Toxicology: The Clinical Side

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Toxicology The Clinical Side

• Dr. Sunil Sookram, MD, FRCPC
• Assistant Clinical Professor
• Division of Emergency Medicine
• University of Alberta

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Objectives

• To overview a systematic emergency medicine
  approach to the resuscitation, diagnosis, work-up
  and treatment of the acutely poisoned patient.
• To discuss the specifics of toxicological
  resuscitation.
• Discuss common overdoses ASA, Tylenol.

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Objectives

• To discuss the risks and benefits of
  decontamination
• To discuss the five most common toxidromes and
  their antidotes.
• To discuss the utility of the EKG, ABG, osmolar
  gap and APAP in the tox patient.

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Case Presentation

• A 16 y.o. male presents to the ED with 2 EMS
  workers and 6 police. He was found punching cars
  on the freeway. He is in 6-point restraints
  yelling wildly in the ambulance bay.
• VS HR 161, BP 160/95, RR 30, T 37.5oC
• OE agitated pupils 6mm, reactive
• skin wet, hot BS increased

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Overdoses and Poisonings

• Very common presentation to ED
• Intentional overdoses vs. Accidental poisonings
  vs. Industrial/Terrorism
• Care is coordinated effort by EMS, Emergency
  Medicine, Internal Medicine/Critical Care
• In intentional overdose need input from
  Psychiatrists
• Resources Databases and Poison Centre

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Case Presentation (cont)

• What is your diagnosis?
• What do you do first?
• Where would you put him?
• What would you give to sedate?
• What would you give if he developed
• Convulsions?
• V Tach?
• What tests would you do?

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Resuscitation of the Poisoned Patient

• Always start with the ABCs.
• A - Loss of airway is the most lethal
  toxicological complication.
• B - Many drugs depress respiration
• C - Many drugs cause cardiovascular collapse
• D - Decontamination to prevent further absorption
• E - Elimination of toxic agents from body
• F - Find and administer the antidote (if one
  exists)

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Approach to the Poisoned Patient

• ABCs
• Decontamination
• - Lavage, Charcoal, WBI, saline flush
• Increase Excretion
• Dialysis, diuresis, ion trapping, MDAC,
  hemoperfusion
• Specific Antidotes

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Resuscitation of the Poisoned Patient

• For patients with a decreased LOC consider the
  Coma Cocktail
• Dextrose after checking Chemstrip if BG low
• Oxygen
• Naloxone (Narcan) 0.4 - 0.8 mg (0.01 mg.kg) SQ/IV
• Thiamine 100 mg IV/IM/po
• BZPs (vs. dilantin) for seizures.
• Dont forget maximal supportive therapy!

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Decontamination

• Gut Decontamination
• Expulsion from GI tract
• Emesis (ipecac)
• Lavage
• Decrease absorption
• Charcoal
• Whole Bowel Irrigation

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Gastric Lavage

• Big tube into stomach

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Activated Charcoal

• Adsorbing agent
• Want to try some ????

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Decontamination

• Skin
• saline flush aggressively
• Eyes
• need to flush eyes

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Decontamination of Concretions

• B arbituates
• I ron
• G lutethimide
• M eprobamate
• E xtended release theophylline
• SS alicylates

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Elimination

• Saline diuresis
• Charcoal hemoperfusion
• Hemodialysis

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Elimination

• Dialysis an option with
• S alicylates
• T heophyline
• U remia
• M ethanol
• B arbituates
• L ithium
• E thylene Glycol

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Drugs that Cause Seizures

• W - withdrawl of alcohol or benzodiazepines
• I - INH
• T - theophylline
• H - heavy metals
• L - lithium
• A - antibiotics (Eryth), anticonvulsants
• C - camphor, cocaine, CCB
• O - organophosphates
• P - pesticides, phenothiazines
• S - sympathomimetics, salicylates

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The Poisoned Patient

• Often not reliable historian, or young child
  unwilling/unable to give history
• Can have ETOH on board
• assess mental status and capability to make
  decisions - FORM 1 to ensure compliance and
  allows you to hold patient against wishes
• Needs constant reassessment as condition does
  change

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The Tox Screen

• Every poisoned patient should have an EKG, ABG,
  ASA, and acetaminophen level.
• Can calculate Anion Gap and Osmolar Gap from
  Electrolytes.
• Further testing should be based on the above
  results and the patients toxidrome.
• Qualitative testing does not add to patient care.

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The Laboratory Tests

• Labs help confirm the diagnosis
• Labs help to determine the extent of intoxication
• Use history, clinical examination and labs to
  manage the patient

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Anion Gap

• AG (sodium) - (bicarbonate chloride)12-16
• High Anion Gap Metabolic Acidosis
• Methanol
• Uremia
• Diabetic Ketoacidosis
• Paraldehyde
• INH, iron
• Lactate
• Ethylene glycol
• Salicylates
• Cyanide
• Alcoholic Ketoacidosis
• Toluene

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Osmolar Gap

• Calculated Osmoles
• 2(sodium) urea glucose 290-300
• osmolar gap
• calculated - measured osmoles 0-10
• Theoretically, unaccounted osmols may signify a
  toxic alcohol ingestion.(i.e.. ETOH)
• Not sensitive enough to rule out a toxic alcohol
  ingestion.

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Increased Osmolar Gap

• M annitol
• A lcohols
• D ye, DMSO
• G lycerol
• A cetone
• S orbital

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The ABG

• A normal pH and anion gap rules out many
  ingestions
• e.g. ASA, cyanide, toxic alcohol
• If a patient ingested ETOH and a toxic alcohol,
  he may not become acidotic until his ETOH is
  cleared.
• Consider serial ABGs or toxic alcohol levels

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TCA effect on the EKG

• Absence of a terminal R wave excludes TCA use.
• Look for a positive deflection
• in the terminal 40 msec of aVR.

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ASA toxicity

• Uncouples oxidative phosphorylation
• respiratory alkalosis and metabolic acidosis
• chronic and acute overdoses
• can have normal ASA levels and still be toxic
• treatment is based upon clinical condition and
  level of toxicity

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Acetominophen level

• APAP OD is asymptomatic until too late.
• Everyone gets an APAP level.
• Compare level on Nomogram.
• Antidote available if in toxic levels
• (NAC) N-Acetylcysteine
• can be used up to 72 hours from time of ingestion
• Preferably initiated before 8 h from ingestion

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Clinical Toxidromes

• A constellation of clinical signs and symptoms
  that will help identify the specific toxin
  ingested.
• Need high index of suspicion, history and good
  physical exam

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Some common Toxidromes

• Constellation of signs and symptoms
  representative of a toxin

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Anticholinergics(anti-histamines, TCAs,
atropine)
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Cholinergics(nerve gas, pesticides)
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Opiods(heroin, codeine)
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Sedative Hypnotics(alcohol, benzodiazepines)
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Sympathomimetics(cocaine, metamphetamine)
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Case

• A community hospital calls with the pediatrician
  requesting to talk to the Emergentologist. He
  has 3 cases of children who smoked Jimson Weed
  and are acting strangely. He has had to
  physicially restrain them and does not know what
  to do.
• What do you tell him ?
• What is going on ?

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Case

• A child ingests a pesticide that was kept in the
  garage. He is brought to the ED by parents. You
  wisely call the Poison Centre and they tell you
  that the liquid contains a carbamate.
• What is this ?
• How does it change your management ?

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Case

• 16 year old street kid is brought to the ED by
  EMS. The child was shooting up heroin and
  collapsed 10 minutes later. You manage the ABC
• What signs and symptoms would you expect ?
• What toxidrome ?

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Case Presentation

• A 21 y.o. male presents to the ED with 2 EMS
  workers and 6 police. He was found punching cars
  on the freeway. He is in 6-point restraints
  yelling wildly in the ambulance bay.
• VS HR 161, BP 160/95, RR 30, T 37.5oC
• OE agitated pupils 6mm, reactive
• skin wet, hot BS increased

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Case Presentation (cont)

• What is your diagnosis?
• What do you do first?
• Where would you put him?
• What would you give to sedate?
• What would you give if he developed
• Convulsions?
• V Tach?
• What tests would you do?

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Tokyo Subway

• Terrorists release sarin gas into busy Tokyo
  subway. The severely poisioned patients suffer
  from excessive salivation, tearing, and
  respiratory failure. A few collapse and have
  generalized tonic clonic seizures.
• What toxidrome do you think they experienced ?

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Summary

• Always start with the ABCs.
• Decontaminate, decrease absorption, increase
  excretion, antidotes, supportive therapy.
• Use toxidromes and focused tox screen to guide
  therapy.
• Supportive therapy is vital.

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Questions ????

• Any at all...