Paraquat toxicity

Background

Paraquat is an herbicide that has a rapid and large distribution and can be fatal even with small ingestions. It has a high case-fatality rate (>50%) which makes it a frequent means of suicide in the developing world, as well as a dangerous accidental occupational exposure.

Paraquat exerts its toxic effects via multiple proposed mechanisms, including lipid peroxidation and generation of reactive oxygen species, direct mitochondrial toxicity, and apoptosis.

Clinical Features

Paraquat Tongue (Credit: wikitox.org)

Overall, pulmonary and renal toxicities predominate and are the primary cause of mortality. GI toxicity is usually limited.

• Gastrointestinal: predominate early
  • Paraquat tongue
  • Esophageal and gastric erosion
  • Nausea and vomiting
• Pulmonary: occurs due to distribution to pneumocytes
  • Pneumonitis
  • Pulmonary fibrosis (delayed)
• Multiorgan failure
  • Acute renal failure
  • Hepatic necrosis
  • Myocardial necrosis
  • Internal bleeding