Organophosphorus Compounds Poisoning.
- Organophosphorus compounds are commonly used as "Insecticides." the common examples are, Malathion, Parathion, Diazinon, Fenthione etc.
- MOA: They act by irreversible inhibition of enzyme "Acetyl Choline Esterase", by causing permanent destruction of the enzyme structure the compounds set free Ach (Acetyl Choline) causing poisoning.
- Most of the times the poisoning is fatal one leading to death.
Modes:
- Physical Contact.
- Inhalation.
- Ingestion.
Causes:
- Occupational: Persons coming in contact with insecticides during their daily work. e.g. Farmers, Factory labors.
- Accidental: Accidental consumption or inhalation of household insecticides.
- Intentional: Homicide or Suicide.
Symptoms:
- The OPCs increase concentration of Ach and hence their effects can be categorized into two Muscarinic Effects and Nicotinic Effects.
- Here we are going to see effects for ingestion, inhalation and contact poisoning.
A) Ingestion Muscarinic Symptoms:
- Bronchospasm(wheezing) •
- Muscle weakness•
- Bronchorrhoea •
- Fasciculation•
- Productive cough•
- Dyspnoea •
- Paralysis•
- Hypotension •
- Muscle twitching•
- Bradycardia•
- Cardiac arrhythmia•
- Diarrhea•
- Vomiting•
- Salaivation•
- Tenesmus•
- Miosis•
- Lacrimation•
- Blurred vision
B) Inhalation Eye contact Symptoms.
- Cough
- Irritation
- Difficulty in breathing
- Pain
- Bronchitis
- Lacrimation
- Pneumonia
- Miosis
- Blurring vision.
Treatment:
- Prompt hospitalization.
- Cleaning of organs came in contact with the poison with soap.
- Cleaning of nasal pharyngeal secretions by hand or by using suction pathway to clear the obstruction in airway.
- Patient is kept in prone position to aid breathing.
- Artificial respiration (Endotracheal Intubation) is given immediately to cover respiratory depression which is major cause of death during OPC poisoning.
- Gastric lavage if poison is ingested, within two hours to remove unabsorbed poison.
- Antidote: "Atropine" is given 1.8-3.0 mg in fast iv bolus. ( Dose is titrated after checking the major symptoms after 3 to 5 minutes.
- Enzyme Reactivators: Pralidoxime,/ Obidoxime (Reactivate is phosphorylated enzyme) is given to reactivate the enzyme Ach Esterase.
- Symptomatic treatment.