Organophosphorous Poisoning

Setting: Agricultural poison, often accidental due to contact,inhalation or ingestion
symptom onset:most rapid-inhalation,least rapid-skin
sequence of effect:involuntary muscles&glands>voluntary muscles>vital brain centres
Respiratory symptoms may mimic asthma attack
Signs & symptoms occur when cholinesterase level drops to 30% of its normal activity
Victim: Agricultural workers, handlers of organophosphorous compounds
Clinical features: Often smell of organophosphorous compounds
Cholinergic effects: miosis+bradycardia+parasympathetic activation+increased secretion of glands+muscular contraction+urinary incontinence most often
Muscarinic effects: SLUDGE- 
Chromolacryorrhoea- porphyrinemia(SHEDDING OF RED TEARS) due to accumulation of porphyrins in the lacrymal gland


Cause of death:paralysis of respiratory muscle/failure of respiratory centre/intense bronchoconstriction
late death-due to ventricular arrhythmias(as long as 15 days after exposure/ingestion)


Diagnosis: Cholinesterase activity Plasma vs Red cell If that in plasma decreases,and red cell constant,implies exposure mild. If both affected southwards,severe form of exposure. In tissue samples at room temperature,cholinesterase activity can be assessed till 1-2 days,at temp 4-8 degrees,can be assessed even after months.

Clinical diagnosis: iv injection of 2 ml atropine relieves most symptoms,whereas in normal subjects it causes atropinization (mydriasis+cycloplegia+abolition of light reflex+tachycardia+sympathetic activation+decreased secretion of glands+voluntary muscle relaxation+sphincter tone rise+body temperature rise)

Treatment: Atropine 2-4 mg iv repeat every 10-15 minutes till patient stabilizes usual maint dose 40 mg/day max 1000 mg/day
Oximes: Pralidoxime