VPT 421: Veterinary Toxicology (2+0)

PATHOLOGICAL EVIDENCES

• Gross changes observed during post mortem or on histopathological examination of tissue samples may provide evidence.
• More characteristic lesions are found in chronic poisoning.
• The pathological changes in live animal that may be of use include discolouration of the skin and mucous membrane.
• The colour of blood also gives an indication of the poison to be suspected – cherry red colour in carbon monoxide poisoning, chocolate brown colour in nitrate, nitrite and chlorate poisoning.
• The odour, nature and colour of gastrointestinal contents also provide valuable information.
• The odour produced by toxicants that give an evidence for diagnosis of poisoning include:
  • bitter almond for cyanides
  • garlic for phosphorus
  • phenolic for phenols and phenolic compounds
  • mouse like for hemlock
  • acetaldehyde for metaldehyde
• The colour of the gastrointestinal tract contents of interest include greenish blue for copper sulphate, yellow to orange green colour for chromium salts, yellow for nitric and picric acids and black for corrosive acids like sulphuric acid.
• Hepatic lesions are produced by such diverse materials as antimony, arsenic, boric acid, iron, lead, phosphorus, selenium, thallium, chloroform, carbon tetrachloride etc.
• Renal lesions are produced by irritant or otherwise nephrotoxic agents like mercury, lead, ochrotoxin, citrinin, sulphonamides etc.
• The presence of flakes of paint, leaves, twigs etc. in the gastrointestinal tract will give an indication for the poison to be suspected.

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