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The Poisoned Patient: A Medical Student Review

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William Beaumont Hospital Department of Emergency Medicine. The Poisoned Patient: A Medical Student Review. Introduction. All chemicals, especially medicines, have the potential to be toxic 2006 TESS data 2.7 million exposures 19.8% were treated in a healthcare facility

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introduction
Introduction
  • All chemicals, especially medicines, have the potential to be toxic
  • 2006 TESS data
    • 2.7 million exposures
    • 19.8% were treated in a healthcare facility
    • 21.6% of those had more than minor outcomes including death
  • Over half of poisonings occur in kids < 5 yo
the initial approach
The Initial Approach
  • Always consider poisoning in differential diagnosis
  • IV, O2, monitor
  • Accucheck
  • D50 +/- thiamine or naloxone as indicated
  • Decontamination, protect yourself
  • Enhanced elimination
  • Antidotal therapy
  • Supportive care
history
History
  • Name, quantity, dose and route of ingestant(s)
  • Time of ingestion
  • Any co-ingestions
  • Reason for ingestion – accidental, suicidal
  • Other medical history and medications
  • EMS - inquire about scene, notes left, smells, unusual materials, pill bottles, etc.
pupils
Pupils
  • Dilated – anticholinergic, sympathomimetic
  • Constricted – cholinergic
  • Pinpoint – opiates
  • Horizontal nystagmus – ethanol, phenytoin, ketamine
  • Rotary or vertical nystagmus - PCP
slide6
Skin
  • Hyperpyrexia – anticholinergic, sympathomimetic, salicylates
  • Hypothermic – opiods, sedative-hypnotics
  • Dry skin – anticholinergics
  • Moist skin – cholinergics, sympathomimetics
  • Color – cyanosis, pallor, erythema
overall exam
Overall Exam
  • Stimulants – everything is UP
    •  temp, HR, BP, RR, agitated
    • Sympathomimetics, anticholinergics, hallucinogens
  • Depressants – everything is DOWN
    •  temp, HR, BP, RR, lethargy/coma
    • Cholinergics, opioids, sedative-hypnotics
  • Mixed effects: Polysubstance overdose, metabolic poisons (hypoglycemic agents, salicylates, toxic alcohols)
laboratory studies
Laboratory Studies
  • Accucheck
  • EKG
  • Chemistries (BUN, Cr, CO2)
  • UA – calcium oxalate crystals in ethylene glycol poisoning
  • Drugs of abuse & comprehensive screen
  • Acetaminophen, aspirin & ethanol levels
  • ABG, serum osmolality, toxic Alcohol screen, urine HCG and LFTS if warranted
general decontamination
General Decontamination
  • Remove all clothing
  • Wash away external toxic substances
    • If suspect transmittable contaminant, perform in decontamination area
  • If ocular exposure, flush eyes copiously with until pH 7 – 7.5
gi decontamination
GI Decontamination
  • Three methods
    • Gastric emptying
    • Bind the toxin in the gut
    • Enhance elimination
  • Always consider the patient’s mental status, risk of aspiration, airway security and GI motility before attempting any method
orogastric lavage
Orogastric Lavage
  • Indications
    • Life threatening ingestions
    • Present within one hour of ingestion
  • Studies show little benefit
    • May remove as little as 35% of the substance
    • Need secure airway
    • Relatively high complication rate
activated charcoal
Activated Charcoal
  • Absorbs toxin within the gut
  • 1 g/kg PO or via NG tube
  • Contraindications:
    • Bowel obstruction or perforation
    • Unprotected airway
    • Caustics and most hydrocarbons
    • Anticipated endoscopy
  • Not effective for alcohols, metals (iron, lead), or elements (magnesium, sodium, lithium)
multi dose activated charcoal
Multi-dose Activated Charcoal
  • Large doses of toxin
  • Slow release toxins
  • Enterohepatic or enterenteric circulation
  • Toxins that form bezoars
  • Used for: phenobarbital, theophylline, carbamazepine, dapsone, quinine
cathartics
Cathartics
  • 70% sorbitol 1g/kg PO
  • Administered with charcoal
  • Decreases transit time of both toxin and charcoal through the GI tract
  • Contraindications:
    • Children under 5 yo
    • Caustic ingestions
    • Possible bowel obstruction
whole bowel irrigation
Whole Bowel Irrigation
  • Go-Lytely via PO or NG tube at a rate of 2L/hr (500 mL/hr in peds)
  • Typically used for those substances not bound by activated charcoal
  • Contraindications:
    • Potential bowel obstruction
hemodialysis
Hemodialysis
  • Used for:
    • Salicylates
    • Methanol
    • Ethylene Glycol
    • Lithium
    • Isopropyl alcohol
  • Patients must be hemodynamically stable and without bleeding disturbances
toxin antidote
Toxin Antidote
  • Acetaminophen N-Acetylcysteine
  • Anticholinergic agent  Physostigmine
  • Benzodiazepines  Flumazenil
  • Beta blockers  Glucagon
  • Carbon monoxide  Oxygen
toxin antidote18
Toxin  Antidote
  • Cardiac glycosides  Digoxin-specific Fab
  • Cyanide  sodium nitrate, sodium thiosulfate, hydroxycobalamin
  • Ethylene glycol  Ethanol
  • Opiates  Naloxone
  • Organophosphates  Atropine, 2-PAM
  • Tricyclics  Sodium bicarb
case one
Case One

56 y/o male found unconscious in a basement. He has snoring respirations, frothing at the mouth, and rales on pulmonary exam. His pupils are pinpoint. He wakes up swearing and swinging at staff after a little narcan.

What could it be?

toxidrome opiates
Toxidrome: Opiates
  • Examples: heroin, morphine, fentanyl
  • Signs/Symptoms:
    • CNS depression, lethargy, confusion, coma, respiratory depression, miosis
    • Vital signs:  temp, HR, RR, +/- BP
    • Pulmonary edema, aspiration, resp arrest
    • Check for track marks, rhabdomyolysis, compartment syndrome
toxidrome opiates21
Toxidrome: Opiates
  • Treatment:
    • Naloxone 0.4 - 2 mg IV/IM/SC slowly
      • May result in severe agitation
      • Monitor closely and re-dose if necessary
toxidrome sympathomimetic23
Toxidrome: Sympathomimetic
  • Examples: cocaine, amphetamines (speed, dex, ritalin), phencyclidine (PCP), methamphetamines (crank, meth, ice), MDMA (ecstasy, X, E)
    • Stimulant: meth > amphetamines > MDMA
    • Hallucinogen: MDMA > meth > amphetamines
  • Signs/Symptoms:
    • Agitation,  temp, HR, BP, mydriasis
    • Seizures, paranoia, rhabdomyolysis, MI, arrhythmias, piloerection
toxidrome sympathomimetic24
Toxidrome: Sympathomimetic
  • Treatment:
    • Primarily supportive
      • Benzo’s, IV hydration, cooling if hyperthermic
    • Treat HTN with benzodiazepines or nitrates
    • Avoid beta blockers
  • Bodystuffers (small amt, poorly contained)
    • Asymptomatic - AC, monitor for toxicity
    • Symptomatic - AC, WBI, treat symptoms
  • Bodypackers (large amt, well contained)
    • Asymptomatic - WBI followed by imaging
    • Symptomatic - immediate surgical consult
toxidrome cholinergic26
Toxidrome: Cholinergic
  • Organophosphates
    • Insecticides, nerve gas (Sarin, Tabun, VX)
    • Irreversible binding to AChE – “aging”
  • Carbamates
    • Insecticides (Sevin)
    • Reversible binding to AChE – short duration
  • Examples: physostigmine, edrophonium, nicotine
  • All increase ACh at CNS, autonomic nervous system and neuromuscular junction
toxidrome cholinergic27
Toxidrome: Cholinergic
  • Signs/Symptoms:
    • SLUDGE Syndrome
      • Parasympathetic hyperstimulation
      • Salivation, Lacrimation, Urinary Incontinence, Defecation, GI pain, Emesis
    • Killer B’s
      • Bradycardia, Bronchorrhea, Bronchospasm
        • Bronchorrhea and respiratory failure is often the cause of death
    • Miosis, garlic odor,  MS, seizures, muscle fasciculations, weakness, respiratory depression, coma
toxidrome cholinergic28
Toxidrome: Cholinergic
  • Diagnosis: RBC or plasma cholinesterase level
  • Management:
    • Decontamination – protect yourself
    • Supportive therapy
    • Atropine - competitive inhibition of ACh
      • Large doses required
      • End point is the drying of secretions
    • Pralidoxime (2-PAM) - breaks OP-AChE bond
      • Start with 1-2 g IV over 30 minutes, give before “aging”
      • Adjust dose based on response, AChE level
case two
Case Two

22 y/o F presents with decreased urine output. She is febrile, confused, flushed and has dilated pupils on exam. You also notice a linear, vesicular rash on her lower legs.

What do you want to know?

case two30
Case Two
  • Meds
    • She has been using oral benadryl and topical caladryl lotion for the poison ivy

What is her toxidrome?

anticholinergic agents
Anticholinergic Agents
  • Antihistamines
    • Diphenhydramine, meclizine, prochlorperazine
  • Antipsychotics
    • Chlorpromazine (Thorazine), thiroidazine (Mellaril)
  • Belladonna alkaloids
    • Jimsonweed, atropine, scopolamine
  • Cyclic antidepressants
    • Amitriptyline, nortriptyline, fluoxetine
  • OTC’s
    • Excedrin PM, Actifed, Dristan, Sominex
  • Muscle relaxants
    • Orphenadrine, cyclobenzaprine
  • Amanita mushrooms
toxidrome anticholinergic
Toxidrome: Anticholinergic
  • Signs/Symptoms:
    • Dry as a bone – lack of sweating
    • Red as a beet – flushed, vasodilated
    • Hot as hades – hyperthermia
    • Blind as a bat – mydriasis
    • Mad as a hatter – delirium, hallucinations
    • Stuffed as a pipe – hypoactive bowel sounds, ileus, decreased GI motility, urinary retention
    • VS:  temp, HR, BP
toxidrome anticholinergic33
Toxidrome: Anticholinergic
  • Rule out psychiatric disorders, DTs, sympathomimetic toxicity
  • Management:
    • Sedation with benzodiazepines
    • Temp control
    • Treat wide QRS and dysrhythmias with bicarb
    • Physostigmine
      • Use only in clear cut cases
      • Monitor for excess cholinergic response - SLUDGE
toxidrome salicylates35
Toxidrome: Salicylates
  • Examples: aspirin, oil of wintergreen, OTC remedies
  • Signs/Symptoms:
    • Altered mental status
    • Tinnitus
    • Nausea and vomiting
    • Tachycardia
    • Tachypnea (Kussmaul respirations)
    • Hyperthermia
toxidrome salicylates36
Toxidrome: Salicylates
  • Diagnosis:
    • Metabolic acidosis and respiratory alkalosis
    • Anion gap
    • Salicylate level > 30mg/dL
toxidrome salicylates37
Toxidrome: Salicylates
  • Treatment:
    • Multi-dose AC
    • Alkalinize urine
    • HD if levels > 100 mg/dl, altered MS, renal failure, pulmonary edema, severe acidosis or hypotension
toxidrome serotonin syndrome39
Toxidrome: Serotonin Syndrome
  • Examples: SSRI’s, MAOI’s, meperidine, tricyclics, trazadone, mertazapine, dextromethorphan, LSD, lithium, buproprion, tramadol
  • May be caused by any of the above, but usually occurs with a combination of agents, even if in therapeutic doses
toxidrome serotonin syndrome40
Toxidrome: Serotonin Syndrome
  • Signs/Symptoms:
    • Altered MS, mydriasis, myoclonus, hyperreflexia, tremor, rigidity (especially lower extremities), seizures, hyperthermia, tachycardia, hypo or hypertension
    • Citalopram and escitalopram - prolonged QT and QRS
  • No confirmatory test – diagnosis based on clinical suspicion
toxidrome serotonin syndrome41
Toxidrome: Serotonin Syndrome
  • Treatment:
    • Supportive care
    • Single dose AC (ensure airway control)
    • Benzodiazepines to treat discomfort, muscle contractions or seizures
    • Cooling measures
    • Treat prolonged QT with magnesium
    • Treat widened QRS with bicarb
    • Cyproheptadine (anti-serotonin agent)
acetaminophen poisoning43
Acetaminophen Poisoning
  • Signs/Symptoms:
    • Stage I: 0-24 hrs
      • Nausea, vomiting, anorexia
    • Stage II: 24-72 hrs
      • RUQ pain, elevation of AST and ALT, also elevation of bilirubin and PT if severe poisoning
    • Stage III: 72-96 hrs
      • Peak of AST, ALT, bilirubin and PT, possible renal failure and pancreatitis
    • Stage IV: > 5 days
      • Resolution of hepatotoxicity or progression to multisystem organ failure
acetaminophen poisoning44
Acetaminophen Poisoning
  • Rummack-Mathew nomogram
  • Acetaminophen levels vs. time
  • Plot 4 hr level
  • Useful for single acute ingestion only
acetaminophen poisoning45
Acetaminophen Poisoning
  • Management:
    • AC, assume polypharmacy OD
    • NAC - N-acetylcysteine (NAC)
      • Ingested over 140 mg/kg OR toxic level on nomogram
      • Draw baseline LFTs and PT
      • IV or PO dose
case three
Case Three

17 y/o M brought in by family for acting “drunk.” He is lethargic, confused, disoriented. Vitals: 130, 90/60, 16, 37 C.

Labs: ETOH 0, CO2 12

What else do you want to know?

case three47
Case Three

Accucheck: 102

Serum osmolality: 330

Na 140, K 4.0, Cl 100, CO2 12, glucose 90

BUN 28, Cr 2.0

UDS, APAP, ASA are all negative

UA has calcium oxalate crystals

What are we hinting at?

toxic alcohols
Toxic Alcohols
  • Typical Agents
    • Ethanol
    • Isopropanol
    • Methanol
    • Ethylene glycol (EG)
toxic alcohols49
Toxic Alcohols
  • All toxic alcohols cause an osmolar gap
  • Methanol, ethanol and ethylene glycol cause an anion gap acidosis
    • M – methanol
    • U – uremia
    • D – DKA
    • P – paraldehyde, propylene glycol
    • I – iron, isoniazid
    • L – lactic acid
    • E – ethanol, ethylene glycol
    • S – salicylates
useful equations
Useful Equations
  • Anion Gap (mEq/L)

Na - (Cl + HCO3)

  • Calculated Osmolarity (mosm/L)

2Na + BUN/2.8 + Glu/18 + ETOH/4.6

toxic alcohols isopropanol
Toxic Alcohols: Isopropanol
  • Examples: rubbing alcohol, antifreeze, disinfectants
  • Second most commonly ingested alcohol
  • Isopropyl alcohol has twice the CNS depressing potency and up to 4 times the duration as ethanol
  • Metabolized by alcohol dehydrogenase to acetone
toxic alcohols isopropanol53
Toxic Alcohols: Isopropanol
  • Signs/Symptoms:
    • Fruity breath
    • Appear intoxicated
    • Nausea, vomiting, abdominal pain
    • Hypotension
    • Respiratory depression  coma
  • Lab abnormalities
    • Ketonuria
    • Osmolar gap
    • Normal pH, no acidosis
toxic alcohols methanol55
Toxic Alcohols: Methanol
  • Examples: paint removers, antifreeze, windshield washer fluid, bootleg liquor
  • Metabolized to toxic formaldehyde and formic acid
  • Can cause permanent retinal injury and blindness as well as parkinsonian syndrome if not treated promptly
  • May have a long latent period (12 to 18 hours), especially if co-ingested with ethanol
toxic alcohols methanol56
Toxic Alcohols: Methanol
  • Signs/Symptoms:
    • Lethargy, nausea, vomiting, abd pain
    • Visual symptoms seen in 50% - blurring, tunnel vision, color blindness
    •  HR, RR, BP
    • CNS - headache, seizures or coma
  • Lab abnormalities
    • Wide anion-gap metabolic acidosis
    • Osmolar gap
    • Toxic alcohol screen to confirm
toxic alcohols ethylene glycol58
Toxic Alcohols: Ethylene Glycol
  • Examples: antifreeze
  • Seen with alcoholics, suicide attempts and children
  • Colorless, odorless and sweet
  • Is rapidly absorbed and converted to toxic acids responsible for clinical signs and symptoms
  • Treatment similar to methanol
toxic alcohols ethylene glycol59
Toxic Alcohols: Ethylene Glycol
  • Signs/Symptoms:
    • 1-12 hours – CNS depression
      • Inebriation, vomiting, seizures, coma, tetany (hypocalcemia)
    • 12-24 hours – cardiopulmonary phase
      • hypotension, tachydysrhythmias, tachypnea and ARDS
    • 24-72 hours – nephrotoxic phase
      • Oliguric renal failure, ATN, flank pain, calcium oxylate crystalluria
toxic alcohols ethylene glycol60
Toxic Alcohols: Ethylene Glycol
  • Lab and EKG abnormalities:
    • Hypocalcemia secondary to precipitation with oxylate, excreted as urinary calcium oxylate crystals
    • Urine may also fluoresce secondary to fluorescence dye in antifreeze
    • EKG: QT prolongation (hypocalcemia) and peaked T’s (hyperkalemia)
    • Myalgias, secondary to acidosis and elevated CPK
toxic alcohols ethylene glycol61
Toxic Alcohols: Ethylene Glycol

Always consider EG in an inebriated patient without alcohol breath, with an anion-gap metabolic acidosis, osmolar gap and calcium oxylate crystalluria

treatment of eg and methanol
Treatment of EG and Methanol
  • Supportive, especially airway
  • Correct acidosis with bicarb, 1meq/kg IV
  • Benzo’s if seizure
  • Folic acid 50mg IV q 4 hrs for both
  • Ca gluconate 10 ml of 10% IV – to correct hypocalcemia – EG only
treatment of eg and methanol63
Treatment of EG and Methanol
  • Block production of toxic metabolites
    • Ethanol – IV or PO
    • Fomepizole - preferred method
      • Has 8000 times the affinity for ADH as ETOH without CNS depression and hypoglycemia
treatment of eg and methanol64
Treatment of EG and Methanol
  • Hemodialysis indicated if:
    • Serum level > 50 mg/dl
    • Signs of nephrotoxicity (EG) or CNS or visual disturbances (methanol)
    • Severe metabolic acidosis
tricyclics66
Tricyclics
  • Agents:
    • Amitriptyline (Elevil), desipramine (Norpramin), imipramine (Tofranil) and nortriptyline (Pamelor)
  • Narrow therapeutic index
  • Have returned to popularity with non-depression indications such as chronic pain, migraines, ADHD and OCD
tricyclics67
Tricyclics
  • Signs/Symptoms:
    • CNS – decreased LOC
      • Confusion, hallucinations, delirium, seizures
    • Cardiovascular – arrhythmias and hypotension
      • QRS > 100 msec, conduction delays
      • Arrhythmias such as V-tach & torsades may develop as QRS widens and QT prolongs
    • Anticholinergic toxidrome
      • Tachycardia, mydriasis, hyperthermia, anhydrosis, urinary retention, decreased bowel sounds
tricyclics68
Tricyclics
  • EKG during TCA toxicity and after treatment with bicarb. Note wide QRS, prolonged QT and terminal R’s > 3mm in AVR
tricyclic overdose treatment
Tricyclic Overdose Treatment
  • AC
  • Na Bicarb – to treat QRS prolongation > 100 msec and hypotension refractory to IV fluids
  • Benzo’s to treat seizures and hyperthermia
  • Magnesium and lidocaine for ventricular arrythmias refractory to bicarb
  • Magnesium for QT prolongation or Torsades
carbon monoxide71
Carbon Monoxide
  • Sources:
    • Fossil fuel combustion (car exhaust), smoke, kerosene or coal heaters, steel foundries
  • CO binds to hemoglobin with 230 times the affinity to oxygen, decreasing it’s ability to transport oxygen
carbon monoxide72
Carbon Monoxide
  • Signs/Symptoms:
    • Nausea, malaise, headache, decreased mental status, dizziness, paresthesias, weakness, syncope
    • May progress to vomiting, lethargy, coma, seizures, CVA , MI or respiratory arrest
  • Need a high index of suspicion – multiple family members with flu like symptoms without fever, winter months
carbon monoxide73
Carbon Monoxide
  • COHb level may not represent the severity of the poisoning
  • Pulse oximetry also may be misleading
  • Half-life of COHb
    • 4 hours on room air
    • 60 minutes breathing 100% normobaric O2
    • 15 to 23 minutes breathing 100% hyperbaric O2
carbon monoxide treatment
Carbon Monoxide Treatment
  • 100% O2 via NRB for 4 hrs minimum if mild symptoms (nausea, heachache, malaise)
carbon monoxide treatment75
Carbon Monoxide Treatment
  • 100% O2 + HBO if any of the following:
    • Altered mental status or coma
    • History of LOC or near syncope
    • History of seizure
    • Hypotension during or after exposure
    • MI
    • Pregnant with COHb > 15%
    • Arrythmias
    • +/- COHb > 25-40%