9. Alcohol Toxicity

Question 1

where is alcohol rapidly absorbed

Answer 1

GI

Question 2

true or false: ethanol is water soluble

Answer 2

true

Question 3

when do the concentrations of alcohol peak

Answer 3

20-60 mins

Question 4

which enzymes predominantly metabolize EtOH

Answer 4

cytosolic alcohol dehydrogenase and aldehyde dehydrogenase

Question 5

what is a minor metabolic pathway that can be induced in the metabolism of EtOH

Answer 5

microsomal ethanol oxidizing system (MEOS) P450 enzyme system

Question 6

what effects are typically seen if your BAC is >0.15

Answer 6

severe impairment, n/v, blackout, unconsciousness, resp. depression, life threatening

Question 7

the enzymatic conversion of alcohol also involves the conversion of

Answer 7

NAD to NADH

Question 8

what will happen if the body needs NAD?

Answer 8

NADH will be converted back to NAD by using pyruvate. this results in the depletion of pyruvate and the production of lactate

Question 9

an increase in lactate which is often seen in excessive EtOH consumption may cause:

Answer 9

metabolic acidosis

Question 10

body uses pyruvate to produce glucose when intake is low via:

Answer 10

gluconeogenesis

Question 11

what are the three ways ethanol causes hypoglycemia

Answer 11

1. decreased intake of glucose
2. blockade of gluconeogenesis
3. inhibition of glycogenolysis

Question 12

patients with acute intoxication may exhibit _____________ in which dysrhythmias, especially a-fib, occur after a heavy drinking episode

Answer 12

holiday heart

Question 13

what lab values should be measured in someone with suspected alcohol toxicity

Answer 13

• serum ethanol concentrations
• liver and kidney function
• electrolyte levels (anion gap - presence of a large anion gap should suggest the ingestion of an alcohol substitute)
• serum glocsue (most imp. test) *make sure they are not in severe hypoglycemia)

Question 14

how should serum glucose be monitored in patients with uncomplicated alcohol toxicity vs. severe toxicity

Answer 14

uncomplicated toxicity = no LOC
- monitor BG q8h

severe toxicity = LOC/seizures
- monitor BG q1h

Question 15

what is the treatment for ethanol toxicity

Answer 15

wait & watch
- fluids in patients with volume depletion
- thiamine and glucose for those who present unconscious

Question 16

true or false: activated charcoal and gastric lavage are used in all patients that present with alcohol toxicity

Answer 16

false - need to be used within 1 hr of ingestion of alcohol therefore in most scenarios activated charcoal and gastric lavage are not helpful

Question 17

which of the following are toxic
A) methanol
B) ethylene glycol
C) their metabolites
D) all of the above

Answer 17

C

Question 18

what is the rate limiting step of the metabolism of methanol

Answer 18

methanol converted to formaldehyde

Question 19

this is the metabolite of methanol. it can eventually cause permanent blindness. the metabolism of this metabolite is very slow therefore it often accumulates in the body which can result in metabolic acidosis

Answer 19

formic acid

Question 20

where do ethylene glycol metabolites target?

Answer 20

kidney - can lead to AKI

Question 21

oxalic acid can bind to serum calcium to produce ________ which can deposit in the kidneys, brain and lung tissue

Answer 21

calcium oxalate crystals

Question 22

when do the initial symptoms appear from methanol and what do the symptoms typically look like?

Answer 22

12-24 hours after ingestion

often resembles ethanol intoxication and consist of drowsiness, confusion, ataxia, weakness, headache, n/v and abdominal pain

Question 23

as methanol metabolism proceeds, a severe anion gap metabolic acidosis will develop due to formation of formic production. what symptoms may be seen here?

Answer 23

blurred or misty vision, double vision, changes in colour perception. occasionally total loss of vision.

Question 24

what are the 3 phases of ethylene glycol poisoning

Answer 24

phase 1 (mins-12 hrs) : CNS toxicity + GI symptoms

phase 2 (12-24 hrs): cardiopulmonary symptoms

phase 3 (> 24 hrs): tubular necrosis and renal failure

Question 25

if a patient presents with alcohol toxicity but it is not evident which type of alcohol they may be intoxicated with, what lab values will reveal the type of alcohol?

Answer 25

anion gap
- large anion gap suggest alcohol sub

serum ethanol level
- normal suggests alcohol sub

Question 26

what supportive care is done to manage methanol or ethylene glycol toxicity

Answer 26

• securing patients ABCs
• GI decontamination if possible
• IV sodium bicarb to correct systemic acidosis

Question 27

what are antidotal therapies seen in the management of methanol or ethylene glycol toxicity

Answer 27

fomepizole (1st line) - blocks alcohol dehydrogenase

ethanol - alcohol dehydrogenase prefers ethanol therefore will stop making methanol or ethylene glycol metabolites

Question 28

what are some cofactor therapies seen in methanol and ethylene glycol toxicity

Answer 28

eliminiation of formate (toxic metabolite of methanol) is sped up by administration of folic acid; thus all patients treated with an ADH blocker should also receive folinic acid (either leucovorin or folic acid IV)

ethylene glycol patients are treated with pyridoxine and thiamine (cofactors of metabolism therefore they speed up metabolism)