Aspectos gerais e diagnóstico clinicolaboratorial da intoxicação por paraquat

INTRODUCTION: Paraquat is a herbicide widely used in agriculture. It is a very toxic product, fatally poisoning mainly by the lack of an efficient antidote to revert the clinical state. FISIOPATHOLOGY: Toxicological effects are decurrent of oxidative stress. The most important target organ is the lung, which can display edema, hemorrhage, interstitial inflammation and fibroses, culminating in serious respiratory failure and death. Moreover, it is nephrotoxic, hepatotoxic, miotoxic and neurotoxic. TREATMENT: Besides aiming the decrease of absorption and stimulating the excretion of absorbed paraquat, the poisoning treatment nowadays is based on measures that decrease oxidative stress using antioxidants, consequently reverting clinical state, mainly the pulmonary. Diagnostic methods: Among the available quantitative methods, the chromatographic are the most reported ones for biological samples. However, capillary electrophoresis and immunoassay methods can be used. Immunoassays stand out for being typically found in hospital laboratories, while chromatographic and electrophoretic methods are not. On the other hand, a simple and fast urinary reaction with sodium dithionite is very utilized because it is predictive in acute poisoning suspect. CONCLUSION: In the presence of high morbimortality potential in paraquat intoxications, the reversion of pulmonary toxicity with antioxidants is extensively studied, but a specific antidote is not established. In laboratorial diagnostic, chromatographic, electrophoretic and immunologic techniques are applied to paraquat quantification, although in clinical toxicology the sodium dithionite reaction is still significant.