Page 12 of 33

FM13.15 | Agrochemical & Pesticide Poisoning — SDL Guide (Part 2)

Clinical Examination, Post-Mortem Findings and Medicolegal Documentation

Clinical examination approach in pesticide poisoning:

The clinical examination must serve two functions: emergency triage and medicolegal documentation. The first step is to identify the toxidrome — the constellation of signs that points to a pesticide class.

Cholinergic toxidrome (OP/carbamate): SLUDGE + BB + miosis + fasciculations. No other toxidrome produces this combination.

Excitatory toxidrome (organochlorine/pyrethroid): tremor, myoclonus, seizures; hyperreflexia; NO cholinergic signs.

No initial toxidrome (paraquat, phosphide): patient may appear deceptively well initially — this is the most dangerous pattern. GI symptoms (nausea, vomiting, mouth/throat pain) without major CNS or autonomic signs in the first hours.

History documentation:
- Time of exposure/ingestion
- Product name (ask family to bring the container — the label specifies the active ingredient class)
- Route (ingestion/inhalation/skin)
- Quantity ingested
- Any first aid given
- Circumstances (occupational, suicidal, accidental, homicidal)

Key investigations to document:
- RBC AChE activity (cholinesterase level) — confirms OP/carbamate exposure; depressed AChE (<50% of baseline) = significant exposure. Important: baseline varies between labs — compare with the lower limit of normal, not an individual baseline.
- ECG (QTc prolongation in OP/carbamate and phosphide; arrhythmia)
- ABG (metabolic acidosis in phosphide, paraquat)
- Chest X-ray (OP pulmonary oedema; paraquat alveolitis on serial films)

Post-mortem findings:
- OP/carbamate: cholinergic excess — pulmonary oedema (most consistent finding), bronchial hypersecretion, petechial haemorrhages; garlic odour (organophosphates); reduced AChE in PM blood
- Paraquat: fibrosing alveolitis — honeycombing, consolidation on X-ray; PM lung shows typical proliferative fibrosis histologically
- AlP: gastric burns, pericardial haemorrhage, myocardial necrosis; phosphine detected by Drager tube/chemical test in headspace gas

Medicolegal documentation:
Samples: gastric contents (most important — snap-freeze for organophosphate/pyrethroid GC-MS), blood (fluoride-oxalate), urine, liver (PM). The empty bottle/packet should be seized and documented as exhibiting material.

Provided image

Medicolegal Inference and Statutory Framework

The vast majority of pesticide poisoning deaths in India are suicides, but homicidal administration is documented — particularly organophosphate added to food or drink, and paraquat ingestion after domestic disputes (its presence in food is not easily detected by taste). The forensic medicine specialist's MLR must:

1. State the cause of death (e.g., 'Acute organophosphate poisoning causing respiratory failure and multi-organ failure')
2. Describe the route and manner (ingestion; suicidal/accidental/homicidal — based on circumstances)
3. Confirm the diagnosis (analytical toxicology findings, AChE activity)
4. Document the exhibit chain of custody

Treatment summary for examination recall:

Agent	Antidote/key treatment	CONTRAINDICATION
Organophosphate	Atropine (no dose limit) + PAM within 24–48 h	PAM after ageing (>48 h — of no benefit)
Carbamate	Atropine only	PAM (not needed; may worsen in some carbamates)
Paraquat	Supportive only; avoid O₂	OXYGEN — contraindicated
AlP/ZnP	Supportive only	No antidote exists
Organochlorine	Benzodiazepines for seizures	—
Pyrethroid	Benzodiazepines, supportive	—

Statutory context:
- IPC §302/304 (murder/culpable homicide) if homicidal
- IPC §304A (negligence) if occupational health breach
- Insecticides Act 1968: regulates manufacture, sale, and use of pesticides in India; violation of storage/labelling norms by employers may constitute criminal negligence
- Environment Protection Act 1986: regulates organochlorine use; relevant if environmental contamination caused exposure

Emergency Management Flowchart for Organophosphate Poisoning