op poisoning

Case Scenario

  • Patient: 4-year-old male child

  • History: Consumed unknown substance 1.5 hours ago

  • Symptoms:

    • 2 episodes of diarrhoea

    • Urinated on the way to the hospital

    • Sick looking with drooling saliva

    • Glasgow Coma Scale: E3 V4 M5 = 12

  • Examination Results:

    • Vital signs: HR 50/min, RR 60/min, Temp 98.7°F, BP 70/50 mm Hg, SpO2 93% on RA

    • Garlicky breath odor

    • Cardiovascular: S1, S2 heard

    • Respiratory: BAE +, basal crepitations on both sides

    • Abdominal: Soft and non-tender, no organomegaly

    • CNS: Miosis, non-reactive pupils

Introduction

  • Organophosphates: Insecticides/nerve agents affecting acetyl-cholinesterase.

  • Uses: Insecticides, petroleum additives, chemical warfare.

  • Carbamates: Another group affecting same site but with different mechanisms.

Objectives

  • Mode of Toxicity

  • Variability of Toxicity

  • Toxicokinetics

  • Toxicodynamics

  • Clinical Picture

  • Treatment and Prevention

Mode of Toxicity

  • Accidental Exposure:

    • Ingesting contaminated food or pesticide

    • Transdermal contact (e.g., malathion)

    • Occupational exposure in farming

  • Suicidal: Common poisoning by parathion

  • Homicidal: Rare cases observed.

Toxicokinetics

  • Absorption: Skin, GIT, respiratory system.

  • Distribution: Mostly water soluble; few lipid soluble.

  • Metabolism: Some metabolites are more toxic.

  • Excretion: Mostly in urine.

Toxicodynamics

  • Inhibition of acetylcholinesterase increases acetylcholine (ACh) at nerve endings, leading to adverse effects.

Clinical Features

  1. Acute Organophosphate Poisoning:

    • Muscarinic effects

    • Nicotinic effects

    • CNS effects

  2. Intermediate Syndrome (occurs 24-96 hours post-exposure)

  3. Delayed Neuropathy (OPIDP)

  4. Neuro-psychiatric disorder (COPIND)

Management

  • Immediate Protocol:

    • Assess and record Glasgow Coma Scale and vital signs.

    • Patient positioning: Left lateral position.

    • Oxygen administration; intubate if necessary.

  • Atropine: 0.05mg/kg in frequent boluses.

  • Oximes: Used in all OP poisoning cases except carbamates.

  • Decontamination: Remove clothing and scrub skin thoroughly.

Prevention Tips for Children

  • Do not leave containers open.

  • Do not transfer products between containers.

  • Keep labels intact on medications.

  • Avoid referring to medicine as sweets to discourage ingestion.