Viral hepatitis Flashcards
What is hepatitis A&E?
- HAV ⇒ RNA picornavirus. HEV ⇒ calicivirus. Both transmitted via faecal-oral route.
- HAV → endemic in the developing world. Infection often occurs sub-clinically. Better sanitisation in developed world means it is less common.
- HEV → endemic in Asia, Africa and Central America.
- Hep A = particularly associated with travellers
- Both have incubation period of 3-6 weeks.
- Severe Hepatitis in pregnant women = Hep E. - Acute infection only
What are the risk factors for hepA&E?
- Risk factors:
- Living in endemic region
- Close personal contact with an infected person
- Men who have sex with men
- Known foodborne outbreak
Summarise the epidemiology of viral hepatitis
- HAV is endemic in the developing world
- Infection often occurs sub-clinically (no clinical findings)
- Better sanitation in the developed world means that it is less common, age of exposure is higher and, hence, patients are more likely to be symptomatic
- Annual UK incidence: 5000
- HEV is endemic in Asia, Africa and Central America
What are the presenting symptoms of hepA&E?
- Incubation period of HAV and HEV: 3-6 weeks
- Prodromal period symptoms (early symptoms)
- Malaise
- Anorexia – distaste for cigarettes in smokers
- Fever
- Nausea and vomiting - Hepatitis symptoms:
- Dark urine
- Pale stools
- Jaundice lasting around 3 weeks
- Occasionally, itching and jaundice may last several weeks in HAV infection
What signs of viral hepatitis A&E can be found on physical examination
- Pyrexia
- Jaundice
- Tender hepatomegaly
- Spleen may be palpable
- ABSENCE of stigmata of chronic liver disease (although some spider naevi may appear transiently)
What investigations are used to diagnose/ monitor hepatitis A&E?
- LFT’s → raised AST, ALT, ALP, GGT and bilirubin
- Raised ESR
- Severe → low albumin + high platelets
- Serology:
- HAV ⇒ Anti-HAV IgM present during acute illness, disappears after 3-5 months. Anti-HAV IgG persist indefinitely after infection or vaccination.
- HEV ⇒ Anti-HEV IgM for active infection, Anti-HEV IgG for past infection.
How is hepatitis A&E managed?
- Symptomatic Treatment (+ use drugs such as paracetamol with caution due to hepatotoxicity)
- Hepatitis A Vaccine (no vaccine for HEV)
- Avoid alcohol and excess paracetamol
What complications may arise from hepatitis A&E?
- Fulminant hepatic failure (in a very small proportion of patients but is more common in pregnant women)
- Cholestatic hepatitis with prolonged jaundice and pruritus can develop after HAV infection
- Post-hepatitis syndrome: continued malaise for weeks to months
Summarise the prognosis for patients with viral hepatitis
- Recovery is usually within 3-6 weeks
- Occasionally patients may relapse during recovery
- There are no chronic sequelae
- Fulminant hepatic failure has a mortality of 80%
What is hepatitis B&D?
- HBV ⇒ double-stranded DNA hepadnavirus
- Transmitted via sexual contact, blood and vertical transmission (from mother to baby) - HDV ⇒ single-stranded RNA virus coated with HbsAg. Defective virus (requires hepatitis B surface antigen to complete its replication and transmission cycle), that may only co-infect with HBV or superinfect people who are already carriers of HBV
- Chronic Hep B patient with flare up → suspect Hep D superinfection
What are the risk factors for hep B&D?
IV drug use, unscreened blood products, infants of HbeAg-positive mothers, sexual contact with HBV carriers, Genetic factors are associated with varying rates of viral clearance
Summarise the epidemiology of viral hepatitis B&D
- Common
- 1-2 million deaths annually
- Common in Southeast Asia, Africa and Mediterranean countries
- HDV is also found worldwide
What are the presenting symptoms of viral hepatitis B&D?
- Incubation period: 3-6 months
- 1-2 week prodrome consisting of:
- Malaise
- Headache
- Anorexia
- Nausea and vomiting
- Diarrhoea
- RUQ pain
- Serum-sickness type illness may develop (e.g. fever, arthralgia, polyarthritis, urticaria, maculopapular rash) - Jaundice then develops with dark urine and pale stools
- Recovery usually within 4-8 weeks
1% develop fulminant liver failure - Chronic carriage may be diagnosed after routine LFT testing or if cirrhosis or decompensation develops
What signs of viral hepatitis B&D can be found on physical examination
- Acute
- Jaundice
- Pyrexia
- Tender hepatomegaly
- Splenomegaly
- Cervical lymphadneopathy (in 10-20% of patients)
- Occasionally: urticaria and maculopapular rash - Chronic
- May be no findings
- May have signs of chronic liver disease or decompensation
What investigations are used to diagnose/ monitor hep B&D?
*Viral Serology
1. Acute HBV → HBsAg positive + IgM anti-HBcAg
- HBsAg is first marker to appear and causes production of anti-HBs.
2. Chronic HBV → HBsAg positive + IgG anti-HBcAg. May be HbeAg positive or negative.
3. HBV Cleared → anti-HbsAg antibody positive + IgG anti-HBcAg
- HbsAg positive indicates acute or chronic infection (ie. still have it). Anti-HbsAg antibody positive indicates immunity through previous immunisation or disease (ie. cleared).
4. Vaccinated against HBV → anti-HbsAg antibody positive (everything else negative, won’t have IgG antibody)
- Can only get antibodies against HbcAg if had infection, not with vaccination
5. HBeAg → marker of infectivity (higher = more infectious)
6. HDV Infection → PCR used for detection
*LFTs → raised AST, ALT, ALP, Bilirubin
*High PT in severe disease
1. PT = sensitive marker of significant liver damage
