Fatality after inhalation of methanol-containing paint stripper

To the Editor:

Methanol is found in a variety of commercially available products. Regardless of the route of administration, the parent compound causes inebriation, while subsequent toxicity is related to its metabolism to formic acid. We present a case of central nervous system depression and profound metabolic acidosis following intentional inhalation of a paint-stripping product containing methanol, methylene chloride, and toluene.

A 62-year-old male was brought to the emergency department by his son for increased agitation. The patient admitted to inhalant abuse earlier that day, and his son brought the container of Strypeeze Original (methanol: 25–30%, methylene chloride: 25–30%, toluene: 15–20%, and acetone: 15–20%). The patient was normothermic, with blood pressure of 120/95 mmHg, heart rate of 96 beats per minute, respiratory rate of 18, and an oxygen saturation of 98%. His son confirmed that his father had a long history of inhalant abuse of such products. Aside from agitation, the physical examination was unremarkable. The emergency department staff later found him unresponsive, at which point he was promptly intubated. Initial laboratory testing demonstrated pH, 6.61; bicarbonate, < 10 mmol/L; anion gap, 21 mEq/L; creatinine, 2.2 mg/dL; methanol, 72 mg/dL; undetectable ethylene glycol; and carboxyhemoglobin, 2.9%. The patient was given sodium bicarbonate and fomepizole, and underwent two 4-hour hemodialysis sessions over the first 36 h of hospitalization. Despite normalization of laboratory values, the patient remained comatose. Computed tomography of the head on day 4 revealed cerebral edema with ischemic changes involving more than 50% of the brain, but did not reveal any putamen lesions. Electro-encephalography showed global encephalopathy. The patient was extubated on day 9 and was discharged to hospice care where, his family reported, he expired within 24 h, although the exact way in which he died is unclear.

Methanol is a volatile substance with a vapor pressure of 125 mmHg at 25°C. The vast majority of cases reported to U.S. poison centers—and the greatest body of clinical experience—is with ingestion, but systemic absorption may also occur via dermal exposure or inhalation. Controversy exists over the actual risk of significant toxicity occurring from these latter routes of administration, as several case reports and series purport no serious sequelae,^1,2 while others have documented vision loss³ and even one death,⁴ although co-ingestants were present. In none of the cases we reviewed was the acidosis as profound as that seen in our patient, and rarely were the clinical sequelae associated with an inhalation exposure as severe as demonstrated by our case.

Interestingly, the patient's carboxyhemoglobin concentration was normal, likely due to the relatively low concentration of methylene chloride. Additionally, carbon monoxide generation from methylene chloride is not predictable and up to 70% of methylene chloride is metabolized to carbon dioxide instead.⁵

This case was referred to our regional poison center and is limited by a detailed assessment that would otherwise be obtained by bedside consultation. The possibility that the patient ingested the product seems unlikely given that the family reported a known history of inhalant abuse and there were no signs of caustic injury that would be expected with such ingestion.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.