Viral hepatitis A and E

Question 1

definition of viral hepatitis A and E

Answer 1

hepatitis caused by the RNA viruses:

• hep A (HAV)
• hep B (HEV)

follow acute course w/o progression to chronic carriage

Question 2

structure of HAV and HEV

Answer 2

HAV - picornavirus

HEV - calicivirus

both are small non-enveloped single stranded linear RNA virus, approx 7500 nucleotides

faecal oral or shellfish transmission

Question 3

aetiology of viral hep A and E

Answer 3

replicate in the hepatocutes and secreted into the bile

immune response - CD8+ T cells and NKC= liver inflammation and hepatocyte necrosis

Question 4

histology of hepatitis A and E

Answer 4

inflammatory cell infiltration (neutrophils, macrophages, eosinophils and lymphocytes) of the portal tracts

zone 3 necrosis

bile duct proliferation

Question 5

epidemiology of hep A

Answer 5

endemic in developing world

infection occurs subclinically

in developed world better sanitation = lower seroprevalence, age of exposure increased = more likely to be symptomatic

annual UK incidence is 5000 cases - seroprevalence is approx 5%

most infections are in childhood

Question 6

epidemiology of HEV

Answer 6

endemic in Asia, Africa and central America, indochina

more common in older men

more common than HAV in UK

associated with pigs

Question 7

sx of Hep A and E

Answer 7

incubation period 3-6wks

prodromal period:

• malaise
• anorexia (distaste for cigarettes in smokers)
• fever
• nausea
• vomiting
• arthralgia

hepatitis

• dark urine, pale stools and jaundice lasting 3wks
• occaisionally itching and jaundice last severeal weeks in HAV - cholestatic hepatitis

Question 8

signs of hep A and E

Answer 8

pyrexia

jaundice

tender hepatomegaly

adenopathy

spleen may be palpable

absence of stigmata of chronic liver disease (although may have transient spider naevi)

Question 9

Ix for hep A and E

Answer 9

bloods:

• LFT
  
  • v high AST and ALT 22-40days post exposure
  • high BR and ALP
• high ESR
• in severe - low albumin, high plts

viral serology have to do for B and C too to exclude

urinalysis - +ve BR, high urobilinogen

Question 10

viral serology for hep A

Answer 10

anti-HAV IgM (in acute illness from day 25, disappearing after 3-5mo)

anti-HAV IgG (recovery phase and lifelong persistence)

Question 11

viral serology for hep E

Answer 11

antu-HEV IgM - high 1-4wks after onset

anti-HEV IgG

Question 12

Mx of viral hep A and E

Answer 12

bed rest and symptomatic - antipyretics, antiemetics

colestyramine for severe pruritus

avoid alcohol

rare - INF-a for fulminant hepatitis

Question 13

prevention and control of Hep A and E

Answer 13

public health

• safe water
• sanitisation
• food hygiene standards
• notifyable disease
• personal hygiene and dietary precautions when travel

immunisation - HAV

Question 14

immunisation for HAV

Answer 14

passive with IM human Ig only effective for short period

active with attenuated HAV:

• safe and effective immunity for:
  
  • people travelling to endemic areas,
  • high risk individuals (residents of institutions)
• 1 IM injection lasts 1yr
• 20yes if booster at 6-12mo

Question 15

complications of hep a and e

Answer 15

fulminant hepatic failure develops in 0.1% of HAV, and 1-2% of HEV, but up to 20% in pregnancy

cholestatic hepatitis with prolonged jaundice and pruritis - after HAV

post-hepatitis syndrome - continued malaise for weeks to months

Question 16

Px of hep A and E

Answer 16

recovery usually within 3-6wks

occaisionally relapse in recovery

no chronic sequelae

fulminent hepatic failure - 80% mortality