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The Poisoned Patient: A Medical Student Review

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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The Poisoned Patient: A Medical Student Review

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  1. William Beaumont Hospital Department of Emergency Medicine The Poisoned Patient:A Medical Student Review

  2. 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

  3. 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

  4. 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.

  5. Pupils • Dilated – anticholinergic, sympathomimetic • Constricted – cholinergic • Pinpoint – opiates • Horizontal nystagmus – ethanol, phenytoin, ketamine • Rotary or vertical nystagmus - PCP

  6. Skin • Hyperpyrexia – anticholinergic, sympathomimetic, salicylates • Hypothermic – opiods, sedative-hypnotics • Dry skin – anticholinergics • Moist skin – cholinergics, sympathomimetics • Color – cyanosis, pallor, erythema

  7. 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)

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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)

  13. 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

  14. 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

  15. 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

  16. Hemodialysis • Used for: • Salicylates • Methanol • Ethylene Glycol • Lithium • Isopropyl alcohol • Patients must be hemodynamically stable and without bleeding disturbances

  17. Toxin Antidote • Acetaminophen N-Acetylcysteine • Anticholinergic agent  Physostigmine • Benzodiazepines  Flumazenil • Beta blockers  Glucagon • Carbon monoxide  Oxygen

  18. 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

  19. 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?

  20. 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

  21. Toxidrome: Opiates • Treatment: • Naloxone 0.4 - 2 mg IV/IM/SC slowly • May result in severe agitation • Monitor closely and re-dose if necessary

  22. Toxidrome: Sympathomimetic

  23. 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

  24. 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

  25. Toxidrome: Cholinergic

  26. 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

  27. 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

  28. 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

  29. 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?

  30. Case Two • Meds • She has been using oral benadryl and topical caladryl lotion for the poison ivy What is her toxidrome?

  31. 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

  32. 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

  33. 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

  34. Toxidrome: Salicylates

  35. Toxidrome: Salicylates • Examples: aspirin, oil of wintergreen, OTC remedies • Signs/Symptoms: • Altered mental status • Tinnitus • Nausea and vomiting • Tachycardia • Tachypnea (Kussmaul respirations) • Hyperthermia

  36. Toxidrome: Salicylates • Diagnosis: • Metabolic acidosis and respiratory alkalosis • Anion gap • Salicylate level > 30mg/dL

  37. Toxidrome: Salicylates • Treatment: • Multi-dose AC • Alkalinize urine • HD if levels > 100 mg/dl, altered MS, renal failure, pulmonary edema, severe acidosis or hypotension

  38. Toxidrome: Serotonin Syndrome

  39. 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

  40. 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

  41. 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)

  42. Acetaminophen Poisoning

  43. 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

  44. Acetaminophen Poisoning • Rummack-Mathew nomogram • Acetaminophen levels vs. time • Plot 4 hr level • Useful for single acute ingestion only

  45. 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

  46. 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?

  47. 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?

  48. Toxic Alcohols • Typical Agents • Ethanol • Isopropanol • Methanol • Ethylene glycol (EG)

  49. 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

  50. Useful Equations • Anion Gap (mEq/L) Na - (Cl + HCO3) • Calculated Osmolarity (mosm/L) 2Na + BUN/2.8 + Glu/18 + ETOH/4.6

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