Acute alcohol intoxication is a toxic metabolic and neuro-depressant state caused by ingestion of toxic alcohols including:

• Ethanol (beverage alcohol)

• Methanol (industrial alcohol)

• Ethylene glycol (antifreeze)

The condition results in central nervous system depression, metabolic derangements, and multi-organ injury depending on the compound ingested.

Unlike ethanol intoxication (usually self-limiting), methanol and ethylene glycol poisoning are true medical emergencies because their toxic metabolites cause:

Toxicity occurs due to metabolism by alcohol dehydrogenase (ADH) → accumulation of organic acids → severe metabolic acidosis.

2. Pathophysiology

Ethanol

• Enhances GABA inhibitory neurotransmission

• Inhibits NMDA glutamate receptors

• Causes CNS depression → coma → respiratory arrest

Methanol

Methanol → formaldehyde → formic acid

Formic acid causes:

• Retinal toxicity → blindness

• Basal ganglia necrosis

• Severe metabolic acidosis

Ethylene glycol

Ethylene glycol → glycolic acid → oxalic acid

Oxalate crystals deposit in:

• Kidneys → acute renal failure

• Brain → coma

• Heart → arrhythmias

3. Risk Factors

Exposure related

• Accidental ingestion (children)

• Suicide attempt

• Consumption of illicit alcohol

• Industrial exposure

• Adulterated spirits

Patient related

• Alcohol dependence

• Psychiatric illness

• Homelessness

• Poverty / limited access to safe alcohol

• Chronic liver disease

• Malnutrition

• Diabetes

• Chronic kidney disease

4. Clinical Stages

Ethanol intoxication stages

Methanol poisoning stages

1. Latent phase (6–24 hrs)

2. Metabolic acidosis

3. Visual toxicity → blindness

Ethylene glycol poisoning stages

1. CNS depression (0–12 hr)

2. Cardiopulmonary toxicity (12–24 hr)

3. Renal failure (24–72 hr)

5. Signs and Symptoms

General

• Nausea

• Vomiting

• Abdominal pain

• Confusion

• Euphoria

• Slurred speech

• Ataxia

• Altered level of consciousness

Severe toxicity

• CNS depression

• Hypothermia

• Airway compromise

• Respiratory depression

• Hypotension

• Seizures

• Coma

Metabolic abnormalities

• Hypoglycaemia

• Hypokalaemia

• Metabolic acidosis

• Renal failure

Specific findings

6. Diagnostic Criteria

Diagnosis is clinical + laboratory based.

Suspect toxic alcohol ingestion if:

• Altered mental status

• High anion gap metabolic acidosis

• Osmolar gap > 10

• Visual symptoms

• Renal failure without clear cause

7. Investigations

Essential

• Blood glucose

• Serum electrolytes

• Urea & creatinine

• Arterial blood gas

• Serum osmolarity

• Serum ethanol level

• ECG

Confirmatory

• Methanol level

• Ethylene glycol level

• Serum ketones

• Urinalysis (calcium oxalate crystals)

• CT brain (if coma)

Calculate gaps

Anion gapNa – (Cl + HCO₃)

Osmolar gapMeasured osmolality − calculated osmolality

8. Management

⚠️ Medical emergency — treat immediately if suspected (do NOT wait for levels)

8.1 Initial Resuscitation (ABC)

Airway

• Airway protection

• Intubation if GCS ≤ 8

Breathing

• Oxygen therapy

• Mechanical ventilation if needed

Circulation

• IV fluids

• Treat hypotension

8.2 Non-Pharmacological Treatment

• Insert urinary catheter

• Nasogastric tube (aspiration prevention)

• Temperature control

• Continuous cardiac monitoring

• Hemodialysis if severe poisoning

8.3 Antidote Therapy

FIRST LINE: Fomepizole

Blocks alcohol dehydrogenase → prevents toxic metabolite formation

Dose

• Loading: 15 mg/kg IV over 30 min

• Then: 10 mg/kg every 12 hrs × 4 doses

• Then: 15 mg/kg every 12 hrsContinue until toxic alcohol < 20 mg/dL

Alternative: Ethanol therapy

Competes with toxic alcohol for metabolism

Adults

Loading600 mg/kg IV(≈7.6 mL/kg of 10% ethanol)

OR oral diluted ethanol ≤20%

Maintenance155 mg/kg/hrMaintain serum ethanol 100–150 mg/dL

Increase dose:

• Chronic alcohol users

• Hemodialysis patients

Children

Oral loading

• 95% ethanol: 0.8–1 mL/kg

• 40% ethanol: 2 mL/kg

• 43% ethanol: 1.8 mL/kg

Maintenance0.1 mL/kg/hr orally or IV equivalent

Continue until level < 10 mg/dL

8.4 Adjunctive Therapy

For metabolic acidosis

• IV sodium bicarbonate

Methanol poisoning

• Folinic acid / folic acid (enhances formate metabolism)

Ethylene glycol poisoning

• Thiamine

• Pyridoxine

8.5 Indications for Hemodialysis

• Severe acidosis (pH < 7.3)

• Visual symptoms

• Renal failure

• Electrolyte imbalance

• Toxic alcohol level > 50 mg/dL

• Deteriorating clinical status

9. Complications

• Blindness (methanol)

• Acute kidney injury (ethylene glycol)

• Brain damage

• Aspiration pneumonia

• Cardiac arrest

• Death

10. Special Populations

Children

• Rapid hypoglycaemia

• Small ingestion → severe toxicity

Chronic alcohol users

• Need higher antidote dose

• Risk of withdrawal

Pregnant women

• Severe fetal toxicity

• Dialysis early

11. Prevention

Public health

• Regulation of industrial alcohol

• Control illicit brewing

• Poison labeling

Clinical counseling

• Avoid unknown alcohol

• Safe storage at home

• Mental health referral for suicidal ingestion

12. Prognosis

Early fomepizole + dialysis → survival >95%