TOXICOLOGY QUESTION OF THE WEEK
October 20, 2023
How do you diagnose toxic alcohols without alcohol concentrations?
Another case overview from the Fellow’s National Toxicology Case Conference.
A 64-year-old male arrives with 8 stab wounds to the upper abdomen and lower chest (not a tox case at first glance).
VS: BP 86/40; HR 109; minimal respirations; 900 F
Available labs: pH 6.5 HCO3 5 PCO2 23mmol/L CL 117 mmol/L glu 124mg/dL Hct 39%
Went immediately to the OR and received massive transfusions secondary to a 600 mL blood loss. Liver fulguration was performed. PEA arrest occurred; CPR; ROSC; Left OR on 3 pressors
pH 6.9; pCO2 37; pO2 399 initial lactate not reported.
Differential Dx: due to the marked acidosis and acidemia, toxic alcohols were considered, sepsis, metformin
Lactate 21; transaminases slightly elevated. Osmolar gap of 32
Toxic alcohols and lactate gap are sendouts so results will not be available for several days.
Urine-no calcium oxalate crystals and no fluorescence under woods lamp (indicative of fluorescein which is in some ethylene glycol products).
Toxicology recommended the administration of 15 mg/kg fomepizole IV. Nephrology was consulted regarding dialysis but they did not want to dialyze. There was no history of ingestion and not a large enough osmolal gap. Nephrology recommended bicarb drip for few hours and maintain blood volume.
Fomepizole was continued, but dialysis was not performed. Lactate remained elevated with a hyperchloremic acidosis. Creatinine jumped to 5.9. On POD 5 ethylene glycol concentration from hospital day 1 returned at 62 mg/dL. At that time, the patient was extubated and doing well. On POD 6 dialysis was performed due to poor renal function. On day 27 Cr 1.7.
Question submitted by Donna Seger MD
Comment: Although this is a brief overview, there are several clinical discussion points. A very low bicarb means one should consider ingestion and metabolism of toxic alcohols-even without a history of ingestion. The combination of an osmolal and anion gap is even more supportive of a toxic alcohol ingestion. Clearly, there were additional causes for the acidosis. Most hospitals do not have the luxury of on-site laboratory technology to directly measure ethylene glycol or methanol concentrations, so the osmolal gap tells you how many osmols are in the blood. OSM=2Na+glucose/18+BUN/2.8 (calculated). Difference between the measured and calculated osmols is the osmolal gap. Normal gap may vary from -14 to +10 so the result may not be sensitive or specific. The absence of a significant osmolal gap does not exclude a toxic alcohol ingestion. Only the parent compounds contribute to the serum osmolality. Fomepizole stops the metabolism of the parent compounds, ethylene glycol/methanol. If the toxic alcohol is elevated, dialysis may be needed in addition to fomepizole. Fomepizole only slows the metabolism so much that it may need to be administered for days. Fomepizole is an expensive drug. Fomepizole is also dialyzable so administration must be frequent during dialysis. Dialysis may be needed as well to remove the toxic metabolites. Note that there were no urinary oxalate crystals or fluorescence. These are not sensitive tests, and clearly their absence did not indicate the absence of ethylene glycol. Great case. The discussion was very animated, as you can imagine. Ds
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DONNA SEGER, MD
Department of Medicine
TENNESSEE POISON CENTER
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