Isopropanol Poisoning, Emergency Medicine

Basics

Description

CNS depressant effect of isopropanol is 2 to 3 times as potent as that of ethanol.
Many products that contain isopropanol also contain methanol, ethylene glycol, and ethanol.
Rapidly absorbed following oral ingestion
Ketogenic, but does not cause significant acidosis
Metabolized by alcohol dehydrogenase to acetone (a CNS depressant):
- Concomitant ethanol ingestion doubles half-life of isopropanol but not that of acetone.
- Acetone eliminated by lung and kidney
Half-life:
- Isopropanol: 3 " 16 hr
- Acetone: 7.5 " 26 hr

Etiology

Isopropanol (isopropyl alcohol): Clear, colorless, volatile liquid with faint odor of acetone and bitter taste
Available as 70% rubbing alcohol solution:
- May contain blue dye that was added to inhibit its abuse ( "blue heaven " )
Found in:
- Various toiletries
- Disinfectants
- Window-cleaning solutions
- Paint remover
- Solvents
- Jewelry cleaners
- Detergents
- Antifreeze
- Hand sanitizers
Typical adult patient: Chronic alcoholic who has been on drinking binge and recently depleted his or her ethanol supply
Dermal and rectal administration can cause systemic toxicity.

Diagnosis

Signs and Symptoms

Usually occur within 30 " 60 min of ingestion
Neurologic:
- Lethargy
- Weakness
- Headache
- Inebriation
- Vertigo
- Ataxia
- Apnea
- Coma
- Initial excitation phase seen with ethanol ingestion is absent.
GI:
- Nausea/vomiting
- Abdominal pain
- Gastritis
- Hematemesis
Cardiovascular:
- Hypotension
- Tachycardia
- Myocardial depression
- Peripheral vascular dilation
Pulmonary:
- Respiratory depression
- Hemorrhagic tracheobronchitis
Dermatologic:
- Skin irritation
- Burns
Ocular:
- Irritation
- Lacrimation

Accidental ingestions common in <6-yr olds.
Rubbing alcohol sponge baths may cause inhalational toxicity.

Essential Workup

History of ingestion
Odor of isopropanol or acetone on patients breath

Diagnosis Tests & Interpretation

Lab

Electrolytes, BUN, creatinine (Cr), glucose:
- Hypoglycemia occurs.
- Does not produce significant acidosis unless accompanied by end-organ hypoperfusion.
- Acetone can produce false elevation of serum Cr:
  - When acetone level >40 mg/dL, Cr values rise at ¢ ¼1 mg Cr/100 mg/dL acetone.
  - Cr returns to baseline following acetone metabolism.
CBC:
- Decreased hematocrit with significant hemorrhagic gastritis
Arterial blood gas:
- Acidosis rare unless owing to hypoperfusion or coingestant.
Urinalysis:
- Ketones present.
Serum ketones are present.
Isopropanol level:
- Coma with level >150 mg/dL
Serum osmolarity:
- Osmolar gap: Difference between measured and calculated osmolarity
- Calculated osmolarity = 2 Na+ BUN/2.8 + glucose/18 + ethanol/4.6.
- Osmolar gap is present if measured minus calculated osmolality is >10.
- Gap increases by 1 mOsm/kg for each 5.9 mg/dL of isopropanol and 5.5 mg/dL of acetone.

Imaging

CXR: For aspiration pneumonia with altered mental status and vomiting
CT head: Concomitant head injury occurs.

Differential Diagnosis

For CNS depression and elevated osmolar gap includes:
- Ethanol
- Ethylene glycol
- Methanol
- Glycerol
- Mannitol

Prone to hypoglycemia following exposure

Treatment

Pre-Hospital

Search for and transport all bottles and medications that may have been ingested by the patient when an overdose is suspected.

Initial Stabilization/Therapy

ABCs:
- Maintain airway and assist in ventilation if necessary.
Hypotension:
- Treat initially with 0.9% NS IV fluid bolus.
- Initiate dopamine or norepinephrine infusion if hypotension persists.
- Packed RBCs with significant hemorrhagic gastritis
Place NG tube and irrigate for patients with hematemesis.
Naloxone, thiamine, dextrose (or Accu-Chek) if altered mental status

Ed Treatment/Procedures

Primarily supportive therapy " no specific antidote
Irrigate skin/eyes for dermal or ocular exposure.
Consider activated charcoal:
- For coingestants
- Large doses can absorb significant amounts of isopropanol.
Do not treat with ethanol infusion or 4-methylpyrazole.
Hemodialysis:
- Effectively removes isopropanol and acetone.
- Most managed with supportive care alone.
- Indications:
  - Hemodynamic instability despite fluid replacement and use of pressors
  - Levels >400 mg/dL (associated with severe hypotension and prolonged coma)

Medication

Activated charcoal slurry: 1 " 2 g/kg up to 90 g PO
Dextrose: D50W 1 amp: 50 mL or 25 g (peds: D25W 2 " 4 mL/kg) IV
Dopamine: 2 " 20 mg/kg/min IV
Naloxone (Narcan): 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
Moderate to severe isopropanol toxicity (altered mental status, hypotension)
Discharge Criteria

Observe asymptomatic patients following ingestion for 2 " 4 hr before discharge.
Mild intoxication that resolves over 4 " 6 hr

Issues for Referral
GI referral for endoscopy for patients with recurrent hematemesis.

Followup Recommendations

Alcohol detox or psychiatry referral for patients with intentional ingestion

Pearls and Pitfalls

Supportive care is the primary treatment.
Do not treat with ethanol infusion or 4-methylpyrazole.

Additional Reading

Emadi A, Coberly L. Intoxication of a hospitalized patient with an isopropanol-based hand sanitizer. N Engl J Med. 2007;356:530 " 531.
Kraut JA, Kurtz I. Toxic alcohol ingestions: Clinical features, diagnosis, and management. Clin J Am Soc Nephrol. 2008;3:208 " 225.
Smith JC, Quan D. Chapter 179: Alcohols. Tintinallis Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw-Hill; 2011.

Codes

ICD9

976.0 Poisoning by local anti-infectives and anti-inflammatory drugs
980.2 Toxic effect of isopropyl alcohol
982.8 Toxic effect of other nonpetroleum-based solvents

ICD10

T51.2X1A Toxic effect of 2-Propanol, accidental (unintentional), initial encounter
T52.8X1A Toxic effect of organic solvents, accidental, init

SNOMED

216645001 Accidental poisoning by isopropyl alcohol (disorder)
212813006 Toxic effect of isopropyl alcohol

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