Organophosphate poisoning is poisoning due to organophosphates (OPs).Organophosphate poisoning occurs most commonly as a suicide attempt in farming areas and less commonly by accident. This mostly occurs in developing world. Organophosphates are chemicals in insecticide used extensively in agriculture. When people, such as agricultural workers, are exposed to large quantities of organophosphates, these chemicals can be harmful.
Types of organophosphate insecticides
Danger poison sign post pic
Route of absorption/poisoning;
ingestion(accidental or suicidal)
injection (intramascular or intravenous)
Organophosphate are absorbed through the skin lungs & GI tract and distributed widely in tissues and are slowly eliminated in hepatic metabolism.The principal effect is inhibition of cholinesterase enzymes, particularly acetylcholinesterase (AChE). This leads to accumulation of acetylcholine at;
Muscarinic receptors- in cholinergic receptor cell.
Nicotinic receptors – in skeletal neuromuscular junction and autonomic ganglia.
centraL nervous system(CNS).
1.There is always history of;
NB: Features of intoxication are usually delayed i.e. because the poison requires biotransformation to become active.
3.Muscarinic effects of Poisoning are characterized by;
Respiratory failure is worsened/exacerbated by development of rhinorrhoea and pulmonary Oedema
Central Nervous system
This occurs in severe poisoning and features include;
loss of memory
8.Organophosphate induced neuropathy
Starts two weeks or more after exposure
Occurs due to degeneration of mylenated motor & sensory fibres
1.Exposure is confirmed by measurement of plasma(butyrycholinesterase) or red blood cell cholisterase activity. These correlate poorly with the severity of clinical features, although values are usually less than 10% in severe poisoning,20%-50% in moderate poisoning and > 50% in subclinical poisoning.