Organophosphorus poisioning.pptx

organophosphorus ppt for undergraduates

1. ORGANOPHOSPHORUS POISONING Presented by- DR. Deepak Choudhary

2. Introduction OPCs are one of the most common cause of self-poisoning seen in India. They are used as insecticides, herbicides, antihelminthics , ophthalmic agents, in chemical industry, and as nerve gas in chemical warfare. Common OPCs are- ọ Parathion ọ Paraoxon ọ Chlorthion ọ Diazinon ọ Malathion ọ Phosdrin ọ HETP( Hexaethyl tetraphosphate) ọ TEPP(Tetraethyl pyrophosphate)

3. CASE PRESENTATION A 45 year old farmer presents to the casualty with diarrhoea,miosis and altered sensorium. His attendent reveals that he was spraying insecticide prior to the day in his field and from then he feels nausea, fatigueness . A 25 year old woman, who was admitted with suicuidal rodenticide ingestion presents miosis, urinary incontinence and cramps.

4. MECHANISM OF ACTION

5. SIGNS AND SYMPTOMS

6. Manifestation of OP Poisoning 1. Acute poisoning- It includes muscle fasciculations,cramps,twitching and weakness.It also involves CNS effects like dizziness,headache etc. 2. Intermediate Syndrome-It occurs 1 to 5 days after the exposure. It includes paralysis of neck flexors and respiratory muscle weakness. 3. Chronic toxicity- It causes symmetrical sensorineural axonopathy. 4. OP induced delayed neuropathy - It involves extrapyramidial symptoms and peripheral neuropathy.

7. Fatal dose Malathion and diazinon 1 g. Parathion: 175 mg. TEPP: 100 mg. HETP: 350 mg. Fatal period: Usually within 24 h in untreated cases and within 10 days in treated cases, if unsuccessful.

8. LABORATORY DIAGNOSIS The diagnosis of OPC poisoning is made primarily based on the history and a combination of clinical features, including the typical odor of the insecticide. The essential finding in laboratory diagnosis is depression of cholinesterase activity . In acute poisoning, signs and symptoms generally occur when > 50% of cholinesterase is inhibited. RBC (true) cholinesterase: It is found in the CNS gray matter, RBCs and motor end plate. → Plasma (pseudo or butyryl) cholinesterase: It is found in the CNS white matter, plasma, liver, pancreas and heart. RBC cholinesterase is considered more accurate of the two; however, plasma cholinesterase activity is easier to assay and generally more readily available, but declines rapidly.

9. ECG changes i n OP poisoning include QT segment prolongation . ST segment elevation is also reported in few cases Oxygen saturation should also be measured continuously.

10. TREATMENT OF ORGANOPHOSPHORUS POISONING

11. Decontamination One of the most important initial approaches in this poisoning. It includes patient’s removal from exposure, stripped of his clothes and the skin flushed with water. Gastric lavage- only when patient gets stable. Via NG tube with 1: 5000 KMnO4 Activated charcoal in doses 1g/kg

12. At ropinization

13. Role of Pralidoxime (2 PAM) Reverses muscle weakness and cramps, convulsions or coma, especially if given rapidly. That means reverses nicotinic effects of OP poisoning. To be used within 48 hours DOSE- 1-2g IV( 20-40mg/kg) dissolved in 0.9% normal saline and may be repeated 1-2 hours later. If muscle weakness still not relieved , given again after 8 to 10 hours

14. Supportive care

15. Thank You