Poisoning with Alcohol and Related Substances

Poisoning with Alcohol and Related Substances

Methanol and Ethylene glycol poisoning

1) Methanol can cause retina injury leading to blindness ( eye manifestations can happen as early as 15-20 hours post ingestion) ?  secondary to the accumulation of formic acid/ formaldehyde;

That’s why the first thing you do in suspected methanol poisoning is …

to check retinal inflammation

Methanol can be found in wood solvent, sterno, paint thinner, photocopier fluid, and cleaning solutions such as windshield washer solution

2) Ethylene glycol (coolant, anti-freeze) poisoning
toxic metabolite is Oxalic acid/ oxalate >> damage kidneys
usually has 3 distinct clinical phases-

  1. first stage- CNS effects ( first 12 hours),
  2. second stage- cardiopulmonary effects ( HTN, CCF, ARDS etc) metabolic acidosis with high anion gap and high osmolar gap and
  3. third stage- renal effects- ARF.

Tip to memorize: You see? going from top to bottom in order –  CNS -> CVS -> Renal

Initial Dx – check hypocalcemia, envelope-shaped oxalate crystals in urine

Mx

Acute management include gastric lavage and correct the metabolic acidosis.
fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol, however it cannot remove toxic substance formed already.


Haemodialysis can be done for effective and faster removal of the toxic metabolites.

Folinic acid can be used to protect against ocular toxicity of methanol whereas thiamine are administered to drive metabolism of ethlylene glycol to non-toxic metabolism.

Isopropyl alcohol ingestion and toxicity may be known only by the history, presentation with normal anion gap acidosis and specific drug level.

Alcohol

Mild withdrawal:
  • tremors, tachycardia, and anxiety;
  • Seizures may occur 6-12 hrs after the last drink
Delirium tremens (DT):
  • manifests 48-72 hrs after the last drink but can last up to 10 days
  • Mental confusion
  • autonomic hyperactivity
  • visual hallucinations
  • severe agitation
  • diaphoresis
Alcoholic hallucinosis:
  • may be confused with DT
  • starts 12-24 hours after last drink but can last days to weeks
  • Paranoid psychosis without tremors and confusion
  • Normal vital signs (no HTN and tachycardia)
  • No agitation
  • Normal appearance except for auditory (most common), visual, or tactile hallucinations
Wernicke encephalopathy:
  • Confusion, ataxia, and ophthalmoplegia (nystagmus)
Korsakoff psychosis:
  • Amnesia and confabulations
*alcohol withdrawal has a very high mortality rate (5%)
Tx
Benzodiazepines
avoid antipsychotics/neuroleptics such as haloperidol (due to risk of lower seizure threshould and prolonged QT interval)