Infections

Question 1

Infections of the hepatobiliary system

Answer 1

1. Non-viral
   - Bacterial - pyogenic - E. coli, Klebsiella
   - TB - miliary
   - Amoebic abscess - Entameba histolytica
   - Parasitic/Helminthis
2. Viral
   - Systemic viral inf - EBV, CMV, rubella, adenovirus, enterovirus
   - Hepatotropic viruses

Question 2

Features of Hep A

Answer 2

• acute & fulminant hepatitis
• infectious, short incubation (2-6w)
• faecal-oral transmission (shellfish, water)
• diagnosis: IgM-HAV

Question 3

Features of Hep E

Answer 3

• acute hepatitis
• short incubation (35-40d)
• faecal-oral transmission, water-borne, zoonotic
• diagnosis: anti-HEV
• high fatality in pregnant women
• self limiting

Question 4

Features of Hep B

Answer 4

• acute, fulminant, chronic hepatitis
• long incubation (2-26w)
• blood, vertical (perinatal) transmission
• can cause acute GN, vasculitis due to circulating immune complexes
• diagnosis: anti-HBs, HBV DNA

Question 5

Features of Hep C

Answer 5

• acute (subclinical), chronic hepatitis
• long incubation (4-26w)
• blood transmission
• inherently unstable due to low fidelity of RNA polymerase - ineffective immunity conferred by IgG after an active infection - persistent infection, chronic hepatitis
• diagnosis: HCV RNA

Question 6

Features of Hep D

Answer 6

• defective RNA, req HBV for its replication
• HDV RNA coated with HBsAg
• aggravates HBV infections, co-infection, or superinfection
• diagnosis: anti-delta IgM

Question 7

Features of acute viral hepatitis (8)

Answer 7

1. Diffuse hepatocellular injury & lobular disarray
2. Focal necrosis, Councilman bodies (round red lobules - apoptotic bodies)
3. Inflammatory infiltrate in portal tracts - may spill over into adj parenchyma - apoptosis of periportal hepatocytes (interface hepatitis)
4. Kupffer cell hypertrophy, & hyperplasia + lipofuscin due to phagocytosis of debris
5. Cholestasis
6. Hepatocyte regeneration
7. Groundglass hepatocytes (only HBV)
8. Bridging necrosis, piecemeal necrosis

Question 8

Features of chronic hepatitis

Answer 8

• evidence of ongoing hepatic disease for >6m w histologically documented inflammation & necrosis
  1. Hepatocyte injury & necrosis
  2. Portal inflammation - interface hepatitis, bridging inflammation, necrosis
  3. Fibrosis - periportal, bridging fibrous septa

Question 9

Causes of chronic hepatitis

Answer 9

1. Chronic viral infection
2. Alcoholic liver disease
3. Metabolic
4. Autoimmune
5. Drug-induced