Category:Hepatitis, Bacterial

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Hepatitis, Bacterial

  • bacteria can enter the liver through a variety of routes
    • direct implantation
    • direct extension from disease in adjacent tissues of supportive peritonitis
    • haematogenously
      • via the umbilical vein from an infected umbilicus
      • via the portal vein in the alimentary tract
      • via the hepatic artery in bacteraemias and septicaemias
      • via the bile ducts
  • the liver may show microscopic evidence of involvement in a large variety of systemic infections
  • these can be accompanied by jaundice
  • the changes in the liver are diffuse with many small areas of necrosis surrounded by neutrophils and lymphocytes
    • eg Salmonellosis or Listeriosis


Bacillary Haemoglobinuria


Tyzzer's Disease



Leptospirosis

  • Leptospirosis icterohaemorrhagica - a septicaemic disease which affects the liver
  • puppies
  • Leptospirosis is an important spirochaetal group of diseases causing disease in animals and humans (zoonotic)
  • Transmission
    • via urine of affected animals
    • organisms can remain viable for weeks in damp conditions
  • method of action
    • cause anaemia via intravascular haemolysis
Clinical
  • fever
  • dehydration
  • haemorrhaging from the mucous membranes of the body
Diagnosis
  • dark field microscopy on fresh urine is best
Gross
  • widespread hameorrhages
  • icterus
  • pale foci in the liver (not always a constant finding)
  • subcapsular and cortical renal haemorrhages
Microscopically
  • foci of necrosis
  • dissociation of hepatocytes form each other (similar to post mortem change)
  • substantial haemosiderin in the Kuppfer cells (from the haemolysis)
  • need to use a silver stain or immunofluorescence to demonstrate the organisms in tissues

Salmonellosis

  • Salmonella dublin
  • calves
Clinical
Gross
  • severe, often haemorrhagic, inflammation in the ileum
  • paratyphoid nodules - pale foci of necrosis in the liver
Microscopically
  • foci of hepatocytic necrosis
  • mixed mononuclear inflammatory cell infiltrate

NB: small foci of hepatocytic necrosis are often found as incidental lesions at post mortem examination

Other bacteria causing liver lesions

Mycobacterium tuberculosis
  • in all species
  • causes granulomas
Actinobacillus equuli
  • foals
  • bacteria from the septicaemia localise in the liver and other tissues, including the kidney
Nocardia species
  • dogs
  • cause pyogranulomatous foci

Pages in category "Hepatitis, Bacterial"

The following 8 pages are in this category, out of 8 total.