Introduction
Organophosphates poisoning causes irreversibly inhibition of acetylcholinesterase leading to accumulation of acetylcholine at muscarinic and nicotinic synapses and in the CNS.
Organophosphates are absorbed through the skin, lungs, and gastrointestinal tract and are distributed widely in tissues.
Elimination is slow- by hepatic metabolism
Clinical features of organophosphate/ Insecticide Poisoning
Onset is usually between 30 minutes -2 hours after exposure
Muscarinic effects
- Nausea
- Vomiting
- Abdominal cramps
- Increased urinary frequency;
- Urinary and fecal incontinence
- Increased bronchial secretions
- Cough
- Dyspnoea
- Sweating
- Salivation
- Miosis
- Blurred vision
- Lacrimation
- Bradycardia
- Hypotension, and
- Pulmonary oedema may occur
Nicotinic effects
- Twitching
- Weakness
- Hypertension
- Tachycardia
- Paralysis in severe cases
CNS effects
- Anxiety,
- Restlessness
- Tremor
- Confusion
- Weakness
- Seizure
- Coma
Treatment for organophosphate/ insecticide Poisoning
Non-drug treatment
- Remove contaminated clothing
- Wash skin with soap and water
- Ventilatory support
Drug treatment
1. Oxygen administration
2. Atropine (Effective for muscarinic symptoms)
Adult:
- 0.5-2 mg intravenously every
5-15 minutes until bronchial and other secretions have dried
Child:
- 20 micrograms/kg (maximum 2 mg) intramuscularly or intravenously depending on the severity of poisoning, every 5- 10 minutes until the skin becomes flushed and dry, pupils dilate and tachycardia develops.
- Treat seizures with intravenous diazepam 10 mg stat