Risk factors related to poor outcome after methanol poisoning and the relation between outcome and antidotes – a multicenter study

Abstract

Introduction. Thorough prognostic and metabolic studies of methanol poisonings are scarce. Our aims were to evaluate the factors associated with sequelae and death from methanol poisoning, to develop a simple risk-assessment chart to evaluate factors associated with sequelae and death from methanol poisoning, and to compare the antidotes ethanol and fomepizole. Patients and methods. We present a retrospective observational case series of methanol-poisoned patients from Norway (1979 and 2002–2005), Estonia (2001) and Tunisia (2003/2004), and patients from two different centers in Iran (Teheran 2004–2009 and Mashhad 2009–2010) who were identified by a positive serum methanol and had a blood acid-base status drawn on admission. The patients were divided into different groups according to their outcome: Survived, survived with sequelae, and died. Results. A total of 320 patients were identified and 117 were excluded. Of the remaining 203 patients, 48 died, and 34 were discharged with neurological sequelae. A pH < 7.00 was found to be the strongest risk factor for poor outcome, along with coma (Glasgow Coma Scale (GCS) < 8) and a pCO₂ ≥ 3.1 kPa in spite of a pH < 7.00. More patients died despite hyperventilation (low pCO₂) in the ethanol group. Conclusions. Low pH (pH < 7.00), coma (GCS < 8), and inadequate hyperventilation (pCO₂ ≥ 3.1 kPa in spite of a pH < 7.00) on admission were the strongest predictors of poor outcome after methanol poisoning. A simple flow-chart may help identify the patients associated with a poor outcome.

Keywords:

• Methanol poisoning
• Prognosis
• Antidote
• Metabolic disturbances