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-
- first stage- CNS effects ( first 12 hours),
- second stage- cardiopulmonary effects ( HTN, CCF, ARDS etc) metabolic acidosis with high anion gap and high osmolar gap and
- 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
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.
- tremors, tachycardia, and anxiety;
- Seizures may occur 6-12 hrs after the last drink
- manifests 48-72 hrs after the last drink but can last up to 10 days
- Mental confusion
- autonomic hyperactivity
- visual hallucinations
- severe agitation
- 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
- Confusion, ataxia, and ophthalmoplegia (nystagmus)
- Amnesia and confabulations