ACUTE POISONING - MANAGEMENT

1. ACUTE POISONING -MANAGEMENT Ayman M. Kamaly, MD Professor of Anesthesiology Ain Shams University kamaly3@hotmail.com

2. INTRODUCTION • Acute poisoning is a common medical emergency in any country. • The exact incidence of this problem in our country remains uncertain.

3. For effective management of an acutely poisoned victim, 5 steps are required: • Resuscitation and initial stabilization • Diagnosis of type of poison • Nonspecific therapy • Specific therapy • Supportive care

4. Resuscitation and Initial Stabilization Initial management: ABCDs • Airway • Breathing • Circulation

5. Lessons from History... • A young princess ate part of an apple given to her by a wicked witch

6. She was found comatose and unresponsive, as if in a deep sleep, • Airway positioning and mouth to mouth ventilation were performed, • and she was fully recovered.

7. Lessons: • Best Antidote = Good Supportive Care (Love’s first kiss) • Airway issues is a still the major cause of morbidity in toxicology as in other aspects of emergency.

8. Circulation = Plumbing • Pump working? • Inotrope • Enough volume (is it primed)? • Hypovolemia? • IV fluid challenge • Adequate resistance (no leaks)? • Inadequate vascular resistance? • Norepinephrine, phenylephrine

9. Initial management: ABCDs Treat problems as you find them!! • Airway, • Breathing, • Circulation, • Drugs, • Decontamination, • Detoxication, • Disability – GCS/AVPU and Pupils, • DON’T EVER FORGET GLUCOSE.

10. Don’t forget GLUCOSE “A stroke is never a stroke until it’s had 50 of D50” • Empiric administration of dextrose??! • Check the blood sugar using a reliable bedside test • Administer dextrose ONLY if the RBS is <80 mg/dl.

11. Diagnosis of Type of Toxin • What? • When? • How much? (mg/kg) • What else? • Why? A) History Be a Detective

12. Collateral history • Paramedics • Family / friends • Notes • Look in pockets – carefully!!! Look for Clues

14. B) Examination

16. Investigations • All Patients • Glucose • Paracetamol & Salicylate • As indicated • LFT • RFT, Lytes • Co-ag / INR • CK • ABG / VBG • Urine toxicology screen

17. Investigations • Urine toxicology screen • Pinkish urine --->>> phenothiazine, • Chocolate colored --->>> met-hemoglobinaemia, • Oxalate crystals --->>> ethylene glycol, • Ketonuria (without metab. changes) --->>> Salicylate

18. Investigations • Abdominal X-Ray (Radiopaque Toxins) • Chloral hydrate, iodides, • Heavy metals, iron, • Sustained release pills, • Solvents (Chloroform, CCL4)

19. Non-Specific Therapy • Aim: • Reduce absorption of poison from the gut, • Increase excretion of absorbed poison.

20. A.Reducing absorption 1) Emesis • Syrup of Ipecac • Amount of recovered toxin is highly variable • Effective within ONEhour • Contraindicated: • Comatose/Convulsing • Ingested corrosive or hydrocarbon*

21. 2) Gastric Lavage • Lt Lat Position + head down • to prevent aspiration & ↓ pushing lavage into duodenum. • If unconscious  ETT • Effective within 1-2hours • Contraindicated: • Strong corrosive or • Volatile hydrocarbons

22. 3) Activated Charcoal • Small particle size & enormous surface area, • Bind most drugs & toxins, • Dose: 1 g/kg • Exceptions: • Iron, Lithium, Metals, • Methanol, Ethanol, Hydrocarbons, • DDT

23. Activated Charcoal (cont.) • More effective than Ipecac, Gastric Lavage • First choice for most Over Doses

24. 4) Whole Bowel Irrigation • Isotonic soln. of Polyethylene glycol (2 L/hr) • Not absorbed from intestine (mechanical flush) • Good for: • Iron, Lithium, • Sustained-release pills, • Foreign bodies, • Drug “packets”

25. B.Increasing Excretion • Forced AlkalineDiuresis • Principle:Renal tubular epith is impermeable to ionized (+) molecules. If the urinary pH is changed so as to produce more of ionized form, it is trapped in the tubular fluid & is excreted in the urine. • Useful in: • Salicylates, • Phenobarbital, • Lithium

26. Forced AlkalineDiuresis (Cont.) • Method: • D5% - ½ NS + bicarbonate 20-35 mEq/L to produce a urine output of 3-6 ml/kg/hr & a urine pH 7.5-8.5. • Diuretics are often needed to maintain high urine flows. • KCl is added to prevent ↓K+, • Contraindications: • Shock, • Hypotension, CHF, • Renal failure

27. 2) Multiple-Doses Activated Charcoal • 1 g/kg/1-4 hrs • To maintain intestinal toxin conc. near-zero (Gastrointestinal Dialysis). • Indicated in toxins with : • Long ½ life, • Enterohepatic circulation ( Digoxin, Phenobarbitals, Theophylline), • Sustained-release preparations, • Massive toxin dose to be effectively adsorbed by single charcoal dose

28. 3) Dialysis (Peritoneal/Hemo) • For H2O soluble & Low MW compounds. • Useful in: • Ethanol, Methanol, • Salicylates, • Theophylline, • Ethylene glycol, • Phenobarbital • Lithium

29. Specific Therapy

30. Supportive Therapy • Try to maintain functions of CNS, CVS, Renal, … • Care for coma, seizures, hypotension, arrhythmias, hypoxia, …

31. Exposure to toxins could be through routes other than ingestion (Cutaneous, Ocular) • Antidotes are NOT available for every toxin

32. However; when Antidote is Present the effect is Dramatic

33. Legal Aspects • The 1st sample of gastric lavage should be collected in “clean” container (Contamination !!). • Container should be sealed using a glue paper before sending for toxicological screening.

34. After sealing Blood & Urine collection tubes and bottles, pt’s information should be written on the labels & affixed @ the juncture between the cap & the bottle. • POLICE should be informed !!

35. Clinical Scenarios

36. Paracetamol • Very common: 40% poisons admissions • Often asymptomatic • Can be lethal – 200-300 deaths/year • Check blood level at 4 hours • Two treatment lines normal and high risk

37. Prescott Nomogram

38. Paracetamol metabolism • Metabolised by: • Glucuronidation (60%), • Sulphation (35%) • Oxidation (10%) by Cytochrome p450 produces NAPQI (toxic  hepatocellular necrosis) • NAPQI detoxified by conjugation with glutathione.

39. High Risk pt. • Increased oxidation pathway (enzyme induction) • Chronic alcohol use • Drugs • Reduces glutathione stores • Malnutrition • Eating disorders • Chronic liver disease

40. N-Acetylcysteine • Most effective within 8hours • Precursor for glutathione production • Can cause anaphylactoid reactions !! • Consider starting before paracetamol result if: • Presenting > 8 hrs & > 150mg/kg taken • Other accompanying overdose.

41. Patient 1 • 20 year old woman who takes a handful of paracetamol tablets • No drug history • No alcohol use • Fit and well • Blood level is 80mg/L after 4 hrs.

42. No need to treat • Patient is not high risk • Level at 4 hours is below even the high risk line

43. Patient 2 • 70 year old man • Takes 20 paracetamol 6 hours before presenting • Alcoholic • No drug history • Blood level 100mg/L

44. Treat • High risk patient • Level above the high risk line

45. Patient 3 • 17 year old epileptic • 25 tab Panadol 2 hours before attendance • Taking carbamazepine • Blood level at 4 hours is 120mg/L

46. Treat • High risk patient • Level above the high risk line

47. Patient 4 • 35 year old man who presents after taking 24 paracetamol over a period of 24 hours • No drug history • Fit and well • Blood level 20mg/L

48. Treat • Staggered overdoses are difficult • Level is above the treat-line in context to time • Need to monitor Liver function, clotting and renal function • May need discussing with Liver Unit if abnormal

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50. Some Famous Historic Poisonings