Daily Pearl 11/11

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    Daily Pearl 11/11

    A 58 y/o M presents to the ED with altered mental status. He smells of alcohol, appears drunk, and has a longstanding history of alcohol abuse. You obtain a serum alcohol level of 100. Further laboratory work up shows a pH 7.28 with CO2 53, HCO3 25, lactate 3.5.   After an hour, he has 2 episodes of hematemesis.

    What important group of diagnoses must you consider in the patient’s work up? How can you differentiate among them?

     

    This patient has a toxic alcohol ingestion. He drank isopropanol after running out of vodka at home. Additional laboratory work up shows a serum osm of 380, with overall osmol gap of >30. He has a non-anion gap acidosis without compensation. Furthermore, he is found to be anemic with guaiac (+) stool and evidence of GI bleed, consistent with a known complication of isopropyl alcohol ingestion – hemorrhagic gastritis.

    See below for key points to remember about the three most common toxic alcohols:

    Methanol
    -Found in windshield washer fluid, solid cooking fuel, perfumes, dry gas.
    -Metabolic acidosis with elevated anion gap
    -Formic acid and lactic acid are responsible for subsequent acidosis
    -Causes visual impairment, classically snowfield vision or total blindness. Central scotoma and hyperemia of optic disc with papilledema, with possible afferent papillary defect are seen on exam.
    -Rare reports of renal failure and pancreatitis after methanol poisoning.

    Ethylene glycol
    -Used as engine coolant antifreeze.
    -Metabolic acidosis with elevated anion gap
    -Highly inebriating compared to others due to higher molecular weight
    -Glycolic acid responsible for acidosis
    -Leads to nephrotoxicity
    -Can cause hypocalcemia, leading to QT prolongation and dysrhythmias.
    -Calcium oxalate crystals seen in urine

    Isopropanol
    -Used primarily as rubbing alcohol (household preparations are 70%).
    -The most common toxic alcohol exposure reported to poison centers
    -Metabolized to acetone
    -Ketosisis without acidosis
    -Hemorrhagic gastritis has been reported in association with isopropyl alcohol intoxication.

    Management

    Serum concentrations of toxic alcohols are send out studies, and usually not helpful in the acute setting. Instead, use the osmol gap. Although not sensitive or specific, a markedly elevated osmol gap (>50) is difficult to explain by anything other than a toxic alcohol.

    Fomepizole is used as competitive antagonist of ADH. Dose 15 mg/kg IV loading dose, followed by 10mg/kg q12 h. Any patient with a believable history of methanol or ethylene glycol ingestion should be treated until serum concentrations of the toxic alcohol are available.

    Hemodialysis indications:  Severe metabolic acidosis, signs of end-organ toxicity including coma and seizures and renal failure

    Credit to Dr. Joseph Scofi for inspiring this pearl.

    Wiener SW. Chapter 107. Toxic Alcohols. In: Nelson LS, etal. Goldfrank’s Toxicologic Emergencies. 9th ed. New York: McGraw-Hill; 2011. http://www.accessemergencymedicine.com/content.aspx?aID=6527628.

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