EM Toxicology 15: Ethanol

Question 1

Remarks on alcohols

Answer 1

All alcohols cause clinical inebriation, with the strength of inebriating effects directly proportional to the alcohol’s molecular weight; hence, at the same concentration, isopropanol is more intoxicating than ethanol

ethanol and isopropanol are themost common alcohols ingested

Question 2

differentiate ethanol & isopropanol vs methanol & ethylene glycol

Answer 2

Ethanol & Isopropanol
- primary toxicity is due to parent compound
- principal effects are GI irritation and intoxication
- do not in themselves produce a clinically relevant metabolic acidosis

Methanol & Ethylene Glycol
- primary toxicity is due to toxic metabolites
- toxic alcohols because they cause serious multi-system damage and metabolic acidosis

Question 3

most frequently used and abused drug in the world

Answer 3

ethanol
- blood levels peak about 30-60 mins after ingestion
- presence of food in the stomach prolongs absorption and delays the peak blood levels

Question 4

what may account for the fact that women usually develop a higher blood ethanol level than men after consuming the same dose per kilogram of body weight?

Answer 4

higher levels of gastric alcohol dehydrogenase in men than in women

This enzyme breaks down ethanol in the stomach, thereby lowering the amount available for absorption

Question 5

death may occur in nonhabituated individuals at what concentrations

Answer 5

400-500 mg/dL
(death from respiratory depression)

Question 6

impairment in driving a motor vehicle may occur with levels as los as

Answer 6

50 mg/dL, especially in nonhabituated individuals

Question 7

remarks on metabolism of ethanol

Answer 7

major enz: alcohol dehydrogenase
at high ethanol conc’n: CYP2E1

Both alcohol dehydrogenase and CYP2E1 are inducible and thus are more active in chronic ethanol users. Therefore, rates of ethanol elimination from the blood vary from
15-20 mg/dL/hour in nonhabituated
**30 mg/dL/hour **in those with chronic alcoholism

Question 8

hallmark of ethanol toxicity

Answer 8

clinical inebriation

Question 9

mechanism of ethanol as CNS depressent

Answer 9

Enhances GABA receptors
Blocks NMDA receptors

Modulation of these systems leads to the development of tolerance, dependence, and a withdrawal syndrome

Question 10

explain hypoglycemia and lactic acidosis in ethanol ingestion

Answer 10

1. The metabolism of ethanol by alcohol dehydrogenase requires the presence of the oxidized form of nicotinamide adenine dinucleotide (NAD+), which is then converted to its reduced form (NADH).
2. The metabolism of a significant amount of ethanol increases the NADH/NAD+ ratio
3. This then promotes the conversion of pyruvate to lactate, diverting pyruvate away from the gluconeogenesis pathway

Question 11

In isolated ethanol intoxication, what is the significance of the presence of horizontal gaze nystagmus?

Answer 11

has a sensitivity of 80-90% for blood ethanol levels of 100 mg/dL

Question 12

Most common cause of an osmolar gap on serum electrolyte analysis

Answer 12

ethanol ingestion

Question 13

remarks on ethanol and metabolic acidosis

Answer 13

Ethanol ingestion may be associated with a mild metablic acidosis, but a significant anion gap metabolic acidosis suggests the presece of
- lactic acidosis,
- ketoacidsois,
- methanol or ethylene glycol toxcitiy

Question 14

General management of ethanol intoxication

Answer 14

1. Observation until sobriety.
2. IV dextrose 0.5 to 1 g/kg for hypoglycemia

**Fluid administration does not hasten alcohol elimination, so establishment of IV access for fluid administration alone is unnecessary in uncomplicated mild to moderate intoxication*

The prevalence of vitamin deficiencies in *acutely intoxicated ED patients is low and does not justify the routine use of IV vitamin-containing fluids

Question 15

Wernicke’s encephalopathy

Answer 15

TRIAD
Altered mental status
Nystagmus
Ataxia

Requires daily treatment with thiamine 100 mg, until normal diet is resumed.

Question 16

Drug that enhances the metabolism of ethanol and accelerates recovery?

Answer 16

Metadoxine
900 mg IV is reported to double the rate at which ethanol blood levels decrease

Question 17

Disposition in ethanol intoxication

Answer 17

Patients with acute ethanol intoxication as the only clinical problem requires ED observation until sober

Clinical judgment, rather than a serum ethanol level, determines the appropriateness of discharge

Patients treated for alcohol intoxication should not be responsible for their own transportation alone