Isopropanol

Isopropanol (isopropyl alcohol) causes the same effects as ethanol but is more potent. Commonly found in hand sanitisers, disinfectants, solvents, window cleaners and perfumes. Classically it causes an elevated osmolar gap without an anion gap and the patient smells of acetone. Fortunately care is largely supportive.

Toxic Mechanism:

The CNS effects are similar to ethanol with augmentation of GABAa causing CNS depression. Its metabolite acetone may contribute to CNS depression but does not cause a severe anion gap. Isopropanol is a GI irritant and in large doses can be a cardiovascular depressant.

Toxicokinetics: 

  • Rapid absorption, including dermal, inhalation as well as ingestion.
  • Volume of distribution is low (0.6 L/kg).
  • 40% is excreted unchanged in the lungs and kidneys. The rest is metabolised in the liver to acetone by alcohol dehydrogenase.
  • Acetone is mainly excreted in the lungs and to a lesser extent the kidneys (hence the acetone smell).

Resuscitation:

  • CNS depression: If there is any doubt over the patients ability to protect their own airway or you believe they are an aspiration risk they will require intubation and ventilation.

Risk Assessment

  • 1ml/kg of  a 70% isopropanol solution will cause inebriation. >4ml/kg may cause a coma and respiratory depression.
  • Co-ingestion with other CNS depressants increases the risk of respiratory depression.
  • A picture of intoxication will develop rapidly after ingestion
  • Ketosis may be present (acetone breath)
  • Loss of protective airway reflexes, respiratory depression and hypotension accompany coma.
  • Minor ingestions in children i.e. a small taste or a lick do not require evaluation unless symptoms are present. Usually develop within 2 hours.
  • Significant isopropanol toxicity has been reported in children from ‘rubbing alcohol’ causing a dermal exposure, used an an antipyretic.

Supportive Care

  • General supportive measures (i.e. IV fluids only if dehydrated), monitor for urinary retention.
  • If intubated see FASTHUGSINBED for further supportive care.
  • Thiamine 100mg TDS IV if no signs of Wernicke’s encephalopathy (Confusion, ataxia and ophthalmoplegia) otherwise 300mg TDS IV.

Investigations

  • Screening: 12 lead ECG, BSL, Paracetamol level
  • Specific:
    • EUC including chloride, serum osmolality, arterial blood gases and serum acetone.
      • Elevated osmolar gap in the absence of severe anion gap acidosis suggests isopropanol intoxication (Beware – this can occur in early ethylene glycol and methanol intoxication that either presents early or with co-ingestion of ethanol).
    • Urinalysis for ketones.

Decontamination:

  • Activated charcoal does not bind to alcohol

Enhanced Elimination

  • Haemodialysis is very effective but rarely indicated for isopropanol intoxication due to positive outcomes with supportive care.

Antidote

  • None available.

Disposition

  • Patients with mild CNS depression and signs of intoxication can be managed supportively on the ward and discharged when well.
  • Patients with significant CNS depression require intubation and intensive care.

References and Additional Resources:

Additional Resources:

Zeff – Gas analysis and osmolar gaps

References:

  • Stemski E, Hennes H. Accidental isopropanol ingestion in children. Paediatric Emergency Care 2000; 16(4):238-240
  • Zaman F, Pervez A, Abreu K. Isopropyl alcohol intoxication: a diagnostic challenge. American Journal of Kidney Diseases 2002; 40(3):E12

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Dr Neil Long BMBS FACEM FRCEM FRCPC. Emergency Physician at Burnaby Hospital in Vancouver. Loves the misery of alpine climbing and working in austere environments. Supporter of FOAMed, toxicology, tropical medicine, sim and ultrasound

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