Org A No Phosphorus Poisoning

Organophosphorus poisoning ?? Blessing to developing nations. -Common poisoning agent •Suicidal •Accidental •Homicidal -300000 people die every year

Pharmacology

• OPs are highly lipid soluble • Primary target: “Acetyle choline esterase” • Inhibit AChE: increases Acetyl choline at cholinoceptors • Increased acetyle choline act on – Muscarinic Nicotinic CNS synapses

Pharmacology 3 types of choline esterase enzyme inhibitors  Simple alcohol bearing quaternary ammonium group e.g. edrophonium  Carbonic acid esters of alcohol e.g. carbamate (Baygon)  Organic acid derivatives of phosphoric acid e.g. all OPS

Clinical features

• Depends upon principle site of action • Usually develops over 15mins-2hrs

A: Muscarinic effect:

• Rhinorrhoea,bronchorrhoea,bronchconstri ction,wheezing,pulmonary edema • GI symptoms: salivation,nausea,vomiting,abd cramps,tenismus,diarrhoea • CVS:Bradycardia,Hypotension • Urogenital: Urinary incontinence and frequency • Eyes: constrited pupils,blurred

Clinical features B: Nicotinic Features: • Muscle fasiculation,weakness,cramps,paralysi s • Respiratory muscle weakness and paralysis • Ocular,bulbar.neck,proximal muscle of limb paresis C: CNS effects: Anxiety,restlesness,ataxia,insomnia,co

Diagnosis  History  Signs and symptoms  Charcteristic smell from mouth,cloths and gastric lavage  Atropin test: 0.6-3mg i.v ;look for signs of atropinisation  Estimation of Acetyl choline esterase level in blood < 50% of normal (3000-6000IU/lt)

Management Non Pharmacological  ABC  Removal of soiled clothes  Thorough cleaning of whole body with soap water  Gastric lavage till returning fluid is clear  Airway clearing  If needed intubation and ventilatory support

Management

Pharmacological management: Atropin Sulphate: start with 0.6mg3mg i.v. and access every 5-15 mins for signs of atropinisation Clear chest on auscultation with no wheezes Heart rate >100 Pupil no longer pin point Dry axilla Systolic pressure>90 mm of Hg (Over atropinisation leads to fever dellirium,Psychosis)

Management contd……

OXIMES: • Pralidoxime chloride(PAM) • -30mg/kg loading over 10-20mins followed by 10mg/kg i.v.6-8 hrly for at least 48 hrs (not useful for carbamate poisoning)

At ward daily assess for • Consciousness • Pulse/HR • Blood Pressure • Pupil • Muscle power • Dryness of lungs

Complications Acute: • Aspiration Pneumonia • Pulmonary edema • ARDS • Acute pancreatitis • Hypoglycemia • Lactic acidosis • Acute renal failure • Cardiac arrhythmiasbradycardia,tachycardia,AV dissociation,Torsades de pontis

Complications Chronic: • Intermediate syndrome • Delayed neuropathy • Depression