Viral Hepatitis Flashcards
What is hepatitis?
Refers to the inflammation of the liver
Can be from infectious causes:
- Hepatitis A-E viruses
- CMV, RBV, adenovirus
Also non-infectious:
- Medications
- Toxins
- Auto-immune disorders
What are the features of different hepatitis viruses? (type, chronicity, spread, vaccine)
HAV:
- Small, unenveloped, symmetrical RNA virus
- Acute only
- Faeco-oral route; uncooked shellfish = common cause
- Vaccine available
HEV:
- Small, unenveloped, RNA virus; Pig reservoir
- Acute mainly, chronic possible (e.g. if immunosuppressed)
- Faeco-oral route; water/food borne
- No vaccine in UK
HBV:
- Enveloped, double stranded DNA virus; replicating by reverse transcription
- Acute and chronic
- Blood/body fluids incl. unprotected sex, needle sharing and vertical transmission
- Vaccine available
HCV:
- Enveloped, single stranded RNA virus; Chimpanzee hosts
- Acute (25%) and chronic (75%)
- Blood/body fluids incl. unprotected sex, needle sharing and vertical transmission (but mostly needles)
- No vaccine
HDV:
- Enveloped particle, only able to propagate in the presence of HBV as a (co-infection or superinfection)
- Acute and chronic
- Blood/body fluids incl. unprotected sex, needle sharing and vertical transmission
- No vaccine
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What is the epidemiology of viral hepatitis?
HAV:
- Decreasing prevalence worldwide, most common in developing countries e.g. India, Pakistan, Bangladesh, Nepal; parts of Africa, South and Central America and the Middle East
HBV:
- Most common cause worldwide; c.1/350 in UK
- Vaccination has caused big declines
HCV:
- c.214,000/UK
- Numbers keep increasing
HDV:
- Numbers dropping as HBV numbers are too
HEV:
- Common worldwide with frequent outbreaks
How does HAV present?
Incubation period:
- 2-6wks
Prodrome:
- Mild flu-like symptoms (anorexia, nausea, fatigue, fatigue, malaise, joint pain)
- Smokers lose taste for tobacco
- Diarrhoea
Icteric (=jaundiced) phase:
- Dark urine (appears first)
- Pale stools (not always)
- Jaundice (70-85%)
- Abdo pain (40%)
- Prutiris
- Arthralgia + skin rash (less common, vasculitic appearance)
- Tender hepatomegaly, splenomegaly and lymphadenopathy
Younger children are more likely to have mild symptoms/be asymptomatic
Pregnant women are more likely to experience complications e.g. hepatic failure
Recovery can take up to 6/12
How does HBV present?
Incubation:
- 40-160 days
Acute:
- May be subclinical or with a mild flu-like illness (see hep A)
- Jaundice in 30-50%
- Decompensated liver disease is possible
Chronic:
- Many are healthy carriers
- Some have symptoms of fatigue, anorexia, nausea and RUQ pain
- Hepatocellular carcinoma and cirrhosis are common complications
How does HCV present?
Incubation:
- 6-7 weeks
Acute:
- Mostly asymptomatic
- Jaundice +/- deranged LFTs +/- anorexia, lethargy, abdo pain in 20-30%
Chronic:
- Persistently raised/fluctuating LFTs
- Often goes unrecognised for 10-20yrs and becomes an incidental finding
How does HDV present?
Co-infection (at same time) and superinfection (caught after) with HBV and HVD puts individuals at a greater likelihood of experiencing:
- Liver failure during acute infection
- Rapid progression to cirrhosis
- Increased risk of liver cancer
- Overall greater fatality rates
What initial blood tests might you do if you suspect viral hepatitis?
LFTs:
- ALT>AST = a general feature of hepatitis; will be at varying levels in each viral hepatitis at different points (e.g. chronically elevated enzymes in chronic HCV) but will help guide you towards using more specific blood tests
- Alk phos may be normal
- Bilirubin also rise (hence jaundice)
- Albumin may also be deranged as liver synthetic function is off
Clotting:
- INR, PT- severe prolongation might indicate (impending) acute liver failure
FBC, U+E, ferritin, lipids; serology for HIV or other viral causes of hepatitis
What are the specific tests required to diagnose viral hepatitis?
Viral serological testing
- Looks at the presence of a range of different antigens and antibodies/Ig depending on what cause is suspected and where in the timeline we are
What do serological tests show in HAV?
IgM HAV
- Presence indicates previous hep A or vaccine
- Indicates lasting immunity
What do serological tests show in HBV?
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HBsAg:
- HBV surface antigen - found on outer wall of envelope
- Presence indicates current infection
- Is the earliest detectable sign of the infection in your body (3-5wks post infection)
- If present for >6/12 = carrier status/chronic disease
- The vaccine involves injecting patients with HBsAG, so will be present just after vaccination
- Absence indicates you have never had HBV or you have had it and cleared it (including if you’ve been vaccinated)
HBeAg:
- HBV envelope-antigen - found between the surface and the core of HBV
- Presence indicates current infection AND that the virus is replicating (as is released only during replication) i.e. you are highly contagious, proportional to titre of HBeAG
- Usually present for 1.5-3/12 after acute illness
HBcAg:
- HBV core-antigen - found inside the core area
- Not free circulating itself as is encapsulated so not a good measure for viral presence
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HBsAb:
- HBV surface antibody
- Responsible for triggering initial immune response to HBV
- +ve in resolved infection AND in vaccination (as would have been produced in response to injected HBsAg) - therefore you need other viral markers to tell whether there is/has been an infection (as opposed to vaccination)
- Negative in chronic HBV infection
HBeAb:
- HBe ‘e’/envelope antibody
- Presence indicates your body is producing an immune response to HBV
- Also present in people recovering from acute hep B - here will have low/absent HBeAg
- If present in chronic hep B, indicates that only low levels of the virus are likely to be present in the blood
HBcAb:
- HB core antibody
- Used to help distinguish acute, chronic, past infections
- Acute infection = High IgM HBcAb (+ +ve HBsAg)
- Chronic infection = Low IgM HBcAb + high IgG HBcAb (+ +ve HBsAg)
- Past infection = Low IgM HBcAb + High IgG HBcAb (+ no HBsAg)
HBV DNA:
- Looks at the viral load - the viral copies in the blood stream
- Greater the viral load, the more active the infection
Order:
- Screen with - HBcAb (previous infection or vaccination?) + HBsAg (active infection?)
- If positive - HBeAg (how infective/much replication?) + HBV DNA (viral load)
Should also test for HCV and HDV serology to rule in/out co-infection
What do serological tests show in HCV?
HCV-RNA:
- Used to detect HCV in the blood
- Presence indicates active infection
Anti-HCV:
- Detects the presence of HCV antibodies
- Presence indicates that you have been exposed to HCV
HCV-viral load:
- Measures the number of viral RNA particles in the blood
Viral genotyping:
- There are 6x genotypes for HCV
- Most common in the UK is type 1
- Treatments differ between genotypes (and viral load, presence of cirrhosis, and prior treatment exposure etc)
What general advice should be given in hepatitis? (by subtype)
A+E:
- Advice about food + toilet hygiene
- Reassurance about the chronicity of the illness
- Avoid unprotected sexual intercourse (HAV can also be sexually transmitted e.g. rimming)
B+C:
- Avoid unprotected sexual intercourse of all types until they have become non-infectious or until their partners have received any available vaccines
- Explanation of their condition, emphasising long term implications for health + their partner; routes of transmission and abstaining from blood donation
Obtain info necessary for contact tracing
- Advice about vertical transmission
- Advice about needle use
Abstaining from alcohol and smoking until liver enzymes are normal
Advice about risks in pregnancy
What initial management might be indicated in viral hepatitis?
ABCDE:
- Are there any signs of decompensated liver disease that require hospitalisation?
Referral:
- Anyone with newly found biomarkers of acute infection needs a specialist/hepatologist/ID
Supportive: (this is generally indicated for uncomplicated HAV)
- Fluids
- Antiemetics
- Reassurance + advice
- Rest
Itching:
- Stay cool
- Wear loose clothing
- Avoid hot showers/baths
Vaccination:
- With hepatitis any available vaccine they are not infected with i.e. Hep A and B for someone with hep C - as co-infection increases risks of hepatic failure
- Same for close contacts of the affected
Stop any non-essential hepatotoxic medications
