Ver el código de «Methanol toxicity»

== Background ==
*Found in antifreeze, windshield washer fluid
*Parent compound causes only mild inebriation; metabolite (formic acid) causes toxicity
**Binds to cytochrome oxidase > blockade of oxidative phosphorylation > lactic acidosis

==Clinical Features==
#Symptoms begin 12-24hr after ingestion (may occur even later if ETOH is co-ingested)
##CNS depression
###Confusion, ataxia, depressed mental status, seizure 
###Less inebriating than ethanol or ethylene glycol
##Visual disturbances (50% of pts)
###Development may precede or parallel that of other clinical symptoms
###Cloudy or blurry vision ("stepping out into a snowstorm")
##Anion-gap acidosis
###May be severe (bicarb < 5, pH < 7)
###Compensatory tachypnea

== Work-Up ==
*Chemistry
**Anion gap acidosis
*Serum Osm
**Osm gap (measured - calculated)
***Calculated serum osm = 2Na + BUN/2.8 + glucose/18 + ethanol/4.6
***Normal is < 10
***Note: Cannot rule out toxic ingestion with a "normal" osmol gap
****Only parent alcohol is osmotically active
****Delayed presentation may mean that much of it is already metabolized
*Ethanol level
*VBG

== Treatment ==
#Correction of metabolic acidosis with bicarbonate
##Bicarbonate 1-2mEq/kg IV bolus to attain pH = 7.45-7.50
###Follow by infusion of 150mEq/L in D5 @ 1.5-2x maintenance fluid rate
###Monitor for worsening hypocalcemia
#ADH enzyme blockade
##Fomepizole (4-MP)
###15mg/kg followed by 10mg/kg q12hr x 4 doses
##Ethanol
###BAL of 100-150 completely saturates alcohol dehydrogenase
#Removal of parent alcohol and metabolite via dialysis
##Indications (controversial):
###Severe acidosis (pH <7.30)
###Visual symptoms
###Electrolyte imbalances unreponsive to conventional therapy
###Anion gap > 20
#Other
##Folinic acid 50mg IV q4hr
###Enhances formic acid metabolism

== Source ==
*Rosen's
*Tintinalli

[[Category:Tox]]