Isopropyl Alcohol Poisoning

Aka: Isopropyl Alcohol Poisoning, Isopropanol Ingestion, Isopropanol Intoxication, Isopropyl Alcohol, Isopropranol, Rubbing Alcohol, Isopropranol Toxicity

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II. Background

  1. Isopropanol (Isopropyl Alcohol, Rubbing Alcohol) is the most common Toxic Alcohol ingestion in the U.S.
    1. Other Toxic Alcohol ingestions include Ethylene Glycol Poisoning, Methanol Poisoning

III. Pathophysiology

  1. Isopropanol is absorbed rapidly from the Gastrointestinal Tract
  2. Isopropanol is converted to acetone in the liver by Alcohol dehydrogenase
  3. Acetone is a Ketone Body that has no charge (neutral)
    1. Results in Ketosis without a Metabolic Acidosis or Anion Gap
    2. Osmolal Gap is increased (as with other Toxic Alcohol ingestions)

IV. Pharmacokinetics

  1. Effects (and plasma levels) peak 1 hour after ingestion
  2. Half-Life of isopropanol: 2.5 to 16 hours (typically <8 hours)
  3. Half-Life of acetone: 7 to 26 hours (typically >10 hours)
  4. Renal excretion of both isopropanol (up to 50% not metabolized) and acetone
  5. Lethal dose Isopropyl Alcohol: 250 ml (significant illness may occur with as little as 10 ml ingestion)
    1. However, even children have survived much larger ingestions with supportive care alone

V. Sources

  1. Rubbing Alcohol (accounts for 70% of product)
  2. Hand Cleansers
  3. Perfume solvents
  4. Paint thinners
  5. Cleaners and disinfectants
  6. Racing fuel

VI. Findings

  1. Similar Intoxication effects as with Alcohol Intoxication
    1. Acute Gastritis is common with Isopropyl Alcohol
    2. Isopropyl Alcohol is a more potent intoxicant than Alcohol
  2. Neurologic Changes
    1. Altered Level of Consciousness (CNS Depression)
      1. Drowsiness or Lethargy
      2. Coma
    2. Headache
    3. Ataxia
    4. Decreased Deep Tendon Reflexes (or areflexia)
  3. Associated findings
    1. Fruity breath odor (acetone)
    2. Vomiting
    3. Hypotension (myocardial depression)
    4. Tachycardia
    5. Hypothermia
    6. No visual effects (unlike the Retinopathy associated with Methanol)
  4. Severe shock findings in massive ingestion
    1. Hematemesis (Hemorrhagic Gastritis)
    2. Pulmonary Edema
    3. Pulmonary Hemorrhage

VII. Labs

  1. See Unknown Ingestion for full workup
  2. Complete Blood Count
    1. Aplastic Anemia
    2. Hemolytic Anemia
  3. Serum Glucose
    1. Hyperglycemia
  4. Serum Electrolytes and Renal Function tests
    1. Serum Creatinine falsely elevated when acetone levels >40-100 mg/dl (colorimetric testing)
    2. Suspect false Serum Creatinine elevation if the Blood Urea Nitrogen and the Blood pH are normal
    3. Unlike Ethylene Glycol, Isopropyl Alcohol does not cause Renal Failure
    4. Unlike Ethylene Glycol and Methanol, does not cause Metabolic Acidosis with Anion Gap (unless Alcoholic Ketoacidosis)
  5. Serum Ketones
    1. Beta Hydroxybutyrate elevation is NOT due to Isopropyl Alcohol ingestion (acetone)
    2. Beta Hydroxybutyrate elevation typically indicates other Ketosis causes (e.g. Diabetic Ketoacidosis)
  6. Creatinine Kinase
    1. Elevated in Rhabdomyolysis
  7. Serum Osmolality
    1. Osmolar Gap with Isopropyl Alcohol as well as other Toxic Alcohols (Methanol, Ethylene Glycol)
    2. Osmolar Gap rises 16.6 mmol/L for each serum Isopropyl Alcohol level of 100 mg/dl
  8. Venous Blood Gas
    1. No Metabolic Acidosis despite Ketosis
    2. Contrast with Metabolic Acidosis with Anion Gap with other Toxic Alcohol ingestions (Methanol, Ethylene Glycol)
  9. Isopropanol Level (serum Isopropyl Alcohol level)
    1. Send-out lab in most hospitals
    2. Level >50 mg/dl: Toxic effects
    3. Level >150 mg/dl: Risk of death (without supportive care)
    4. Level >400 mg/dl: Consider Hemodialysis
  10. Acetone Levels
    1. Send-out lab in most hospitals

VIII. Differential Diagnosis

  1. Critical to exclude other, far more Toxic Alcohol ingestions (Ethylene Glycol, Methanol)
    1. See Unknown Ingestion
    2. See Altered Level of Consciousness
  2. Ingestions
    1. Alcohol Intoxication
    2. Other Toxic Alcohol Ingestion (cause Metabolic Acidosis with Anion Gap)
      1. Methanol Poisoning
      2. Ethylene Glycol Poisoning
  3. Other Ketoacidosis causes
    1. Diabetic Ketoacidosis
    2. Euglycemic Ketoacidosis (e.g. SGLT2 Inhibitor)
    3. Alcoholic Ketoacidosis
    4. Starvation Ketosis
    5. Inborn Errors of Metabolism (branched-chain ketonuria, propionic acidemia)
    6. Salicylate Toxicity

IX. Management

  1. ABC Management and supportive care
  2. Fomepizole (Alcohol Dehydrogenase inhibition) is NOT indicated (unlike with other Toxic Alcohol ingestions)
  3. Activated Charcoal may be considered in recent ingestion (esp. for other co-ingestions)
    1. Isopropyl Alcohol absorption is so rapid, GI Decontamination is unlikely to be of benefit
  4. Hemodialysis Indications
    1. Course refractory to supportive care
    2. Serum Isopropyl Alcohol level >400-500 mg/dl

X. Complications: Acute

  1. CNS Depression related acute complications
    1. Airway compromise
  2. Rhabdomyolysis
  3. Cardiovascular Depression and shock

XI. Prognosis

  1. Ethylene Glycol Intoxication has twice the acute lethality of Alcohol Intoxication, although fatalities are rare
  2. However, if patient survives the acute Intoxication, there are no significant longterm complications

XII. References

  1. (2019) Isopropyl Alcohol , UpToDate, accessed online 7/13/2019
  2. Leikin (1996) Poisoning and Toxicology Handbook, 2nd ed, Lexicomp, p. 943-4
  3. Tagliaferro (2023) Crit Dec Emerg Med 37(1): 21-9

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