A 38-year-old farmer is brought to the emergency department with acute onset of miosis, muscle fasciculations, excessive salivation, and respiratory distress. He was found unconscious in his field after spraying pesticides. Which is the most common organophosphate compound responsible for poisoning cases in India?

Explanation

## Most Common Organophosphate Pesticide in India **High-Yield:** Monocrotophos is the single most common organophosphate pesticide involved in acute poisoning cases in India, accounting for approximately 40–50% of all organophosphate poisoning deaths in the country. ### Epidemiology in India **Key Point:** Monocrotophos is widely used in agricultural regions across India due to its low cost, ready availability, and broad-spectrum insecticidal activity. It is frequently used on cotton, vegetables, and pulses, making it accessible to rural populations. ### Comparison of Common Organophosphates in India | Compound | Toxicity | Common Use | Frequency in Poisoning | |----------|----------|-----------|------------------------| | **Monocrotophos** | High | Cotton, vegetables, pulses | **Most common (40–50%)** | | Parathion | Very high | Restricted use now | Declining | | Malathion | Low–moderate | Public health (DDT alternative) | Rare | | Dichlorvos | Moderate | Household, stored grain | Uncommon | ### Clinical Context **Clinical Pearl:** The classic presentation of organophosphate poisoning (SLUDGE syndrome: Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis) combined with miosis and muscle fasciculations is pathognomonic. Monocrotophos is the most likely culprit in an Indian agricultural setting. **Mnemonic:** **SLUDGE** — Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis (cholinergic crisis from acetylcholinesterase inhibition). ### Mechanism Organophosphates irreversibly inhibit acetylcholinesterase (AChE), leading to accumulation of acetylcholine at synapses and neuromuscular junctions, causing: - Muscarinic effects (miosis, salivation, bronchospasm, bradycardia) - Nicotinic effects (muscle fasciculations, paralysis) - CNS effects (seizures, coma) **Key Point:** Monocrotophos is a systemic organophosphate with high lipid solubility, allowing rapid absorption through skin, lungs, and GI tract — a major reason for its high lethality in accidental and intentional poisoning.