Unknown Ingestion

Aka: Unknown Ingestion, Toxin Ingestion, Medication Overdose, Poisoning

1. History (Mnemonic: History MATtERS)
   1. Materials or Medications
   2. Amount or concentration
   3. Time taken
   4. Emesis
   5. Reason
   6. Signs and Symptoms
2. Exam: Focus areas
   1. Toxin Induced Vital Sign Changes
   2. Toxin Induced Skin Changes
   3. Toxin Induced Neurologic Changes
   4. Toxin Induced Odors
   5. Pupil changes (Miosis, Mydriasis, and pupil reactivity)
      1. Also see Eye Examination Signs of Chemical Dependency
3. Evaluation: Mass Casualty Exposure
   1. Consider Exposure possibilities
      1. Biological Weapon
      2. Chemical Weapon
   2. Mnemonic: Asbestos
      1. Agents
         1. Type and toxicity of agent
         2. Potential Lethality of exposure
      2. State
         1. Solid or Liquid
         2. Gas, Vapor, or Aerosol
         3. State combination
      3. Body Site
         1. Where exposure occurred
         2. Routes of entry and absorption
      4. Effects
         1. Local
         2. Systemic
      5. Severity
         1. Mild, moderate or severe effects and exposure
      6. Time course
         1. Past: When did symptom onset occur
         2. Present: Getting better or worse?
         3. Future: Prognosis
      7. Other diagnoses
         1. Differential diagnosis
         2. Additional or combination diagnoses
      8. Synergism
         1. Combined effects of multiple exposures
4. Causes
   1. See Accidental Poisoning Causes
5. Labs
   1. Complete Blood Count
   2. Basic Chemistry Panel (Chem8)
      1. Anion Gap calculation is critical
   3. Arterial Blood Gas (ABG)
   4. Serum Osmolality
   5. Urinalysis
   6. Urine Tox Screen (Urine superior to blood)
   7. Urine Pregnancy Test (if indicated)
   8. Carboxyhemoglobin (Obtain immediately if Carbon Monoxide Poisoning suspected)
   9. Drug Levels in all overdose cases
      1. Serum Aspirin Level (obtain 6-12 hours after ingestion)
      2. Serum Acetaminophen Level (obtain 4 hours after ingestion; also consider at 2 hours)
      3. Blood Alcohol level (obtain 0.5 to 1 hour after ingestion)
   10. Drug levels when indicated
       1. Serum Theophylline Level
       2. Serum Digoxin Level (obtain 2-4 hours after ingestion)
       3. Serum Amitriptyline Level
       4. Serum Iron level (obtain 2-4 hours after ingestion)
6. Labs: Red Flags
   1. Metabolic Acidosis with elevated Anion Gap
   2. Elevated Osmolar Gap
7. Diagnostics: Electrocardiogram (esp. if Tricyclic Antidepressant or Antipsychotic overdose suspected)
   1. Obtain serial EKGs during emergency department evaluation
   2. Monitor continuous telemetry
   3. Findings suggestive serious cardiotoxicity (and risk of Ventricular Tachycardia or Torsades)
      1. Prolonged QT interval
      2. Wide QRS
      3. Tall R Wave (or Terminal R Wave) in AVR
8. Differential Diagnosis: Toxidromes
   1. Cholinergic Toxicity
   2. Anticholinergic Toxicity
   3. Sympathomimetic Toxicity
   4. Serotonin Syndrome
   5. Beta Blocker Overdose
   6. Calcium Channel Blocker Overdose
   7. Clonidine Overdose
   8. Acetaminophen Overdose
   9. Salicylate Overdose (Salicylism)
   10. Sulfonylurea Overdose
   11. Tricyclic Antidepressant Overdose
   12. Opioid Overdose (Narcotic Overdose)
   13. Benzodiazepine Overdose
   14. Drug Withdrawal
   15. Club Drug or Date Rape Drug
   16. Chemical Dependency
       1. Opioids
       2. Hallucinogen
       3. Alcohol Abuse
       4. Amphetamine
       5. Benzodiazepine Abuse
       6. CNS Depressants
       7. Cocaine
       8. Volatile Inhalants
       9. Marijuana
       10. Phencyclidine
9. Imaging
   1. Chest XRay
      1. Chemical pneumonitis
      2. Toxin Induced pulmonary edema
      3. Pneumothorax
   2. Abdominal XRay (KUB)
      1. See Radiopaque Toxins
10. Management
    1. Consider Toxin Antidotes
    2. Consider Gastric Decontamination with charcoal if presentation within 1-2 hours of poison ingestion
       1. Charcoal given within 30 minutes after ingestion: Decreases absorption by 70%
       2. Charcoal given within 30-60 minutes after ingestion: Decreases absorption by 30%
       3. Do not use Gastric Lavage
    3. Consider Decontamination
       1. Protect medical personnel
          1. Liquid toxin
          2. Vapor off-gassing from patient
       2. Protect patient from further injury
    4. Consider Hemodialysis (for drugs cleared by Dialysis)
    5. Supportive Care
       1. ABC Management
       2. Appropriate hydration
       3. Rapid Sequence Intubation
          1. Rocuronium is preferred paralytic in ingestions
          2. Risk of Hyperkalemia (which would contraindicate Succinylcholine)
             1. Overdosage with ACE Inhibitors or Digoxin
             2. Rhabdomyolysis associated with unconscious from overdose
    6. QRS Widening on EKG
       1. Sodium Bicarbonate 1-2 ampules IV push
11. References
    1. Chu (2002) Am J Respir Crit Care Med 166(1):9-15
    2. Erickson (2007) Emerg Med Clin North Am 25(2):249-81
    3. Frithsen (2010) Am Fam Physician 81(3): 316-23
    4. Henry (2006) Pediatr Clin North Am 53(2): 293-315
    5. Mokhlesi (2003) Chest 123(2):577-92
    6. Nicholson (1983) Med Clin North Am 67(6):1279-93