis, CB increases in the blood . Dark urine (CB) Urobilinogen is absent