Certificate Program In Clinical Toxicology 2021 PDF

Certificate Program in Clinical Toxicology 2021 Treatments in Clinical Toxicology Dr. YC Chan Hong Kong Poison Information Centre 17 April 2021 Hong K...

Certificate Program in Clinical Toxicology 2021 Treatments in Clinical Toxicology Dr. YC Chan Hong Kong Poison Information Centre 17 April 2021 Hong Kong Poison Information Centre  Treatments in Clinical Toxicology Concept & Basics Supportive & Empirical treatment GI decontamination Antidotes Enhanced Elimination Investigational Therapy Hong Kong Poison Information Centre  Treatment – Benefit Vs Risk To give Risk Benefit Major None / Minimal Moderate Mild Small Moderate None/Minimal Major Not to give Hong Kong Poison Information Centre  Pyramid of Poisoning Benefit / Risk Ratio Low High Treatments Severity Hong Kong Poison Information Centre  Poisoning - Management Specific Treatment Antidote Decontamination (Acute Poisoning) Exposure Termination (Chronic Poisoning) Supportive Management Hong Kong Poison Information Centre  Poisoning in Hong Kong Hong Kong Poison Information Centre  Supportive Measure Stabilization of the ABC Good nursing care Monitoring of vital signs, expected toxicity and its progress Use of oxygen, dextrose, intravenous fluid and other treatment as indicated Specific Treatment Prevention of secondary injury Antidote Decontamination Exposure Termination Supportive Management Hong Kong Poison Information Centre  Decontamination Get rid of the poison before absorption GI decontamination Specific Treatment Surface Antidote Water +/- soap NS/Water for eye irrigation Decontamination Supportive Management Hong Kong Poison Information Centre  Method of GI decontamination Single Dose Activated Charcoal (AC) +/- Cathartics (Only used with the 1st dose of AC) Multiple Dose Activated Charcoal (MDAC) Whole Bowel Irrigation (WBI) Gastric Lavage (GL) Surgical Intervention Ipecac Induced Vomiting (Not considered in hospital setting) Hong Kong Poison Information Centre  Activated Charcoal Activation → increased surface area Hong Kong Poison Information Centre  Activated Charcoal – Single Dose Indications Potential toxic amount ingestion Within 1-2 hours 1g/kg or 50gm in adult Contraindications Poison not absorbed by AC Intestinal Obstruction Caustic Ingestion NO forced AC (e.g. R/T in unprotected airway) Hong Kong Poison Information Centre  MDAC GI decontamination Single dose may not be adequate Enhanced Elimination Enterohepatic re-circulation Gut dialysis Hong Kong Poison Information Centre  Enterohepatic & Enteroenteric Removal Hong Kong Poison Information Centre  When to consider MDAC Recommended by Possible Beneficial Position Statement Aspirin, Aminophylline Aminophylline Barbiturates Barbiturates Carbamazepine Carbamazepine Dapsone, Digoxin, Dilantin Dapsone Extended release, Epilim Quinine Quinine ABCDQ ABCDEQ Hong Kong Poison Information Centre  MDAC Administration MDAC dose 1g/kg as initial dose Then 0.5g/kg Q2-4H X 4 doses Sorbitol usually given with the 1st dose of charcoal Maximum 1 dose / day Ensure functioning bowel & airway protect Hong Kong Poison Information Centre  AC – Complications Aspiration pneumonitis Intestinal obstruction (MDAC) Acute appendicitis Constipation Hong Kong Poison Information Centre  Activated Charcoal in 2021 High level of evidence still scanty Should not be a “routine” anymore Compose the majority of GI decontamination, but its use is decreasing Aim to identify indicated patient for its use Hong Kong Poison Information Centre Hong Kong Poison Information Centre  Pre-Hospital Activated Charcoal Hong Kong Poison Information Centre Hong Kong Poison Information Centre  Gastric Lavage Only removes toxins that fit through holes In human volunteers and poisoned animals ~ 30% recovery Wide variation Hong Kong Poison Information Centre  Gastric Lavage - Risk Aspiration Esophageal/Gastric trauma Airway trauma Increased vagal tone Hypoxia Risk reduced but not abolished by intubation Hong Kong Poison Information Centre Hong Kong Poison Information Centre  Overall Data for GL Not necessary in mild/moderate poisoning In severe poisoning Inadequate no. of the sickest patients studied, who would most likely benefit from gastric emptying Just because a benefit wasn’t shown after one hour, doesn’t mean that doesn’t exist ! 1. Kulig K, Bar-Or D, Cantril SV, et al: Management of acutely poisoned patients without gastric emptying. Ann Emerg Med 14:562-567, 1985 2. Merigian KS et al. Prospective Evaluation of Gastric Emptying in the Self-Poisoned Patient. Am J Emerg Med 1990;8:479-483 3. Pond SM, Lewis-Driver DJ, Williams GM, et al: Gastric emptying in acute overdose: A prospective randomized controlled trial. Med J Aust 163:345-349, 1995 Hong Kong Poison Information Centre  My bottom line GL did help certain poisoned patients Not clearly defined by “evidence” Most case will do alright without GL Benefit Vs Risk consideration in each case Lower threshold in Intubated cases Ineffective alternative treatment Really sick and “dying” Hong Kong Poison Information Centre  GL Conclusion – 2013 Statement The conclusion remains the same as in 2004 GL should not be performed routinely, if at all, for the treatment of poisoned patients In the rare situation where gastric lavage might seem appropriate, clinicians should consider treatment with activated charcoal or observation and supportive care in place of gastric lavage New evidence since 2004 suggests the need to emphasize that GL should be performed only where the expertise exists Hong Kong Poison Information Centre  Whole Bowel Irrigation WBI with PEG decreases GI transit time Wash the toxin out Hong Kong Poison Information Centre  2014 Position Statement WBI can be considered for potentially toxic ingestions of sustained-release or enteric-coated drugs, particularly for those patients presenting later than 2 h after drug ingestion when activated charcoal is less effective WBI can be considered for patients who have ingested substantial amounts of iron, lithium, or potassium as the morbidity is high and there is a lack of other potentially effective options for gastrointestinal decontamination WBI can be considered for removal of ingested packets of illicit drugs in “ body packers ” Hong Kong Poison Information Centre  WBI Dose 1-2 L/hr in adults, until effluent in clear 300-500 cc/hr in children +/- IV Maxalon + Erythromycin Contraindications Bowel obstruction or ileus Haemodynamically instability Hong Kong Poison Information Centre  Surgical Removal Hong Kong Poison Information Centre  Ipecac It makes you vomit No longer recommended by the AAP Consensus documents and position papers offer little support for ipecac Should not consider in hospital setting Hong Kong Poison Information Centre  Acute Poisoned Patient 2 Main Questions Need of GI decontamination Yes or No Choice of decontamination methods Hong Kong Poison Information Centre  More Questions – Poison Factors Expected toxicity Expected amount of poison amendable to GI decontamination Activated charcoal affinity An antidotes or treatment? Caustic injury? Hong Kong Poison Information Centre  More Questions – Patient Factors Significant spontaneous vomiting Current status Vitals Mental Current GI tract function Co-morbidity Hong Kong Poison Information Centre Hong Kong Poison Information Centre  GI decontamination - Summary GL in life threatening poisoning presented “early” AC is generally safe and simple, enough in majority of the indicated cases, but NOT a routine Decreasing use in US, ? In HK MDAC/ WBI/ Surgery rarely Induced vomiting – Forget it ! Always consider the risk/benefit ratio before performing a decontamination procedure Hong Kong Poison Information Centre  Antidotes To counteract the effect of the poison Multiple mechanisms PK & PD Specific Treatment Antidote Decontamination Supportive Management Hong Kong Poison Information Centre  HA Antidotes 3 levels Level I – Acute Hospital Level II – Cluster Level III – Central Depends Clinical Efficacy Expected Case Numbers Cost Effectiveness Hong Kong Poison Information Centre  Level I Hong Kong Poison Information Centre  Level II & III Hong Kong Poison Information Centre Hong Kong Poison Information Centre  Antidotes - Naloxone A competitive opioid receptor (µ) antagonist Indications Opioids Poisoning Other Clonidine Valproate Acid ACE I Etc ……. Hong Kong Poison Information Centre  Naloxone Dose Initial dose (0.1mg – 2 mg) Repeat or double if no response Duration of action ~ 1-2 hrs Shorter than most Opioids Consider non-response (not opioids poisoned) 2mg for typical opioids (morphine/heroin) Up to 10mg for atypical opioids (propoxyphene) Hong Kong Poison Information Centre  Antidotes - Benzodiazepine Poison induced seizure Poison induced agitation Alcohol / Sedative withdrawal Chemical Cooling Heat is a rapid killer ! Cocaine – ACS / HT emergencies Hong Kong Poison Information Centre  Antidotes - NaHCO3 Na effect Alkalization effect Urinary Serum Neb NaHCO3 Hong Kong Poison Information Centre  NaHCO3 - Indications Na effect + Serum alkalinization TCA Poisoning / Na blocking agents Serum + Urinary alkalinization Salicylates Poisoning Cl2 gas inhalation Urinary alkalinization (Enhanced Elimination) Hong Kong Poison Information Centre  Antidotes - Flumazenil A competitive benzodiazepine receptor antagonist Indications Selected cases of benzodiazepine poisoning Maybe a valuable tool in management of selected patients with coma of unknown etiology Most US literature - Risk > Benefit Most European literature - Benefit > Risk Hong Kong Poison Information Centre  Flumazenil NOT as routine use in “coma cocktail” anymore Contraindications Chronic Benzodiazepine Use TCA poisoning Prior seizure history Ingestion of pro-seizure & pro-arrhythmic agents From GTE 8th Dose → 0.2mg + 0.3mg + 0.5mg (every 30s) Hong Kong Poison Information Centre  Specific Treatment Enhanced Elimination (EE) Urinary Alkalization Direct Out Hemodialysis (HD), Hemoperfusion (HP) Hemofiltration (HF), Phasmapheresis Albumin dialysis, Exchange transfusion (ET) Specific Treatment CSF drainage and replacement Antidote ECLS Decontamination Liver Transplant Supportive Management Hong Kong Poison Information Centre  Consider EE in Life-threatening clinical toxicity Amount taken / Level indicate severe morbidity or mortality is likely Impair normal route of elimination Fail to respond to full supportive measures Hong Kong Poison Information Centre  Urinary Alkalization Salicylate Phenobarbital When MDAC is contraindicated Methanol/ Formate Chlorpropamide MTX 2-4D Hong Kong Poison Information Centre  Dialyzable Poison HD Size < 500 dalton Vd < 1L/kg Low protein bound Charcoal HF Vd < 1L/kg Binds to Charcoal Hong Kong Poison Information Centre  HD List M - Methanol, Metformin E - Ethylene Glycol T - Theophylline A - Aspirin L - Lithium Etc…………….. Hong Kong Poison Information Centre  HF Potential List Theophylline Thallium EG Mercuric salts Methanol Tetramine Lithium Chloroquine, Quinine Aminoglycosides Flecainide Metformin induced lactic Methotrexate acidosis Paraquat, Diquat TCA Hong Kong Poison Information Centre  Determinants Xenobiotic properties (Toxin) Clinical condition (Patient) Practical & Logistic issue (Facility) Hong Kong Poison Information Centre  Courtesy to Hong Kong Poison Information Centre  Courtesy to Hong Kong Poison Information Centre  Courtesy to Hong Kong Poison Information Centre  EXTRIP Workgroup EXtracorporeal TReatments In Poisoning Hong Kong Poison Information Centre  Recommendation APAP Barbiturate Carbamazepine Digoxin Lithium Metformin Methanol Salicylate Theophylline Thallium Lithium Valproate Hong Kong Poison Information Centre  APAP Hong Kong Poison Information Centre  Lithium Hong Kong Poison Information Centre  Forget it ! Acetazolamide to alkalinize urine Worsens tissue pH Acidification of urine for phencyclidine May worsen outcome Peritoneal dialysis Forced Diuresis + Diuretics Hong Kong Poison Information Centre  THANK YOU Hong Kong Poison Information Centre