Veiled Paraquat Poisoning - A Focus on Clinical Characteristics

Abstract

Purpose: Most paraquat poisonings are easily diagnosed by history taking on physical examination, however, some are failed to be diagnosed initially if the poisoning was veiled. The purpose of this study was to explore the clinical characteristics of veiled paraquat poisoning.

Methods: We retrospectively reviewed the medical records of patients whose discharge diagnosis was paraquat poisoning in one university teaching hospital between 1 Jan, 2001 and 31 Dec, 2010. Veiled paraquat poisoning was determined when there was a positive urine paraquat kit in patients who did not mention paraquat poisoning in an initial physical examination or had unknown cause of pulmonary fibrosis, acute renal failure, or multi-organ failure.

Results: Of the 117 patients with paraquat poisoning during the study period, 6 patients (5.1%) had veiled paraquat poisoning. The clinical characteristics were 1) proteinuria - 6 (100%), 2) increased creatinine - 4 (66.7%), 3) green skin stains - 2 (33.3%), 4) mucosal ulcer - 3 (50%). Blood chemistry results were variable.

Conclusion: We should suspect veiled paraquat poisoning for patients who have proteinuria, increased creatinine, green skin stain, mucosal ulcer and vomiting, or if they have rapidly progressing acute renal failure or multi-organ failure with unknown cause, even if patients didn’t mention about paraquat poisoning upon the initial physical examination.

In cases with the above clinical conditions, a thorough repeated physical examination including history taking and use of urine paraquat kits should be performed.