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
How is hep B&D managed?
- Acute HBV → supportive
- Chronic HBV → interferon α (antiviral)
- Hepatitis B Immunisation
- Screen for HIV
- Prevention → blood screening, safe sex, instrument sterilisation
- Notifiable Disease
What complications may arise from hep B&D?
- 1% get fulminant hepatic failure
- Chronic HBV infection (10% of adults, much higher in neonates)
- Cirrhosis
- Hepatocellular carcinoma (HCC)
- Extrahepatic immune complex disorders (e.g. glomerulonephritis, polyarteritis nodosa)
- Superinfection with HDV may lead to acute liver failure or more rapidly progressive disease
Summarise the prognosis of patients with viral hepatitis B&D
- Adults: 10% of infections become chronic
- Of the chronic infections, 20-30% will develop cirrhosis
What is viral hepatitis C?
- Hepatitis caused by infection with hepatitis C virus (HCV), often following a chronic course (in 80% of cases)
- HCV ⇒ small, enveloped, single-stranded RNA virus
- Parenteral Transmission → sexual transmission and vertical transmission
What are the 2 types of HepC?
Acute <6 months, Chronic >6 months
- Most common type of hepatitis to become chronic
What patients are at high risk of HepC?
IV drug users, needlestick injury (health care workers), blood transfusion (esp. before 1992)
Describe the pathology of hepatitis C
- The virus is not thought to be directly hepatotoxic
- It is the humoral and cell-mediated responses to the viral infection that leads to hepatic inflammation and necrosis
- Liver biopsy shows:
- Chronic hepatitis
- Lymphoid follicles in portal tracts
- Fatty change
- Cirrhosis may be present
Summarise the epidemiology of viral hepatitis C
- COMMON
- Different genotypes of HCV have different geographical prevalence
What are the presenting symptoms of hep C?
- 90% of acute infections are ASYMPTOMATIC
- 10% become jaundiced with mild flu-like illness
- May be diagnosed after incidental abnormal LFT or in older patients with complications of cirrhosis
What are signs of hep C can be found on physical examination?
- ognise the signs of viral hepatitis on physical examination
May be NO SIGNS - There may be signs of chronic liver disease (if long-standing HCV infection)
- Extra-hepatic manifestations (rare) include:
- Skin rash
- Renal dysfunction (due to glomerulonephritis)
What investigations are used to diagnose/ monitor viral hepatitis C?
- HCV Serology → anti-HCV antibodies (IgM = acute, IgG = past exposure or chronic)
- RT-PCR → detection of HCV
- LFTs
- Liver Biopsy → assess degree of inflammation and liver damage. Useful for diagnosing cirrhosis.
How is HepC managed?
- Medical Treatment (Antivirals) → interferon α or ribavirin
- Needed for acute and chronic Hep C - Screen for HIV
- Prevention → screen blood, blood products and organ donors. Instrument sterilisation.
- No vaccine available for HCV
What complications may arise from viral hepC?
- Fulminant hepatic failure
- Chronic carriage of HCV
- Hepatocellular carcinoma
- Less common: porphyria cutanea tarda, cryoglobulinaemia, glomerulonephritis
Summarise the prognosis for patients with viral hepatitis C
- 80% of exposed will progress to chronic carriage
- Of these, 20-30% will develop cirrhosis over 10-20 years
