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1 University College of Medical Sciences & GTB Hospital, Delhi POISONING AND TOXIC EXPOSURES – TYPES , DIAGNOSIS AND GENERAL PRINCIPLES OF MANAGEMENTDr. Neha KanojiaUniversity College of Medical Sciences & GTB Hospital, Delhi
2 What is a Poison ?“Poison is a substance ( solid/ liquid or gaseous ), which if introduced in the living body, or brought into contact with any part there of, will produce ill health or death, by its constitutional or local effects or both.”Ref- The Essentials of Forensic Medicine and ToxicologyDr. K. Reddy
3 Poisoning“The development of dose related adverse effects following exposure to chemicals, drugs or other xenobiotics.”Ref- The Essentials of Forensic Medicine and ToxicologyDr. K. Reddy
4 EPIDEMIOLOGY WHO (2004) - 3,46,000 deaths in a year d/t poisoning. In 2005 – In India 1,13,914 estimated cases of poisoning with insecticidesCommonest cause in INDIA – PesticidesReasons – Agriculture based economy- Easy availability pesticides- Poverty
5 Types of poisoningAcute poisoning – excessive single dose, or several smaller doses of a poison taken over a short interval of time.Chronic poisoning – smaller doses over a period of time, resulting in gradual worsening eg. Arsenic , Phosphorus , Antimony etc.
6 Nature of poisoningHomicidal – killing of a human being by another human being by administering poisonous substance deliberately.Suicidal – when a person administer poison himself to end his/ her life.Accidental – Eg. Household poisons- nail polish remover , acetone .Depilatories- Barium sulphide4. Occupational – in professional workers. Eg. insecticides, noxious fumes.
7 Classification of poisons According to the chief symptoms produced :-Corrosives SystemicIrritants MiscellaneousCorrosivesStrong acids- H2SO4 , HNO3 , HClStrong alkalis- Hydrates & Carbonates of Na+ , K+ & NH3Metallic salts – Zinc chloride, Ferric chloride, KCN , Silver nitrate, Copper sulphate.
12 Diagnosis of poisoning History – patientwitnessCircumstantional evidencesuicide notecontainers & potential toxins at scene ofdiscoveryPhysical examinationInvestigations-Biochemical investigations-ECG abnormalities-Radiology-Toxicologic screening
13 HistoryPatientIf person is conscious , & immediately brought to the ED, history may be relevantMostly patient estimates of drug/ nature of substance ingested are inaccurate.WitnessWhat substance/ substances ?What route/ routes ?What dose/ doses ?When and for how long?H /O psychiatric illness?
14 Circumstantial evidence Unconscious adultsEmpty drug containers/ wrappers /tablet neraby↓some sort of poisoningTablet particles staining mouth / clothingSuicide note↓Assumption of poisoning
15 Following conditions should arouse suspicion of poisoning :- Sudden appearance of symptoms after food or drink in an otherwise healthy personSymptoms – uniform in character, rapiditySudden onset delirium, paralysis, cyanosis, collapse etc.
16 Physical examination General appearance Neurological status- conscious, confused, comatose.Glassgow coma scalePupillary examinationNormal – Celphos poisoningMiosis – Opioids, OP poisoningMydriasis – TCA, Theophylline, Dhatura, MethanolConvulsions - Ethylene glycol, Lithium, SSRIMuscular fasciculations – OP poisoning
17 Hypotension with bradycardia :- Vital parameters –Cardiorespiratory system PR, BP, RR, TempHypotension with bradycardia :-Beta blockers, Cyanide, Benzodiazepines, Barbiturates, Opioids, Alchohol , OP insecticidesHypotension with tachycardia :-Beta -2 stimulants, Caffeine ,Theophylline, Amatoxin containing mushroom
19 Vital parameters contd…….. Body tempeartureHypothermia :-Barbiturates, Benzodiazepines, Ethanol, Opiates, Cyclic antidepressantsHyperthermia :-Amphetamines, Alcohol withdrawal, MAO inhibitors, Anticholinergic agents, Salicylates
20 Examination of Skin colour and lesions Colour Toxin/ poisonPink CyanideYellow ( jaundice) Phosphorus ,hepatotoxins (Acetaminophen, mushroom )Red RifampicinBlue (cyanosis) Aniline, Nitrites, MethemoglobinemiaDiaphoresis –Salicylate, OP poisoningSympathomimetics, serotonin syndromePhencyclidine, alcohol or sedative withdrawal
21 Examination of Skin colour and lesions contd…. c. BruisingDiffuse ecchymosis:-Anticoagulant poisoningRodenticidesd. Needle tracksI/V abuse :-OpiatesAmphetaminesCocaineMay be hidden in groin or interdigital spaces
22 Examination of Skin colour and lesions contd…. e. HairHair loss – Chemotheapuetic agentsThalliumf. NailsMee’s lines – Arsenic poisoning
27 Other Abnormalities Hyperkalemia Hypokalemia Hypernatremia Digoxin, Cardiac glycosides, Rhabdomyolysis, K + sparing diureticsHypokalemiaTheophylline, Amphetamines, SympathomimeticsHypernatremiaUncommon in clinical toxicologyLarge dose of NaHCO3 for TCA overdoseCorrection of life threatening metabolic acidosisHyponatremiaRare
31 ECG abnormalities Usually non specific ECG abnormality Drugs/ toxins 1. Bradycardia & AV BlockBarbiturates, ß- blockers, Antiarrhythmics2. Ventricular tachyarrhythmiasCardiac glycosides, Fluorides, Membrane active agents, Sympathomimetics3. QRS prolongationAmantidine , Hyperkalemia4. QT prolongationAmantadine, Amiodarone, Thallium
32 Radiological studies Bio assays of drugs Not particularly helpful in diagnosis.May be useful in confirming :-Ingestion of metallic objects.Packets of heroin / cocaine ( body packing)Serial chest X-ray - Aspiration pneumonitis, ARDSBio assays of drugsAcetaminophenAcetoneEthylene glycolMethanolSalicylatePhenobarbitalTheophyllineLithium
33 Toxicologic analysis Interpretation requires various methods:- Urine , blood, gastric contents – confirm or rule out suspected poisoning.Interpretation requires various methods:-Thin layer chromatography – AcetaminophenGas liquid chromatography – BZD, AmphetaminesHPLC- BZDMass spectrometry- AnticonvulsantEnzyme assaysRBC cholinestrase , serum cholinestrase – OP poisoningPseudocholinestrase levels – OP poisoning
34 Fundamentals of poisoning management Initial resuscitation and stabilizationRemoval of toxin from the bodyPrevention of further poison absorptionEnhancement of poison eliminationAdministration of antidoteSupportive treatmentPrevention of re - exposure
35 Management of poisoning contd…. Initial resuscitation and stabilization –I/V access – I/V fluidsEndo tracheal intubation - to prevent aspirationUnconscious patientsRespiratory depression/ failureConvulsions- give anticonvulsantsRemoval of toxin from the bodyCopious flushing with water or saline of the body including skin folds, hairInhalational exposureFresh air or oxygen inhalation
36 Prevention of poison absorption G I decontaminationPerformed selectively, not routinelyGastric lavageUseful IF DONE BEFORE 3 hr of ingestion of a poisonDone with water ( except infants – NS), 1:5000 potassium permangnate , 4% Tannic acid, saturated lime water or starch solutionAdministering & aspirating 5ml/kg through a No. 40 F orogastric tube ( No. 28 F – children) or Ewald’s tubePosition – Trendelenburge & left lateral positionPerformed until clear fluid is obtained or a maximum of 3 L
37 Prevention of poison absorption contd…. ComplicationsAspiration (common)Esophageal / gastric perforationTube misplacement in the tracheaEwald’s gastric tube
38 Prevention of poison absorption contd…. ContraindicationsCorrosive poisoning – GE perforationPetroleum distillate ingestants- Aspiration pneumoniaCompromised unprotected airwayEsophageal / gastric pathologyRecent esophageal / gastric surgeryLavage decreases ingestant absorption by an average of :-52 % - if performed within 5 mins of ingestion26 % - if performed at 30 mins16 % - if performed at 60 mins
39 Prevention of poison absorption contd…. 2. Ipecac Syrup induced emesisUsed for home management of patients with :-Accidental ingestionsReliable historyMild predicted toxicityAministered orallyDose :-30 ml – adults15 ml – children10 ml – small infants
40 Ipecac irritates the stomach & stimulates CTZ centre. MOAIpecac irritates the stomach & stimulates CTZ centre.Vomiting occurs about 20 min after administrationDose may be repeated if vomiting does not occurSide effectsProtracted vomitingContraindicationsGastric / esophageal tears or perforationCorrosivesCNS depression or seizuresRapidly acting CNS poisons ( cyanide, strychnine, camphor )
41 Prevention of poison absorption contd……. 3. Activated charcoalGreater efficacyLess invasiveGiven orally as a suspension ( in water ) or through NG tubeDose – 1 g/kg body wt.Charcoal adsorbs ingested poisons within gut lumen allowing charcoal- toxin complex to be evacuated with stool or removed by induced emesis / lavage
42 Prevention of poison absorption contd… Indications- Barbiturates, Atropine , Opiates, StrychnineContraindications - Mineral acids, alkalis, cyanide, fluoride ,ironSide effectsNausea , vomiting, diarrhoea or constipationMay prevent absorption of orally administered therapeutic agentsComplicationsAspiration – vomitingBowel obstruction
43 Prevention of poison absorption contd…. 4. Whole bowel irrigationAdministration of bowel cleansing solution containing electrolytes & polyethylene glycolOrally or through gastric tubeRate – 2 L/ hr ( 0.5 L /hr in children)End point- rectal fluid is clearPosition – sittingIndication :-Slow or enteric coated medicationsPackets of illicit drugsHeavy metalsIron , Lithium
46 Enhancement of elimination of poison 1.Alkalization of urineUrine pH ≥ 7.5Urine output 3-6 ml/kg5% Dextrose in 0.45 NS containing 20 – 35 meq /L Of NaHCO3 to an IV solutionUses – Chlorpropamide, Phenobarbital, Sulfonamides, SalicylatesC/I :-Congestive heart failureRenal failureCerebral edema
47 2. Acidification of urine Enhance elimination of weak bases such as Phencyclidine & AmphetamineNot used anymoreS /E- Metabolic acidosis, Renal damage3.Extra corporeal removalDialysisAcetone, Barbiturates, Bromide, Ethanol, Ethylene glycol, Salicylates, LithiumLess effective when toxin has large volume of distribution (>1 L/kg), has large molecular weight, or highly protein bound
48 Elimination of poison contd…. Peritoneal dialysisAlcohols , long acting salicylates, LithiumExchange transfusionIndicationsFatal , irreversible toxicityDeteriorating despite aggressive supportive therapyDangerous blood levels of toxinsLiver or renal failureEg. Arsine or Sodium Chlorate poisoning
49 Elimination of poison contd…. 4. ChelationHeavy metal poisoningComplex of agent & metal is water soluble & excreted by kidneysEg . BAL, EDTA, Desferrioxamine, DMSABAL – Arsenic, Lead, Copper, MercuryEDTA- Cobalt, Iron, CadmiumDesferrioxamine – IronDMSA- Lead, Mercury
50 Administration of Antidotes Not all poisons have antidotes.PoisonAntidoteDoseAcetaaminophenN - acetylcysteine140mg/kg. then 70 mg/kg every 4 hrs to total of 18 doses over 72 hrsBenzodiazepineFlumazenil0.1mg/min infusion to a total of 1mgAnticholinergicsPhysostigmine1gm I/M or I/VOpioidNaloxone2 mg I/V , repeated every half to one min to a total of 20 mg I/VCyanideThiosulphate , nitrite0.3 g sodium nitrite in 10 ml sterile water iv. 25 g sodium thiosulphate iv slowIronDesferrioxamine2g im 12 hrly or mg/kg/hr not to exceed 80 mg /kg /24 hrs
51 Administration of antidotes…. PoisonAntidoteDoseOP PoisoningAtropine , OximesAtropine : Loading dose - 2 , 4 , 6 every 5 mins .Maintenance – infusion < 3mg/hrPAM – mg/kg IV to be repeated 6-12 hourlyInfusion – mg/kg f/b 5-10mg /kg/hMethanolEthanol , FomepizoleEthanol 50% 1 ml/kg every 2 hr for 5 daysFomepizole 15 mg/kg loading dose f/b 10 mg/k every 12 h for 4 days
52 Supportive careHemodynamic support- Hypotension unresponsive to volume expansion – t/t with ionotropesCorrection of temperature abnormalitiesHypothermia – Rewarming of the patientActive / passive methodsExternal / internal methodsPassive external rewarming- blankets / sleeping bagsActive external warming- hot water bottles, heating blankets , forced air warmingInvasive core rewarming- peritoneal dialysis, hemodialysis, gastric or rectal lavage
53 Supportive care contd…. HyperthermiaExternally – immersion in iced saline bath, tepid spongingInternally – gastric / peritoneal lavageCorrection of metabolic derangementsHyperkalemia –Calcium gluconate 10% mlInsulin 10 units with 50g of 50% dextroseNaHCO3 1mmol/kg , beta-2 agonistsHypokalemia -K < 2.5 mmol/l with symptoms - I/v KCL mmol/hK < 3.5 but > 2.5 mmol/l with no symptoms – KCL mmol every 4-6 hr
54 Supportive care contd…. Hypernatremia with hemodynamic instability-NS saline till I/V vol is corrected.Subsequently replace water with 5% D, or 0.45% NSPrevention and t/t of secondary complications – pulmonary edema , cerebral edema, shock etc.Pulmonary edema – Furosemide IV mg/kgMorphine IV 2-4 mgNitroglycerin SLO2 inhalation / intubation as neededCerebral edema – Mannitol 1g/kgSteroids – Hydrocortisone, DexamethasoneShock – crystalloids / colloids
55 Prevention of re- exposure Adult education – instructions regarding safe use of medications & chemicalsNotification of regulatory agencies - in case of environmental or workplace exposurePsychiatric referral- depressed or psychotic patients should receive psychiatric assessment, disposition & follow-up
56 Prevention of re- exposure Child proofing- In house hold where children live or visit, alcohols, medications, household products ,non edible plants should be kept out of reach or in locked, child proof containers.
57 Summary Poisoning a common problem in our country A high index of suspicion required to diagnoseFor any poisoning the mainstay of treatment is supportive careFollow the A, B, CDon’t panic and follow a plan of actionDecreasing absorptionEnhancing eliminationNeutralising toxins
58 REFERENCESCritical care toxicology: Diagnosis and Management of the Critically Poisoned Patient. Jeffery Brent ;2nd edition.Harrison’s Principles of Internal Medicine. 16th edition, Vol 2: part 16; Poisoning, Drug overdose, and Envenomation.The Essentials of Forensic Medicine and Toxicology. Dr. K. Reddy , Section II Toxicology; 25th editionInternational Programme On Chemical Safety, Guidelines On The Prevention Of Toxic Exposure ; WHO 2004– Official data , D. Gunnell, 2007Critical Care, Joseph M. Civetta ; 4th edition