Organophosphate poisoning is caused by insecticides and chemical weapons that inhibit cholinesterase, causing excess acetylcholine. It affects over 200,000 people annually and has acute cholinergic effects, intermediate syndrome 1-4 days later with respiratory muscle weakness, and sometimes delayed neuropathy weeks later. Treatment involves atropine to reverse cholinergic effects and pralidoxime to reactivate cholinesterase. Management also requires decontamination, supportive care, and monitoring for complications due to the risk of intermediate syndrome and delayed effects.

1. Shikha Pandey
Presented by:
Vikram Singh

2. Introduction
• Widely used insecticides throughout the
world, anti-cholinesterase agents
• kills an estimated 2,00,000 people every year
• Common cause of poisoning
• Example: Malathion, Parathion, Soman, Sarin,
Dichlorvos

3. Mechanism of toxicity
Reversibly / Irreversibly inhibits cholinesterase

4. Effectively absorbed by all routes
• Dermal / conjunctival
• Inhalational – during spraying
• Gastrointestinal Ingestion

5. Phases of OP poisoning
Acute cholinergic phase
 Intermediate syndrome
 Organophosphate-induced delayed
polyneuropathy (OPIDN)
– Onset, severity and duration of poisoning depend
on the route of exposure and agent involved

6. Acute cholinergic phase
• Starts within few minutes of exposure
• Nicotinic or muscarinic features may be present
• Vomiting and diarrhea, typical for oral ingestion
• Generalised flaccid paralysis affecting respiratory
and ocular muscles
• Other features may be extrapyramidal features,
pancreatitis, hepatic dysfunction and pyrexia

7. Muscarinic Nicotinic
Respiratory Bronchorrhea,
brohchoconstrition
Reduced ventilation
CVS bradycardia., hypotesion Tachycardia, hypertension
CNS Confusion -
Muscle - Fasciculation, paralysis
Temperature Fever -
Eyes Diplopia, Lacrimation, miosis
Abdomen Ileus, palpable bladder Vomiting, diarrhea
Mouth Dry Salivation
Skin Flushing, hot, dry Sweating
Complication seizures seizures

8. Contd…
• Muscarinic effectspnemonics “DUMBELLS”
• D-diarrhea
• U-urinary frequency
• M-miosis
• B-bradycardia, bronchorrea, bronchoconstriction
• E-emesis
• L-lacrimation
• S-salivation
• CNS effects
– Headache, altered consciousness, respiratory
failure, seizure

9. Intermediate syndrome
• In 20% case of OP poisoning
• Development of weakness of muscle rapidly
– Spreading from ocular muscle to head and neck,
proximal limbs and muscle of respiration may lead to
ventilatory failure
• After 1-4 days of exposure when symptoms/signs of acute
cholinergic syndrome are no longer obvious
• May last 2-3 weeks

10. Organophosphate-induced delayed
polyneuropathy
• Rare complication
• Occur 2-3 weeks after exposure
• Mixed sensory/motor polyneuropathy
• C/Fmuscle cramps followed by numbness and
paraesthesis flaccid paralysis of lower limbs
and subsequently upper limbs

11. Investigation
• Baseline investigation– creatinine,
electrolytes, RBS
• Cholinesterase level in serum- specific
• ECG to look for evidence of toxicity and to
monitor success of atropine therapy

12. Management
• General management
• Specific management

13. General management
• Universal precaution
• Maintenance of ABC
– Airway should be cleared of secretion
– High flow O2
– IV access
• Decontamination of skin
– Prevent further absorption
– Remove contaminated clothing and contact lenses
– Wash skin with soap and water and irrigate eye
• Gastric lavage and activated charcoal if within 2 hour

14. Specific management
• Atropine
– Anticholinergic
– Physiologically reverses the action of OP
– 0.6-2mg IV, repeated every 3-5 mins until secretions
controlled, skin is dry and there is sinus tachycardia
(atropinization)
– No effect on nicotinic receptors in autonomic
ganglia and neuromuscular junction

16. Contd…
• Pralidoxime should be administered 2gm i.v. over 4
minutes repeated 4-6 hourly to reverse or prevent
muscle weakness, convulsion or coma
• Reactivates AchE that has not undergone ageing
• Ventilatory support should be instituted
• Benzodiazepines may be used to reduce agitation and
fasciculation, treat convulsion and sedate patient

17. Ageing
DOC: Pralidoxime

18. Cont…
Intermediate syndrome
– No specific treatment
– Supportive care– maintenance of airway and
ventilation
Organophosphate-induced delayed
polyneuropathy
– No specific treatment
– Supportive care
– Regular physiotherapy– may limit deformity

19. Postmortem Findings
External
I. Kerosene like smell from nostrils and mouth
II. Cyanosis of lips, nose and fingers
III. Deep postmortem staining
IV. Congested face
V. Blood stained frothy discharge from nose
and mouth
NOTE: OP usually delays putrefaction

20. Postmortem Findings Cont’d
 Internal
I. Mucosa of stomach and intestine is
congested
II. Stomach contents may give kerosene-like
smell
III. Edematous respiratory passage (may also
contain frothy hemorrhagic exudates
IV. Edema and congestion of lungs
V. Brain edema
VI. Heart: soft and flabby

22. Medicolegal Aspects
 Accidental poisoning, Suicidal poisoning or Homicidal
poisoning
 Hospitalizing all symptomatic patients for at least 4-6 days
following resolution of symptoms, because of the risk of
development of respiratory depression or intermediate
syndrome after resolution of an acute crisis
 Informing Police
 The symptoms of OPC poisoning can mimic other
toxidromes and diseases. The clinician must keep in mind
that misdiagnosis is a potential medico-legal pitfall

23. References
• Nageshkumar G Rao, Textbook of Forencic Medicine and
Toxicology, 2 Edition
• http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.
1.1.430.4956&rep=rep1&type=pdf
• Davidson's Principles and Practice of Medicine 21 Edition
• Parveen Kumar and Michael Clark, Clinical Midicine, 8th
Edition
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC249339
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