PROGNOSTIC FACTORS IN PATIENTS WITH METHANOL POISONING

Objective: To identify prognostic factors in methanol poisoning and de termine the effect of medical interventions on clinical outcome. Metho ds: Retrospective review of all patients treated for methanol poisonin g from 1982 through 1992 at The Toronto Hospital. Presenting history, physical examination, results of laboratory tests, medical interventio ns, and final outcomes after hemodialysis were abstracted. Results: Of 50 patients treated for methanol poisoning, 18 (36%) died, 32 (64%) s urvived. Seven of the 32 survivors sustained visual sequelae (22%), th e remaining 25 (78%) recovered completely. Patients presenting with co ma or seizure had 84% (16/19) mortality compared to 6% (2/31) in those without (p < 0.001). Initial arterial pH < 7 was also associated with significantly higher mortality (17/19, 89% vs 1/31, 3%, p < 0.001). T here were no differences in time from presentation to dialysis between survivors and fatalities (8.4 +/- 3.6 vs 7.6 +/- 3.5 hours, p = 0.47) . The deceased patients had higher mean methanol concentration than th e survivors (83 +/- 53 vs 41 +/- 25 mmol/L, p = 0.004). Subgroup analy sis of 19 patients presenting with visual symptoms who survived showed prolonged acidosis (5.4 +/- 2.3 vs 3.0 +/- 2.1 hours, p = 0.06) in th ose with persistent visual sequelae. Conclusions: Coma or seizure on p resentation and severe metabolic acidosis, in particular initial arter ial pH < 7, are poor prognostic indicators in methanol poisoning. Surv ivors presented with lower methanol concentrations. Patients with resi dual visual sequelae had more prolonged acidosis than those with compl ete recovery. Future studies will be needed to confirm the effect of c orrection of acidosis on final clinical outcome.