Organophosphate/ Insecticide Poisoning

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

  1. Nausea
  2. Vomiting
  3. Abdominal cramps
  4. Increased urinary frequency;
  5. Urinary and fecal incontinence
  6. Increased bronchial secretions
  7. Cough
  8. Dyspnoea
  9. Sweating
  10. Salivation
  11. Miosis
  12. Blurred vision
  13. Lacrimation
  14. Bradycardia
  15. Hypotension, and
  16. Pulmonary oedema may occur

Nicotinic effects

  1. Twitching
  2. Weakness
  3. Hypertension
  4. Tachycardia
  5. Paralysis in severe cases

CNS effects

  1. Anxiety,
  2. Restlessness
  3. Tremor
  4. Confusion
  5. Weakness
  6. Seizure
  7. 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.
  1. Treat seizures with intravenous diazepam 10 mg stat