Postmortem Examination in Poisoning Cases

Diagnosis of poisoning is based on history, signs, tissue changes, and laboratory examinations. Giving your doctor a complete history is essential to help him/her make an accurate diagnosis.

Diagnosis of poisoning of the dead is done based on:

1. Clinical history 
2. PM appearance 
3. Laboratory analysis 

Postmortem examination can further be done based on: 

1. Experiment on animals with the extracted poison from the body. 
2. Moral and circumstantial evidence 

Postmortem Examination in Case of Poisoning

In case of Hospital stay and treatment

• If the dead were admitted to the hospital, then the first sample of gastric lavage should be collected. Similarly, if available, blood and urine samples should be collected and then sent to the Forensic Science lab.
• Maintain the record of drugs, medications which the victim had used.
• Vomitus stains on clothes, feces stains, poison stains, and vomit should be collected and sent for toxicological analysis.
• In physical assault and road accidents, blood is usually drained immediately on admission to the emergency room. Blood should be sent to the blood bank for ABO typing and Crossmatch. It should then be preserved in the blood bank for at least 2 weeks. The blood sample can further be used for toxicological analysis if required.

Postmortem appearance in Poisoning Cases

External Examination

1. Any abnormal smell from the body should be noted.

• Petroleum smell– Organophosphorus poisoning,
• Garlic smell– Phosphorus-containing poisons (Aluminum Phosphide, Arsenic)
• Bitter almond smell– Cyanide poisoning.

2. Stains- Clothes, corner areas in mouth, and other surfaces of the body can show marks of vomit, poison stains and marks of feces.

3. A careful examination from head to toe should be carried out for

• Head hair- Patchy hair loss on the scalp is seen in arsenic poisoning, which could be due to accidental exposure at work.
• Nails- Mees line can be seen in heavy metal poisoning.
• Skin pigmentation in case of Heavy metal poisoning.
• Icterus (technical term for jaundice) in case of Hepatotoxic poisons.

4. Other details include injuries that should be well documented like 

• Burns (chemical burns)
• Abrasion, bruises marks over the skin.
• In case of puncture marks on the skin, it should be surrounded 2cm the wound and sent to the Forensic Science lab.

5. Careful examination of accumulation of fluid or blood in the lower of the body should be done as it may indicate certain Poisons;

• Cherry red can be observed in Carbon monoxide poisoning,
• Bright red– Cyanide poisoning,
• Yellowish or brownish– Phosphorus poisoning.

Internal Examination

• The significance of internal examination in poisoning or toxin-related death is to exclude the natural disease processes. The autopsy of internal examination can also help to correlate the symptoms produced by the poison or toxins.
• The Colour of blood should be noted, which is cherry red in case of CO poisoning. Similarly, muscles and mucus membrane of the stomach also appear cherry red in case of CO poisoning. 
• A careful examination should be done for any evidence of inflammation, abnormal odor, stains, erosions, congestions, mucosal edema, ulcers, and perforations in case of irritant and corrosive poisons.

1. Tongue
2. Esophagus
3. Stomach

• The heart should be examined for signs of myocardial infarction, and Subendocardial hemorrhages can be seen in the case of As, P, Sb, and viper bites. Some drugs, such as Cocaine, can produce severe vasospasm, which causes death from myocardial infarction and arrhythmias.
• Lungs should be examined for signs of edema of the glottis, congestion of the mucous membrane of the trachea and bronchi. 
• Other organs such as the liver should be examined for signs of hepatitis (Enlarged, yellowish liver) caused by hepatotoxic poisons and kidney for nephrotoxic poisons. 
• At the end of the autopsy, the findings can be the cause of death but cannot be discovered to be a particular poison. For resolving the cause of death as poisoning, the poison or toxin should be present in the body beyond the Median Lethal dose. So, we can collect the samples from the body and send them for toxicological analysis.

Samples to be Collected for Laboratory Analysis

Samples collected for toxicological analysis in case oral ingestion are:

• Part of Stomach and its content.
• A piece of the liver.
• Part of Intestines. 
• Half side of each kidney.
• Blood in a vial.
• For toxicological analysis, visceral samples are stored or preserved in a saturated solution of Saline.

If the case is suspected of alcohol intoxication and carbon monoxide poisoning, collect a minimum of 10ml of blood and preserve it in sodium fluoride for alcohol analysis and carbon monoxide poisoning. The blood sample should be airtight with liquid paraffin without any preservatives.