Postmortem examination in case of poisoning

The following procedure is in addition to the procedures described under Autopsy procedure.

In our context, samples for toxicological analysis are collected in case

  • Frank case of poisoning
  • Suspicious deaths when no cause of death is found
  • Suspected poisoning from circumstantial evidence
  • Air crash (Captain and Co-pilot),
  • Drivers in case of road traffic accidents and pedestrians
  • Hospital deaths or death during surgery (to determine the level of drugs given at the hospital).

In case of Hospital stay and treatment

  • If the deceased was admitted in hospital then the 1st sample of gastric lavage should be collected, similarly blood and urine sample if available should be collected and sent to Forensic Science lab.
  • Vomits and vomitus stain over cloths should be collected and send for toxicological analysis.
  • In cases physical assault and road accidents, blood is usually drawn immediately on admission to the emergency room and sent to the blood bank for typing and cross-match; it should then be retained in the blood bank for at least 2 weeks. This sample can later be used for toxicological analysis if required.

External Examination:

  1. Any abnormal odor from the body should be noted
    • Petroleum – Organophosphorus poisoning,
    • Garlic – Phosphorus containing poisons (Aluminum Phosphide, Arsenic)
    • Bitter almond – Cyanide poisoning.
  2. Suspicious stains over the body and clothes should be collected and sent to Forensic lab.
  3. Careful head to toe examination is then carried out
    • Head hair
      • Patchy alopecia is seen in arsenic poisoning, which could be accidental exposure at work
    • Nails
      • Mees line in heavy metal poisoning
    • Skin pigmentation
      • Heavy metal poisoning
    • Icterus
      • Hepatotoxic poisons
  4. Any details regarding injuries should be well documented, including;
    • Burns (Chemical burns)
    • Puncture marks over the skin
    • (In case of puncture marks on skin, surrounding 2cm of skin should be excised and sent to Forensic Science lab)
  5. Careful examination of hypostasis should be done as it may indicate certain Poisons;
    • Cherry red – Carbon monoxide poisoning
    • Bright red – Cyanide poisoning
    • Yellowish or brownish – Phosphorus poisoning

Internal Examination

  • The importance of internal examination in case of poisoning or toxin related death is to rule out natural disease processes. The findings of internal examination can also make helps correlate the symptoms produced by the poison or toxins.
  • Colour of blood should be noted, which is cherry red in case of carbonmonoxide poisoning. Similarly muscles also appear cherry red in case of carbon monoxide poisoning.
  • In case of irritant and corrosive poisons, careful examination should be done to note for any abnormal smell, stains, congestions, mucosal edema, erosions, ulcers and perforations
    1. Tongue
    2. Esophagus
    3. Stomach
  • Heart should be examined for signs of myocardial infarction, even if the coronary arteries are patent. Some drugs such as Cocaine can cause severe vasospasm and cause death from myocardial infarction and arrhythmias.
  • Lungs should be examined for signs of edema.
  • Other organs such as liver should be examined for signs of hepatitis (Enlarged, yellowish liver).

At the end of autopsy, even after the above mentioned findings are present the cause of death cannot be ascertained to a particular poison. For determining the cause of death as poisoning, the poison or toxin should be present in the body beyond the Median Lethal dose. So, we should collect samples from the body and sent for toxicological analysis.

Samples to be collected:

Currently in our context following samples are collected for toxicological analysis in case oral ingestion

  • Stomach with its entire content
  • Piece of liver (200-300gms)
  • Half of each kidney
  • For toxicological analysis, visceral samples are preserved in saturated solution of Sodium Chloride (NaCl).

In suspected alcohol intoxication and carbon monoxide poisoning, at least 10ml of blood is collected (preserved in sodium fluoride for alcohol analysis and for carbon monoxide poisoning blood sample should be sealed with liquid paraffin without any preservatives)