Basics
Description
- Poisoning may be intentional or unintentional.
- Patients with change in mental status without clear cause should have poisoning (intoxication, overdose) considered in differential diagnosis.
Etiology
- Intentional:
- Depression
- Suicide
- Homicide
- Recreational drug abuse
- Unintentional (accidental):
- Common cause in children
- Therapeutic error (e.g., double dose)
- Recreational drug experimentation
- Accidental ingestions " typically young children (1 " 5 yr)
- Consider child abuse if inconsistent or suspicious history.
Diagnosis
Signs and Symptoms
- Neurologic:
- Lethargy
- Agitation
- Coma
- Hallucinations
- Seizures
- Respiratory:
- Tachypnea, bradypnea, apnea
- Inability to protect airway
- Cardiovascular:
- Dysrhythmias
- Conduction blocks
- Vital signs:
- Varies depending on toxic substance
- Hyperthermia, hypothermia
- Tachycardia, bradycardia
- Hypertension, hypotension
Selected Toxidromes (seePoisoning, Toxidromes)
- Anticholinergic:
- Altered mental status (confusion, delirium, lethargy)
- Dry skin and mucous membranes
- Fixed dilated pupils
- Tachycardia
- Hyperthermia
- Flushing
- Urinary retention
- Cholinergic:
- Secretory overdrive (salivation, lacrimation, urination, diaphoresis)
- Miosis
- Bronchospasm, wheezing
- Opiate:
- CNS and respiratory depression
- Miosis
- Sympathomimetic:
- CNS excitation
- Seizures
- Tachycardia
- Hypertension
- Diaphoresis
Essential Workup
- A complete set of vital signs, including core temperature
- A complete physical exam, including eyes, skin, odors
Diagnosis Tests & Interpretation
Lab
- Electrolytes, BUN/creatinine, glucose
- Calculate anion gap: Na + (Cl + HCO3):
- Normal anion gap: 8 " 12
- Use mnemonic A CAT MUD PILES for elevated anion gap acidosis:
- Alcoholic ketoacidosis
- Cyanide, carbon monoxide
- Aspirin, other salicylates
- Toluene
- Methanol, metformin
- Uremia
- Diabetic ketoacidosis
- Paraldehyde, phenformin
- Iron, isoniazid
- Lactic acidosis from other causes
- Ethylene glycol
- Starvation ketosis
- Serum osmol gap:
- Calculate osmol gap if elevated anion gap acidosis from potential toxic alcohol.
- Most sensitive early in poisoning
- Normal osmol gap does not completely rule out toxic alcohol ingestion.
- Calculated osmolality = 2(Na+) + glucose/18 + BUN/2.8 + ethanol (in mg/dL)/4.6.
- Osmol gap = measured osmolality " calculated osmolality.
- Use mnemonic ME DIE A when osmol gap >10:
- Methanol
- Ethanol
- Diuretics (mannitol, glycerin, sorbitol)
- Isopropyl alcohol
- Ethylene glycol
- Acetone
- Pregnancy test
- Acetaminophen level for suicidal ingestions
- Toxicology screen
Imaging
- ECG for dysrhythmias or QRS/QT changes
- CT of head for altered mental status not clearly due to toxin
- Chest radiograph if suspected aspiration or pneumonia
Differential Diagnosis
- Causes of altered mental status
- Intracranial mass, bleeding
- Infection, sepsis
- Endocrine abnormalities
- Hypothermia
- Hypoxia
- Metabolic abnormalities
- Psychogenic
Treatment
Pre-Hospital
- Search for clues at scene:
- Pills/pill bottles
- Drug paraphernalia
- Witnesses
- Transport all drugs and pill bottles for identification.
- Restrain uncooperative patients for patient and health care giver protection.
- Consider comorbid conditions:
- Trauma
- Medical illness
- Environmental exposure
- Pre-hospital administration of activated charcoal may optimize decontamination if prolonged transport time.
Initial Stabilization/Therapy
- ABCs:
- Endotracheal intubation as needed for airway protection, oxygenation, ventilation, and orogastric lavage
- Supplemental oxygen for hypoxia
- Pulse oximetry
- Cardiac monitor
- IV access
- Hypotension:
- Administer 0.9% normal saline IV fluid bolus.
- Trendelenburg
- Vasopressors for persistent hypotension
- Bradycardia:
- If altered mental status, administer coma cocktail: Thiamine, D50W (or Accu-Chek), naloxone
Ed Treatment/Procedures
- Decontamination:
- See Poisoning, Gastric Decontamination.
- Prevents systemic absorption of ingested toxin
- Orogastric lavage:
- Consider in potentially lethal ingestions without known antidote within 1 hr of ingestion.
- Protected airway essential prior to lavage
- Activated charcoal:
- Most effective within a few hours of most toxic ingestions
- Contraindicated if caustic ingestion, unprotected airway, or bowel obstruction
- Drugs not effectively bound to charcoal: Metals (borates, bromide, iron, lithium), alcohols, potassium
- Whole-bowel irrigation:
- Polyethylene glycol (Colyte, GoLytely) evacuates bowel without causing electrolyte disturbances.
- Consider in toxins not well adsorbed by charcoal (e.g., iron and lithium), body packers/stuffers, sustained-release ingestions.
- Contraindicated if bowel obstruction, perforation, or hypotension
- Enhanced elimination:
- Enhances removal of systemically absorbed toxin
- Multiple-dose activated charcoal:
- Theophylline
- Carbamazepine
- Phenobarbital
- Urinary alkalinization:
- Hemodialysis/hemoperfusion:
- Lithium
- Salicylates
- Theophylline
- Toxic alcohols
- Valproate
- Seizures
- Treat initially with diazepam or lorazepam.
- For persistent seizures, consider phenobarbital.
- Phenytoinnot indicated in toxicologic seizures:
- Indicated only if seizures secondary to idiopathic epilepsy, post-traumatic, or status epilepticus
- Antidotes:
- Acetaminophen: N-acetylcysteine
- Anticholinergic: Physostigmine
- Benzodiazepines: Flumazenil
- ²-blockers: Glucagon
- Calcium-channel blockers: Calcium chloride/gluconate, insulin
- Carbon monoxide: Oxygen, hyperbaric oxygen
- Coumadin: Vitamin K1
- Cyanide: Cyanide antidote kit, hydroxocobalamin
- Digoxin: Digibind
- Ethylene glycol: Ethanol, 4-methylpyrazole
- Iron: Deferoxamine
- Isoniazid: Pyridoxine (vitamin B6)
- Methanol: Ethanol, 4-methylpyrazole
- Methemoglobinemia: Methylene blue
- Opiates: Naloxone
- Organophosphates: Atropine, pralidoxime
- Tricyclic antidepressants: NaHCO3
Medication
- Activated charcoal slurry: 1 " 2 g/kg PO
- Dextrose: D50W 1 amp: 50 mL or 25 g (peds: D25W 2 " 4 mL/kg) IV
- Diazepam: 5 " 10 mg (peds: 0.2 " 0.5 mg/kg) IV every 10 " 15 min
- Lorazepam: 2 " 6 mg (peds: 0.05 " 0.1 mg/kg) IV every 10 " 15 min
- Naloxone (Narcan): 0.4 " 2 mg (peds: 0.1 mg/kg) IV or IM initial dose
- Thiamine (vitamin B1): 100 mg (peds: 50 mg) IV or IM
Follow-Up
Disposition
Admission Criteria
- Altered mental status
- Cardiopulmonary instability
- Suicidal
- Lab abnormalities
- Potential for decompensation from delayed acting substance
Discharge Criteria
- Psychiatrically clear
- Detoxified
- Hemodynamically stable
Issues for Referral
- Patients with unintentional (accidental) poisoning require poison prevention counseling.
- Patients with intentional (e.g., suicide) poisoning require psychiatric evaluation.
- Consider substance abuse referral for patients.
In general, treating the mother is also the best treatment strategy for the fetus.
Follow-Up Recommendations
- Consider substance abuse referral for patients with recreational drug abuse.
- Patients with unintentional (accidental) poisoning require poison prevention counseling.
- Patients with intentional (e.g., suicide) poisoning require psychiatric evaluation.
Pearls and Pitfalls
- Do not forget to consider nontoxicologic etiologies for altered mental status.
- Do not rely on the urine drug screen to make a diagnosis: It only provides screening tests for a limited number of drugs.
- Call a toxicologist or a poison center for help: 800-222-1222.
Additional Reading
- Erickson TB, Thompson TM, Lu JJ. The approach to the patient with an unknown overdose. Emerg Med Clin North Am. 2007;25(2):249 " 281.
- Levine M, Brooks DE, Truitt CA, et al. Toxicology in the ICU: Part 1: General overview and approach to treatment. Chest. 2011;140(3):795 " 806.
- Mycyk MB. Poisoning and drug overdose. In: Longo D, Fauci A, Kasper D, et al., eds. Harrisons Principles of Internal Medicine. 18th ed. New York, NY: McGraw Hill; 2012:e50.1 " e50.16.
- Wills B, Erickson T. Drug- and toxin-associated seizures. Med Clin North Am. 2005;89:1297 " 1321.
See Also (Topic, Algorithm, Electronic Media Element)
- Poisoning, Antidotes
- Poisoning, Gastric Decontamination
- Poisoning, Toxidromes
Codes
ICD9
- 971.1 Poisoning by parasympatholytics (anticholinergics and antimuscarinics) and spasmolytics
- 977.9 Poisoning by unspecified drug or medicinal substance
- 977.9 Poisoning by unspecified drug or medicinal substance
- 977.9 Poisoning by unspecified drug or medicinal substance
- 971.0 Poisoning by parasympathomimetics (cholinergics)
- 971.2 Poisoning by sympathomimetics [adrenergics]
- 969.6 Poisoning by psychodysleptics (hallucinogens)
- 965.00 Poisoning by opium (alkaloids), unspecified
ICD10
- T44.3X1A Poisoning by oth parasympath and spasmolytics, acc, init
- T65.91XA Toxic effect of unspecified substance, accidental (unintentional), initial encounter
- T65.91XA Toxic effect of unspecified substance, accidental (unintentional), initial encounter
- T65.91XA Toxic effect of unspecified substance, accidental (unintentional), initial encounter
- T44.1X1A Poisoning by oth parasympath, accidental, init
- T65.92XA Toxic effect of unspecified substance, intentional self-harm, initial encounter
- T44.901A Poisn by unsp drugs aff the autonm nervous sys, acc, init
- T65.93XA Toxic effect of unspecified substance, assault, initial encounter
- T40.901A Poisoning by unsp psychodyslept, accidental, init
- T65.94XA Toxic effect of unsp substance, undetermined, init encntr
- T40.601A Poisoning by unsp narcotics, accidental, init
SNOMED
- 216593002 Accidental poisoning by anticholinergics (disorder)
- 75478009 Poisoning (disorder)
- 75478009 Poisoning (disorder)
- 75478009 Poisoning (disorder)
- 235453002 selective decontamination of the digestive tract (procedure)
- 61356009 Poisoning by parasympathomimetic drug (disorder)
- 67329000 Administration of antidote (procedure)
- 72431002 Accidental poisoning (disorder)
- 410061008 Intentional poisoning (disorder)
- 45536007 poisoning by sympathomimetic drug (disorder)
- 269736006 Poisoning of undetermined intent (disorder)
- 85975005 Poisoning by psychodysleptic (disorder)
- 11196001 Poisoning by opiate AND/OR related narcotic (disorder)
- 271982007 Intentional self poisoning (disorder)