Which toxins can cause a sensation of intoxication similar to alcohol intoxication?

Toxins That Cause Alcohol-Like Intoxication

Carbon monoxide is the most critical toxin to consider when a patient presents with a "drunk-like" sensation, as it causes headache, dizziness, confusion, and impaired coordination that closely mimics alcohol intoxication but can be rapidly fatal if missed. 1

Primary Toxins to Consider

Carbon Monoxide (Most Important)

Carbon monoxide poisoning presents with symptoms that directly mimic alcohol intoxication 1:

• At COHb levels 15-20%: Headache, dizziness, fatigue
• At COHb levels 20-30%: Pounding headache, visual disturbances, irritability, impaired coordination (the "drunk" feeling)
• At COHb levels 30-40%: Severe weakness, nausea, vomiting, confusion or delirium
• Higher levels: Progress to seizures, coma, and death

Critical pitfall: Standard pulse oximetry readings will be falsely normal because it cannot distinguish carboxyhemoglobin from oxyhemoglobin 1. You must obtain COHb levels via co-oximetry on arterial blood gas.

Key diagnostic clue: Multiple people in the same household or enclosed space presenting with similar "drunk-like" symptoms, especially during heating season or with faulty appliances 1.

Toxic Alcohols

Several toxic alcohols produce intoxication-like symptoms 2, 3, 4:

Methanol (found in solvents, fuel, adulterated alcoholic drinks):

• Initially causes intoxication similar to ethanol
• Progresses to headache, nausea, vomiting, visual disturbances (including blindness)
• Metabolites (formaldehyde, formic acid) cause the severe toxicity 5

Ethylene glycol (antifreeze):

• Early phase mimics alcohol intoxication
• Progresses to metabolic acidosis and renal failure
• Toxicity from metabolites, not the parent compound 6, 4

Isopropyl alcohol (rubbing alcohol):

• Causes intoxication without the severe metabolic acidosis of methanol/ethylene glycol
• Presents with hyperosmolality alone 4

Diagnostic approach for toxic alcohols: Look for high anion gap metabolic acidosis combined with elevated osmol gap 2, 4. However, timing matters—if you see the patient late, the alcohol may be metabolized (normal osmol gap) but acidosis persists.

Cyanide and Hydrogen Sulfide

These chemically asphyxiating agents can present with CNS depression and confusion that mimics intoxication 1:

• Cause rapid cellular energy failure
• Present with collapse, seizures, cardiovascular instability, and severe lactic acidosis
• Critical context: Suspect in fire victims or industrial exposures, especially if pH <7.2 and lactate >10 mmol/L despite oxygen therapy 7, 1

Algorithmic Approach to Diagnosis

Step 1: Assess exposure context

• Enclosed space, heating season, multiple victims → Think CO
• History of ingesting unknown liquid, "moonshine," or antifreeze → Think toxic alcohols
• Fire or industrial exposure → Consider CO + cyanide

Step 2: Obtain critical labs immediately

• Arterial blood gas with co-oximetry (for COHb)
• Basic metabolic panel (anion gap)
• Serum osmolality (calculate osmol gap)
• Lactate level
• Do NOT rely on pulse oximetry 1

Step 3: Pattern recognition

• Elevated COHb → CO poisoning
• High anion gap + high osmol gap → Toxic alcohol (early)
• High anion gap + normal osmol gap → Toxic alcohol (late) or other causes
• Severe acidosis (pH <7.2) + lactate >10 mmol/L despite oxygen → Consider cyanide 7, 1

Immediate Management Priorities

For suspected CO poisoning 1:

• Remove from source immediately
• Administer 100% oxygen via non-rebreather mask at 8-12 L/min
• Do not wait for laboratory confirmation
• Consider hyperbaric oxygen for severe cases

For toxic alcohols 6:

• Fomepizole (or ethanol if fomepizole unavailable) to block alcohol dehydrogenase
• Hemodialysis for severe cases
• Supportive care for acidosis

For cyanide (if suspected) 7:

• Hydroxocobalamin is the specific antidote
• Indicated when pH <7.2 or lactate ≥10 mmol/L in fire victims despite oxygen therapy

Common Pitfalls

1. Assuming normal pulse oximetry rules out CO poisoning—it does not 1
2. Missing CO in chronic smokers—they have baseline COHb of 5-12%, masking mild poisoning 1
3. Dismissing the diagnosis because COHb doesn't correlate with symptoms—brief high-concentration exposures can cause severe symptoms at moderate COHb levels 1
4. Failing to consider coingestions—44% of intentional poisonings involve multiple substances, with 66% including ethanol 7
5. Missing the timing window for osmol gap in toxic alcohols—it normalizes as the parent alcohol is metabolized 4