Paediatric paraquat poisoning – two case reports from a quaternary care centre

Abstract

Paraquat (PQ), or N, N′-dimethyl-4,4′-bipyridinium dichloride, is a widely used herbicide. It is highly toxic and enters the human body mainly by swallowing or through damaged skin but may also be inhaled. Due to its properties being corrosive, it can easily damage the skin, thereby making it easy to absorb. Paraquat poisoning has no known cure and is still a serious toxicological emergency with significant death rates. When paraquat enters into the body, it causes redox cycling and generation of reactive oxygen species (ROS). Once inside the cells, paraquat accepts an electron from nicotinamide adenine dinucleotide phosphate (NADPH) forming the paraquat radical which later becomes a superoxide radical by donating its electron to molecular oxygen. During this process, paraquat is regenerated, thereby continuing the vicious cycle. The mechanism of death is usually respiratory failure and may occur within a few days after poisoning or as long as a month later. The mainstay in the management of paraquat poisoning is supportive care with primary importance given to preventing absorption and promoting the excretion of the toxic compounds all whilst mitigating organ damage. This case series of a 14-year-old and a 17-year-old with paraquat ingestion examines the classic clinical presentation, management challenges and high mortality of paraquat toxicity.