Isopropyl alcohol toxicity: Difference between revisions

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== Background ==
==Background==
*Isopropyl alcohol acts directly as CNS depressant and is broken down by alcohol dehydrogenase to acetone, which further compounds effect
*Main component of rubbing alcohol
*Lethal Dose: 4-8 g/kg or 250mL in average adult
*Hallmark is osmolar gap, ketosis, that is without acidosis
**Metabolized to acetone, not to an acid
*Takes 30-60 min for acetone to appear in blood; 3 hr to appear in urine
*Lethal Dose: 4-8 g/kg or 250 mL in average adult (calculated using volume of pure isopropyl alcohol)
**Typical store bought rubbing alcohol is 70% isopropyl alcohol by volume, so lethal dose is ~ 350 mL


== Clinical Features ==
==Pharmacology<ref>Kraut JF, Kurtz I. Clin J Am Soc Nephrol 2008. PMID: 18045860</ref>==
*Symptoms of inebriation, disinhibition, sedation, and coma usually peak in the first hour of ingestion
*Unlike other toxic alcohols (methanol, ethylene glycol), toxic effects caused by parent agent (IA) rather than metabolite (acetone)
*"Fruity breath" can be seen as a result of acetone production
*Metabolized to acetone by alcohol dehydrogenase
*Maximal distribution in ≤ 2 hours
*Lethal dose > 200 mg/dL, although variable literature


== Work-Up ==
==Clinical Features==
*CNS depression
**Similar to ETOH intoxication, but longer-lasting
**Usually peaks in first hour of ingestion
*GI
**[[Nausea/vomiting]] / [[abdominal pain]] / hemorrhagic gastritis
*Respiratory depression
**Fruity breath from acetone
*[[Hypotension]], [[hypothermia]] from peripheral vasodilation
*[[Hypoglycemia]] (in malnourished patients)
 
==Differential Diagnosis==
*[[Starvation ketoacidosis]]
*[[Diabetic Ketoacidosis]]
*Inborn errors of metabolism
*[[Salicylate Toxicity]]
*Acetone ingestion
 
{{Sedatve/hypnotic toxicity types}}
 
==Evaluation==
===Work-Up===
*Fingerstick glucose
*Fingerstick glucose
*Complete metabolic panel
*Complete metabolic panel
*Serum ketones
*Serum ketones
*Serum Osmolality
*Serum Osmolality
*Uinarlysis
*Urinalysis
*VBG
*VBG
*Aspirin/Tylenol levels
*Aspirin/Tylenol levels
*ECG
*[[ECG]]
*Serum isopropyl alcohol level (if available)
*Serum isopropyl alcohol level (if available)
*Total CK
*Total CK


== Diagnosis ==
===Evaluation===
*Positive serum isopropyl alcohol level (if available)
*Osmolal gap > 10; see [[Osmolal or Osmolar Gap]]
*Osmolal gap > 10, see [[Osmolal or osmolar gap]]
*Absence of anion gap
*Absence of anion gap
*Absence of metabolic acidosis
*Absence of metabolic acidosis
*Absence of serum beta hydroxybutyrate
*Absence of serum beta hydroxybutyrate
*Presence of serum and urine ketones
*Presence of serum and urine ketones
**Consider other diagnosis if absent 2 hours after ingestion
**Consider other diagnosis if absent 2hr after ingestion
*Elevated creatinine may be falsely elevated as a result of acetone interference with laboratory measurement of creatinine
*Creatinine may be falsely elevated due to acetone interference with laboratory measurement of Cr
 
{{Toxic Alcohols Anion/Osmolar Gaps}}


== DDX ==
==Management==
*Ethanol ingestion
*Treatment is supportive.
*Methanol or ethylene glycol ingestion
*No role for fomepizole or ethanol
*Starvation ketoacidosis
**Blockade of alcohol dehydrogenase (ADH) will prolong intoxication
*Diabetic ketoacidosis
*Hemodialysis indications:
*Inborn errors of metabolism
**Hypotension
*Salicylate ingestion
**Comatose
*Acetone ingestion
**Consider if IA serum level >200mg/dL


== Treatment ==
==Disposition==
*Airway
*Generally may be discharged once clinically sober.
*Breathing
**Consider intubation to secure airway
*Circulation
**Fluid rehydration
*Minimal role in GI decontamination due to rapid absorption
**May consider nasogastric aspiration if done within 1 hour of ingestion
*Hemodialysis should be considered in persistently hypotensive patient after aggressive fluid hydration and vasopressor support or for Siopropyl levels greater than 400 mg/dL


== Disposition ==
==See Also==
*Unintentional ingestions may be safely discharged if asymptomatic after 2 hours of observation
*[[Toxic alcohols]]
*Any intentional ingestions should be screened for suicidal ideation and alcohol addiction
*[[In-Training Exam Review]]


== Source ==
==References==
Uptodate
<references/>


Rosen
[[Category:Toxicology]]

Latest revision as of 18:52, 20 February 2021

Background

  • Main component of rubbing alcohol
  • Hallmark is osmolar gap, ketosis, that is without acidosis
    • Metabolized to acetone, not to an acid
  • Takes 30-60 min for acetone to appear in blood; 3 hr to appear in urine
  • Lethal Dose: 4-8 g/kg or 250 mL in average adult (calculated using volume of pure isopropyl alcohol)
    • Typical store bought rubbing alcohol is 70% isopropyl alcohol by volume, so lethal dose is ~ 350 mL

Pharmacology[1]

  • Unlike other toxic alcohols (methanol, ethylene glycol), toxic effects caused by parent agent (IA) rather than metabolite (acetone)
  • Metabolized to acetone by alcohol dehydrogenase
  • Maximal distribution in ≤ 2 hours
  • Lethal dose > 200 mg/dL, although variable literature

Clinical Features

Differential Diagnosis

Sedative/hypnotic toxicity

Evaluation

Work-Up

  • Fingerstick glucose
  • Complete metabolic panel
  • Serum ketones
  • Serum Osmolality
  • Urinalysis
  • VBG
  • Aspirin/Tylenol levels
  • ECG
  • Serum isopropyl alcohol level (if available)
  • Total CK

Evaluation

  • Osmolal gap > 10; see Osmolal or Osmolar Gap
  • Absence of anion gap
  • Absence of metabolic acidosis
  • Absence of serum beta hydroxybutyrate
  • Presence of serum and urine ketones
    • Consider other diagnosis if absent 2hr after ingestion
  • Creatinine may be falsely elevated due to acetone interference with laboratory measurement of Cr

Toxic Alcohols Anion/Osmolar Gaps

Substance Osmolar gap Metabolic acidosis Anion gap Ketones Ca Oxalate crystals Reduced vision Management
Ethanol + +/- (if ketoacidosis) +/- (if ketoacidosis) +/- - - Mainly supportive
Ethylene glycol + (early)* + + - + - Fomepizole, Thiamine, Pyridoxine, +/- Dialysis
Methanol + (early)* + + - - + Fomepizole or ethanol, Folinic acid/Folic acid, +/- Dialysis
Isopropyl alcohol + - - + (acetonemia without acidosis) - - Mainly supportive, +/- Dialysis if severe
Propylene glycol + + + (lactic acidosis) - - - D/C offending agent (e.g. IV lorazepam/diazepam), supportive, +/- Dialysis
  • Osmolar gap → Anion gap transition: For all toxic alcohols, the osmolar gap is elevated early (parent compound present) and decreases over time as the alcohol is metabolized into organic acid metabolites, which then produce an anion gap metabolic acidosis. A normal osmolar gap does NOT exclude toxic alcohol ingestion if presentation is delayed.
Key distinguishing features
  • Isopropyl alcohol: The only toxic alcohol that causes ketosis without metabolic acidosis (metabolized to acetone, not an organic acid)
  • Ethylene glycol: Ca oxalate crystals in urine + anion gap metabolic acidosis + renal failure
  • Methanol: Visual disturbances (blurred vision, "snowfield" vision, blindness) + anion gap metabolic acidosis + optic disc hyperemia on fundoscopy

Management

  • Treatment is supportive.
  • No role for fomepizole or ethanol
    • Blockade of alcohol dehydrogenase (ADH) will prolong intoxication
  • Hemodialysis indications:
    • Hypotension
    • Comatose
    • Consider if IA serum level >200mg/dL

Disposition

  • Generally may be discharged once clinically sober.

See Also

References

  1. ↑ Kraut JF, Kurtz I. Clin J Am Soc Nephrol 2008. PMID: 18045860
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