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Hepatitis

From Mediwikis

Presentation

Acute Symptoms

General:

  • Malaise
  • Aches
  • Fever
  • Nausea and vomiting
  • Diarrhoea
  • Headache

Specific:

  • Anorexia
  • Dark urine
  • Jaundice
  • Abdo pain
  • Hepatomegaly and splenomegaly

Chronic Symptoms

  • Malaise
  • Tiredness
  • Weakness
  • Asymptomatic

Advanced Disease:

  • Hepatomegaly
  • Jaundice

Can also progress to cirrhosis in advanced disease, which presents with:

  • Oedema
  • Ascites
  • Clotting problems
  • Hepatic-portal hypertension (oesophageal varices, haemorrhoids, caput medusa)

Hepatitis A Virus

RNA virus. Spread by faeco-oral route. Incubation period of 15–20 days. Typically less severe, transient infection.

Diagnosis

  • Faecal test – Hep A virus is excreted in the faeces towards the end of the incubation period
  • IgM antibodies – detectable 1–2 weeks after infection
  • IgG antibodies – acute illness has passed and the patient now has long-term immunity to further infection

Hepatitis B Virus

Serum levels of hepatitis B antigens (Source)

DNA virus. Spread by blood and bodily fluids. Liver damage caused by the body’s own cytotoxic T cells Chronic infection leads to a high risk of cirrhosis and hepatocellular carcinoma (related to the HBx antigen – HbxAg)

Diagnosis

  • HBsAg – Surface antigen, present during initial infection
  • HBcAg – Core antigen, present only in patients who have had a live infection (i.e. not in those who have been vaccinated)
  • HBeAg – Sign of increased viral activity and therefore high risk of contagion.
  • Anti HBc IgM – Antibody to core antigen, the initial, immediate immune response to the virus, indicating recent infection with Hepatitis B
  • Anti HBc IgG – antibody to core antigen, shows that the patient has long term immunity to the virus
  • ALT raises as the immune clearance begins, so will be found with HBcAg, and anti HBc (IgM initially).

Most diagnostic tests looks for HBsAg and the total anti HBc You can remain positive for HBsAg for over 6 months after initial infection, is this is the case then you are thought to be in a ‘carrier’ state. Carriers who are HBeAg negative have low viral activity, so there is a low chance of transmission and long term complications.

In chronic HBV infections:

  • HBsAg is found on the cell membrane of infected hepatocytes
  • HBcAg is found in the nucleus of infected hepatocytes

Hepatitis C Virus

RNA virus. Spread by blood. 80% of those who get infected develop chronic infection.

  • Chronic infection is typically asymptomatic until it develops to cirrhosis/HCC
  • HCV gives the worst type of chronic hepatitis; highest rate of progressing to HCC

Commonly develop fatty liver. There are 6 genotypes of HCV. Type 2 and 3 respond well to treatment, whereas types 1 and 4 respond badly to treatment, therefore it is important to establish what type of HCV the patient is infected with.

Diagnosis

  • HCV RNA PCR – can be used 2wks after initial infection, can be used to determine viral load
  • HCV antibodies – take longer to form and be detected
    • Immuno assay is the initial test
    • Immuno blot is the confirmatory test

If HCV antibodies are present but the RNA PCR is negative then the infection has been cleared.

Hepatitis E Virus

RNA virus Transmitted by faecal-oral route Clinically similar to Hep A, but is much more serious in pregnant women as can progress to acute liver failure.