A Clinical Study of Prognosis and Glucocorticoid Pulse Treatment in Patients with Acute Paraquat Intoxication

Objective: Paraquat is a highly toxic herbicide that binds strongly to tissue and causes high mortality rates due to pesticide intoxication in Taiwan. In this study, we evaluated the usefulness of methylprednisolone pulse therapy and calculation of the severity index of paraquat poisoning (SIPP) to predict the prognosis in patients with oral paraquat intoxication. Materials and Methods: Thirty-two patients with paraquat poisoning from January 2003 to April 2005 were enrolled into this study at a medical center in eastern Taiwan. All 32 patients had history of oral intake of paraquat and urine paraquat was positive at the emergency department. Time of oral intake of paraquat and serum paraquat levels were assayed at the emergency department for calculating SIPP (hour × mg/L) level. Sixteen patients with oral paraquat poisoning were treated with intravenous methylprednisolone 1 g/day and charcoal hemoperfusion for 3 days (MP group), and 16 patients with oral paraquat poisoning were treated with charcoal hemoperfusion only for 3 days (control group). Results: The mortality rate of the patients with oral paraquat poisoning was high (87.5%). There were no statistically significant differences in death (p = 1.000), age (p = 0.706), sex (p = 0.069), serum blood urea nitrogen (p= 0.104), creatinine (p= 0.174), aspartate aminotransferase (p= 0.083), alanine aminotransferase (p = 0.365), plasma level of paraquat (p = 0.880) and SIPP level (p = 0.734) between the MP group and control group. Young age (p = 0.030), lower initial plasma paraquat level (p = 0.002), lower serum creatinine (p = 0.009), female sex (p = 0.033), lower elapsed time from ingestion of paraquat to arrival at hospital (p = 0.035) and SIPP level less than 10 (p < 0.001) were associated with survival in patients with oral paraquat poisoning. Multivariate forward stepwise linear regression analysis of deaths showed that SIPP > 10 (hour × mg/L) (p < 0.001) was an independent predictor of death in patients with oral paraquat poisoning and explained 77.1% of the variance (R² = 0.771). Conclusion: Treatment with methylprednisolone pulse therapy did not show better results in patients with acute oral paraquat poisoning. SIPP was an independent predictor of death in patients with oral paraquat poisoning.