Introduction to the Poisoned Patient

1
Introduction to the Poisoned Patient

• Department of Emergency Medicine
• The Ottawa Hospital

2
Outline

• Directed toxicology history
• Toxidromes
• Cases/Treatment

3
Toxicology - Objectives

• Determine whether poisoning has occurred, the
  substance involved, how severe the exposure was,
  how toxic it is likely to become, and the
  causticity of substance.
• Perform supportive care, decontamination or
  prevention of further absorption, give antidote
  where indicated, and enhance elimination of the
  poison.
• - Discuss special considerations in the
  management of poisoning with aspirin,
  acetaminophen, tricyclic antidepressants, and
  methanol.

4
Clinical Timeline
History
Toxidrome
Treatment
Laboratory
Confirm or refute
Reassess
5
Directed Tox History

• When (most NB)
• What
• How
• How much?
• Method?
• Whose?
• Compliance

• Coingestants?
• Access
• Specifics
• Self treatment?
• Ipecac
• Induced emesis
• Ethanol
• Intent?
• Symptoms

Work hard to get it, then be suspect!
6
Toxidrome

• What it is
• a clustering of symptoms and/or signs
• consistent with a class of drugs/medications
• What it isnt
• a way to identify a specific substance
• a way to discriminate well among contradictory
  agents until repeated over time

7
Common Toxidromes

• Narcotic (coma resp depression, miosis)
• Anticholinergic (mad as a hatter )
• Cholinergic (DUMBELS)
• Sedative/Hypnotic (pupillary rxn spared)
• Stimulant or Sympathomimetic
• Hallucinogens
• Extrapyrimidal
• Serotonergic

8
Anticholinergics

• TCAs, atropine, scopolamine, antihistamines
• Mad as a hatter (delerium)
• Hot as a hare (fever)
• Blind as a bat (mydriasis)
• Dry as bone (dry mucous membrane, urinary
  retention, decreased BS)
• Red as beet (flushing)
• Bowel and bladder lose tone and heart goes on
  alone)
• Difference with adrenergics
• Bowel sounds present
• Diaphoresis

9
Cholinergics

• Pheostigmine, organophosphtes (insecticides), and
  nerve gas (DUMBELS)
• Diaphoresis, diarrhea, decreased BP
• Urination frequent
• Miosis
• Bronchospasm, bronchorrhea, bradycardia
• Emesis, excitation of skeletal muscle
• Lacrimation
• Salivation / seizures

10
Sympathomimetics

• Amphetamine, cocaine
• Resemble paranoid schizophrenic
• CNS stimulation
• Seizures
• Psychosis
• Increased BP, pulse, Temp

11
Hallucinogens

• Hallucinations
• May be oriented to time / place / person
• Tachy
• HTN
• mydriasis

12
Opioids

• Coma
• Resp depression
• Miosis (not with demerol)

13
Sedatives

• Barbituarates, ethanol, benzos, ethanol, GHM
  (gamma hydroxybutyric acid)
• CNS depression
• Resp depression
• Coma
• Pupil rxn usually spared

14
Extrapyramidal

• chlorpromazine, stemetil, halodol,
  metocloperamide
• Dystonia (occulogyric crisis, laryngospasm,
  torticollis)
• Akithesia
• Parkinson like sx (tremor, ridgidity, akinesia,
  postural instability)
• Dyskinesia (tic, spasm, chorea, myoclonus)

15
Seratonergic

• Mimics NMS (neuroleptic malignant syndrome) of
  increased BP, increased pulse, increased temp,
  increased resp rate (onset within 24 hours,
  hyperactive, clonus, hyperreflexic, clonus)
• NMS (due to massive dopamine blockade) (FARMERS)
• Fever
• Autonomic changes (increased bp, pulse, sweating)
  / acidosis (rare)
• Rigidity of muscles / rhabdomyolyis
• Mental status changes (eg. Confusion)
• Elevated BP, HR, pulse, RR
• Rhabdomysolysis
• Seizures
• Onset days to weeks

16
Case
A 78 yo F presents with agitation and confusion.
BP 180/105, P 110 RR 16 T 38.2 C. Physical exam
reveals an acutely agitated pt, pupils 6 mm,
CVS/resp normal except tachycardia.
Is a toxidrome present? What are the treatment
priorities? What tests do you want to order?
17
Investigations

• Serum levels
• acetaminophen (4 hour level)
• ASA
• Ethanol
• ingestion specific (eg phenytoin, digoxin level)
• Electrolytes, BUN/Cr
• EKG
• Serum osmolarity

18
What about a Tox Screen?

• Urine immunoassays
• lab determines which tests to include on the
  screen
• Often clinically irrelevant
• confuse the clinical picture
• positive cocaine in a patient with an opioid
  toxidrome
• toxic TCA level in a cyclobenzaprine (Flexeril)
  overdose

Treat the patient, not the test!
19
Case
A 78 yo F presents with agitation and confusion.
BP 180/105, P 110 RR 16 T 38.2 C. Physical exam
reveals an acutely agitated pt, pupils 6 mm,
CVS/resp normal except tachycardia.
Is a toxidrome present? What are the treatment
priorities? What tests do you want to order?
20
Supportive treatment of the poisoned patient is
the cornerstone of management
21
A 20 yo F comes to the ED saying she just took a
whole bottle (1.5 grams) of Elavil
(amitriptylline). Her vital signs are normal.
She is alert and exam is normal.

• Treatment considerations?

22
Treatment

• Elimination
• Activated Charcoal
• Whole Bowel Irrigation
• Removal
• Gastric Lavage
• Antidotes

23
Treatment

• Elimination
• Activated Charcoal
• Whole Bowel Irrigation
• Removal
• Gastric Lavage
• Antidotes

24
Activated Charcoal

• Ingestion lt 1 hr
• upto 2 hrs if delayed emptying, bad toxin
• 1 g/kg or 10 g for each gram of OD drug
• Ineffective
• Pesticides
• Hydrocarbons
• Alcohols
• Iron
• Lithium
• Alkalis / acids (contraindicated)

25
Activated Charcoal

• CX
• Aspiration
• Gastric content aspiration worse than charcoal
  aspiration
• But a lot worse if dump charcoal into lungs
• Perforation if bowels not moving

26
Cathartics

• Sorbitol
• available premixed with charcoal
• can use for first dose
• contraindicated if lt 2 years
• electrolyte problems
• Used with charcoal to counteract its constipating
  effect

27
To Give or Not to Give...
An alert 36 year old M 2 hours post accidental
ingestion of antifreeze
28
To Give or Not to Give...
An alert 36 year old M 2 hours post accidental
ingestion of antifreeze
A Not indicated 2hrs is too late (esp for
liquid) and alcohols bind poorly
29
To Give or Not to Give...
A somnolent 45 yo F with ingestion of olanzapine
(Zyprexa) and venlafaxine (Effexor) at an
undetermined time.
30
To Give or Not to Give...
A somnolent 45 yo F with ingestion of olanzapine
(Zyprexa) and venlafaxine (Effexor) at an
undetermined time.
A Not indicated undetermined time (likely
greater than 1 hr for toxicity to develop from
these agents) and risk of aspiration given
altered mental status.
31
To Give or Not to Give...
An intubated 37 yo F 30 min after collapsed after
metoprolol OD.
32
To Give or Not to Give...
An intubated 37 yo F 30 min after collapsed after
metoprolol OD.
A Indicated recent ingestion, (very) bad drug
and airway is protected.
33
Treatment

• Elimination
• Activated Charcoal
• Whole Bowel Irrigation
• Removal
• Gastric Lavage
• Antidotes

34
Decontamination

• Gastric Lavage
• recent (lt 1hr)
• Life threatening ingestion
• no antidote
• not adsorbed by AC
• sustained release
• concretions
• no emesis

EasyLav
35
Gastric Lavage

• Large hose with blunt end (need this for tablets
  to pass)
• LL decubitus position with pylorus pointing
  upwards
• Has to have airway protected either intubated of
  fully conscious
• Have bucket of warm water and bucket on floor

36
Gastric Lavage

• Give warm water through funnel / tube above pt
  Percuss stomach move tube below level of head
  to drain into bucket repeat
• Prevents drug from getting into small intestine
  as drain directly from stomach

37
Treatment

• Elimination
• Activated Charcoal
• Whole Bowel Irrigation
• Removal
• Gastric Lavage
• Dialysis
• Antidotes

38
Whole Bowel Irrigation

• Polyethylene glycol (eg. Golytely)
• 1-2 L/hr via NGT until clear effluent
• Do for 4 to 6 hours until clear effluent via
  rectal tube
• SR preps, Lithium, iron, sustained release drugs
• Body packers/stuffers

39
A 20 yo F comes to the ED saying she just took a
whole bottle (1.5 grams) of Elavil
(amitriptylline). Her vital signs are normal.
She is alert and exam is normal.

• Treatment considerations?

40
Tricyclic Antidepressants - Sx

• Block sodium channels
• Neuro
• mental status changes
• anticholinergic toxicity
• seizures
• Cardiac
• (lethal) arrhythmias
• AV blocks
• hypotension
• QRS gt 120 ms and R in aVR gt 3mm predicts
  seizures/ arrhythmias

41
Tricyclic Antidepressants - Mgmt

• Activated Charcoal (no role for dialysis)
• Alkalinization of blood (7.45 7.50) with sodium
  bicarbonate
• Abolishes dysrhythmias and improves hypotension
• Use if QRS gt 100 msec
• Administer as 1 2 mEq/kg IV push then 20 mEq /
  hr drip

42
Enhanced Elimination

• Diuresis
• Alkaline
• 3 amps NaHCO3 in 1 L D5W with 40 mmol KCl at 250
  mL/hr
• goal urine pH 7.5-8
• E.g Salicylates, Phenobarbital
• Neutral
• Lithium

43
Tricyclic Antidepressants - Mgmt

• Seizure mgmt
• avoid dilantin (increases dysrhythmias)
• Diazepam/lorazepam/ phenobarbitol
• Hypotension
• Crystalloid and alkalinization
• Vasopressors if no response
• Dysrhythmias unresponsive to bicarb
• Lidocaine
• Consider pacemaker insertion for blocks

44
A 34 yo M presents 4 hours after ingesting 100
regular ASA pills. He complains of tinnitus, is
vomiting and has an ASA level of 6 mmol/L. His
vital signs are BP 132/78 P 85 RR 28 T 37.5 C

• Decontamination?Other treatment considerations?

45
Commonly Dialysable Drugs

• Isopropanol
• Salicylates
• Theophylline
• Uremia
• Methanol
• Barbiturates
• Lithium
• Ethylene Glycol

46
Salicylates - Symptoms

• Causes metabolic acidosis .. Initially resp
  alkalosis as stimulates resp centre
• Mild ototoxicity (tinnitis, vertigo)
• Severe CNS stimulation followed by depression
  (confusion, delerium, seizures_
• Cardiac dysrhythmias, noncardiogenic pulmonary
  edema, renal failure, hemorrhage

47
Salicylates Treatment

• Treatment is not dependant on specific serum
  level it is a CLINICAL diagnosis
• Done nomogram USELESS
• Draw levels to ensure declining

48
Salicylates Evaluation

• Decontamination with Activated charcoal
• Consider gastric lavage if lt 60 min
• Alkaline diuresis with bicarb increases
  elimination of ASA (goal of urine pH 5 8)
• See TCA OD for bicarb dosing
• Hemodialysis is most effective means
• Indications include renal failure, severe cardiac
  tox, rising ASA levels despite alkalinization,
  pulm edema, severe acidbase imbalance

49
Case
A 42 yo M presents after ingesting 30 grams of
acetaminophen. He is asymptomatic. A serum
level 4 hours after ingestion is 1625 ?mol/L.
50
Antidotes
Acetaminophen N-acetylcysteine
Atropine Physostigmine
Carbon monoxide oxygen
Cyanide Amyl nitrite sodium nitrite sodium thiosulfate
Ethylene glycol / Methanol Ethanol / fomepizole
Iron Deferoxamine
Lead EDTA (calcium disodium edetate)
51
Antidotes
Nitrites Methylene Blue
Organophosphate Atropine
Opiods Naloxone
Isoniazid Pyridoxine
Digoxim Digibind
Benzodiazepines Flumazenil
52
Acetaminophen

• Delayed hepatoxicity
• Consider activated charcoal
• Rumack-Matthew nomogram
• predicts toxicity 4 hrs after acute ingestion
• No use less than 4 hours before
• N-acetylcysteine antidote
• Minimum 300 mg/kg IV over 20 hrs
• Goal of therapy is administration of NAC within 8
  hrs of ingestion

53
(No Transcript)
54
Methanol

• Found in windshield washing fluid, paint
  thinners, solvents
• Converted by alcohol dehydrogenase to
  formaldehyde (liver) to formic acid
• Formic acid toxic product
• Causes high anion gap and osmole gap
• Affects optic nerve fxn causing papillitis and
  retinal edema blind drunk

55
High Anion Gap

• C (carbon monoxide, cyanide)
• A (Arsenic)
• T (toluene)
• M (methanol, metformin)
• U (uremia)
• D (DKA)
• P (paraldehyde, phenformin)
• I (INH, iron)
• L (Lactic acidosis)
• E (ethylene glycol (antifreeze), everything
• S (salicylates, strychtnine)

56
Anion and osmole gap

• AG Na Cl HCO3
• Osmole Gap 2Na BUN glucose ETOH( 1.25)
• Osmole gap causes
• Ethanol, Isopopanol, Methanol, Ethylene glycol,
  Acetone, Glycerol, Mannitol, Uremia,
  Ketocacidosis
• Isopropanol causes high osmole but not anion gap
• Peraldehyde and isoniazide cause high AG but not
  high osmole gap

57
Methanol

• 8 hour 30 hour latent period followed by onset
  of abdo pain, nausea, vomiting, blurred vision,
  metabolic acidosis
• Often dilated pupil with photophobia
• High anion gap acidosis
• Na Cl HCO3
• Osmole gap may be high but can be normal
• 2Na BUN glucose EtOH (1.25)
• Normal is 280 295 mosm

58
Methanol

• Supportive measures
• Consider bicarbonate with severe acidosis
• ADH inhibitor
• Fomepizole inhibits alcohol dehydrogenase
• Ethanol (BEER!) ethanol infusion as alcohol
  dehydrogenase preferentially metabolizes ethanol
  (keep at 22 33)
• Hemodialysis
• If symptomatic or methanol level gt 8 mmol / L
• Severe acidosis

59
TOXICOLOGY AXIOMS

• The most important aspect of the history is the
  time of ingestion and coingestants
• The most critical therapy varies with the time
  course of the patients presentation
• No evaluation is complete until repeated over
  time
• Toxidromes can help identify classes of drugs
• It is often not important to determine the exact
  drug taken within a class
• Supportive tx is the cornerstone of tx