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A. Agents

  1. Ethanol (EtOH)
  2. Isopropanol
  3. Methanol (MeOH)
  4. Ethylene Glycol

B. Determination of Alcohol Levels

  1. Most patients with EtOH ingestion should be suspected of additional agent ingestions
  2. Measure serum osmolality (Osm) to estimate presence of unmeasured agents
  3. Serum Osm = Unmeasured Osm + 2·[Na+] + [BUN mg/dL]/2.8 + [Glucose mg/dL]/18
    1. EtOH Osm = EtOH mg/dL ÷ 4.3
    2. Isopropanol Osm = Isopropanol mg/dL ÷ 5.9
    3. MeOH Osm = MeOH mg/dL ÷ 2.6
  4. Obtain serum osm (experimental) from chemistry laboratory
    1. Calculate Unmeasured Osm = measured Osm - calculated Osm
    2. Estimate alcohol content from above conversions
    3. Once EtOH level is known, check calculated EtOH Osm
    4. If Unmeasured Osm > EtOH Osm, then suspect another agent

C. EtOH Intoxication

  1. Airway protection with intubation in patients with depressed mental status
  2. Gastric Lavage (typically with Ewald Tube)
  3. Charcoal usually not helpful because EtOH is rapidly absorbed
  4. Hemodialysis may be needed in life-threatening intoxications
  5. Thiamine 100mg iv followed by glucose infusion
    1. Many alcoholics are chronically malnourished
    2. Glucose given prior to thiamine may precipitate Wernicke's Encephalopathy
    3. Folate 1-2mg iv often given with thiamine
  6. Observation / Hydration of patient until EtOH level <100mg/dL
  7. Consider giving course of benzodiazapines to ease withdrawal
    1. Serax® 15-30mg q4-6 hrs with taper over several days
    2. Ativan® 1-2mg iv/im/po q4-6 hrs to inpatients
    3. Librium® 50-100mg q6 hrs with taper over several days
    4. Benzodiazepines given as needed (rather than regularly) may be better tolerated

D. Methanol Ingestion

  1. Found in gas-line antifreeze, windshield washer fluid
  2. Pathophysiology
    1. Methanol (MeOH) itself is not very toxic
    2. MeOH metabolized to formaldehyde (HCHO) by alcohol dehydrogenase (AlcDH)
    3. HCHO is metabolized to formic acid (HCOOH) by formaldehyde dehydrogenase
    4. HCHO causes protein dysfunction (acts as a tissue "fixative")
    5. HCOOH causes metabolic acidosis and tissue injury
  3. Symptoms and Laboratory Tests
    1. Tachypnea
    2. Visual Problems
    3. Severe Metabolic Acidosis from HCOOH production
  4. Toxic Ingestion 15-400mL; MeOH level should be estimated from osmolal gap
  5. Therapy [3]
    1. Gastric Lavage and Charcoal Administration
    2. Folinic Acid (1mg/kg iv) + Folic Acid 1mg/kg intravenous (IV) every four hours for 6 doses
    3. These vitamins increase formate catabolism
    4. Glucose, electrolytes and fluids as needed
    5. Fomepizole is an AlcDH inhibitor and is safe and effective
    6. Fomepizole is given 15mg/kg loading dose, then 10mg/kg bolus q12 hours as needed
    7. Ethanol (EtOH) IV infusion can be used in MeOH level >20mg/dL
    8. Hemodialysis
  6. Indications for Hemodialysis [3]
    1. Arterial pH <7.1
    2. Decrease in arterial pH >0.05 or reduction in serum bicarbonate >5 mmol/L
    3. MeOH level >50mg/dL
    4. Decline in serum MeOH level <10mg/dL per 24 hours

E. Isopropanol Ingestion

  1. Intoxication occurs at 50mg/dL, stupor and coma >100mg/dL
  2. Ketosis (metabolism to acetone) without Acidosis
  3. Therapy
    1. Hydration
    2. Maintain airway and blood pressure
    3. Hemodialysis for patients with hypotension

F. Ethylene Glycol Poisoning [2]

  1. Antifreeze and Winshield Deicer
    1. Metabolized by alcohol dehydrogenase to glycoaldehyde and glycolic acid
    2. Glycolic acid then metabolized to glyoxylic acid then to oxalic acid
    3. Glycoaldehyde, glycolic acid, and glyoxylic acid are toxic
    4. As little as 120mg/kg (0.1mL/kg) body ethylene glycol can lead to 20mg/dL in serum
    5. This level can be very toxic
  2. Symptoms
    1. Similar to EtOH with ataxia, mental status changes
    2. Signs and sypmtoms within 30 minutes following ingestion
    3. Nausea, vomiting, slurred speech, ataxia, nystagmus, lethargey common
    4. Faint sweet aromatic odor may be detected on breath
  3. Laboratory Tests
    1. Severe metabolic acidosis with anion gap
    2. Hypocalcemia
    3. Hyperkalemia
    4. Oxalate crystals in urine (oxaluria)
    5. Renal failure may occur
    6. Congestive heart failure with pulmonary edema 12-36 hours post-ingestion
    7. Central nervous system damage including seizures, coma
  4. Treatment [3]
    1. Supportive therapy
    2. Sodium bicarbonate (NaHCO3) IV to correct acidosis - large amounts
    3. Emesis; lavage within 30 min of ingestion
    4. Charcoal followed by non-Mg laxative
    5. EtOH infusion (to level 100-125mg/dL) for glycol level >20mg/dL or metablic acidosis
    6. Fomepizole, an inhibitor of alcohol dehydrogenase is effective and safe
    7. Fomepizole does not cause the problems with intoxication (see above)
    8. Pyridoxine 100mg iv and thiamine 100mg iv
    9. Dialysis in severe cases until resolution of symptoms and signs of disease
  5. Prognosis
    1. Corresponds fairly well to severity of symptoms and laboratory abnormalities
    2. Poor correlation with ethylene glycol levels
    3. Severe acidosis, hyperkalemia, seizures and coma on admission are poor prognostic signs

Resources

calcpH Henderson-Hasselbalch

References

  1. Brent J, McMartin K, Phillips S, et al. 2001. NEJM. 344(6):425
  2. Takayesu JK, Bazari H, Linshaw M. 2006. NEJM. 354(10):1065 (Case Record) abstract
  3. Brent J, McMartin K, Phillips S, et al. 1999. NEJM. 340(11):832 abstract