Discrepancies between diagnoses of methanol and ethylene glycol intoxication based on determinations performed in the regional clinical toxicology centre and in the department of forensic medicine

Abstract

The situations in which autopsy blood toxicology results do not confirm methanol and/or ethylene glycol intoxications diagnosed during patients` hospitalizations are frequently observed in the Department of Forensic Medicine in Lublin. Material and methods: In order to verify inconsistent findings, serum samples of 18 individuals, routinely stored in the regional clinical toxicology centre after testing, were re-examined using the specific method of gas chromatography (GC). Results: None of the fatal methanol intoxications was confirmed; toxic concentration of glycol was detected only in one case whereas the remaining determinations were negative or revealed “congeneric” concentrations. In cases of negative results of chromatographic re-analyses, the difference between hospital analysis and GC results were on average 29.6 mg% (max. 127.7 mg%) for glycol and 31.8 mg% (max. 80.0 mg%) for methanol. Severe metabolic acidosis was found in all hospitalized patients. In the hospital setting, “intoxications” were diagnosed even when low concentrations of methanol or glycol (below the cut-off values) were detected with spectrophotometry, which is the method still used in the hospital laboratory. The diagnosis of methanol intoxication in a car accident victim was particularly bizarre; as were the methanol intoxication diagnoses established in cases of acute diabetes-associated complications (4), pancreatitis (1), pneumonia (2) and peritonitis (1), gastrointestinal haemorrhage (1), and decompensated hepatic cirrhosis (1). The therapeutic management based on those diagnoses was incorrectly targeted at the non-existing intoxication that was considered the cause of patient’s deteriorating condition. Conclusions : Our findings indicate inadequate knowledge of physicians to interpret and critically verify toxicological results. Moreover, low cost and speed of spectrophotometric analysis should not veil its significant limitations: mainly low specificity and interference with exo- and endogenous blood constituents, especially in cases of concomitant metabolic disorders