Paper I
2023 March (Supplementary) (2010 Scheme) · 40 marks · 120 min

Question

A farmer was brought to the emergency department of the hospital presenting with lacrimation, salivation, sweating and breathlessness. O/E he is having miosis, blurring of vision, bronchospasm with copious trachea-bronchial secretions with BP- 100/60mmHg and PR-60/min. He gives history of spraying a strong insecticide in his agricultural field. (

  • (a) What is the likely diagnosis ( 1 mark(s)
  • (b) Briefly outline the general measures of management ( 2 mark(s)
  • (c) Discuss in detail the drugs used to manage this condition with its rationale for use 3 mark(s)
Q26 marksEssays

Answer

a) Diagnosis Organophosphate (insecticide) poisoning — the muscarinic toxidrome (lacrimation, salivation, sweating, miosis, bronchorrhoea, bronchospasm, bradycardia) following occupational insecticide spray exposure is classic.

b) General measures of management

  • Remove the patient from the contaminated area, remove and discard contaminated clothing
  • Decontaminate skin (wash thoroughly with soap and water) to halt continued absorption
  • Maintain airway, breathing, and circulation — suction copious secretions, give oxygen, ventilatory support if needed
  • Continuous monitoring of vitals and pupil size to titrate antidote therapy

c) Drugs used, with rationale

  • Atropine — competitively blocks muscarinic receptors, reversing bronchorrhoea, bronchospasm, bradycardia, and excessive secretions; titrated to effect (drying of secretions), often requiring large repeated doses. Does not reverse nicotinic effects (muscle weakness/fasciculations).
  • Pralidoxime (2-PAM) — a cholinesterase reactivator that reverses both muscarinic and nicotinic effects by displacing the organophosphate from acetylcholinesterase, but only if given before the enzyme-organophosphate complex “ages” (becomes irreversibly bound) — most effective when given early, alongside atropine.
  • Diazepam — controls seizures/agitation and has been shown to reduce mortality when given alongside atropine and pralidoxime.

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