From the Guidelines
Paraquat poisoning is a medical emergency that requires immediate treatment, and oxygen therapy should be restricted to only when the saturation falls below 85% and reduced or stopped when the saturation rises above 88% to minimize further lung damage. The effects of paraquat poisoning can be severe and have a high mortality rate, causing organ damage, particularly in the lungs, liver, and kidneys [ 1 ]. Treatment involves preventing further absorption through gastric lavage with activated charcoal (50-100g) if the patient presents within 1-2 hours of ingestion.
Key Treatment Considerations
- Fuller's earth (1-2g/kg in 200-500ml water) or activated charcoal can be given orally to adsorb paraquat in the gut.
- Supportive care includes maintaining fluid and electrolyte balance, managing respiratory distress, and treating specific organ failures.
- Hemodialysis or hemoperfusion may be attempted early but has limited effectiveness as paraquat rapidly distributes to tissues.
- Immunosuppressive therapy with cyclophosphamide and methylprednisolone may be used to reduce lung inflammation.
- N-acetylcysteine may help as an antioxidant to reduce oxidative stress caused by paraquat. Paraquat causes damage through oxidative stress, generating reactive oxygen species that destroy cell membranes and tissues. Prevention through proper handling and storage of this herbicide is crucial as there is no specific antidote [ 1 ].
From the Research
Effects of Paraquat Poisoning
- Paraquat poisoning can cause severe illness and death, usually occurring within 2 days of ingestion of 50 mg/kg or more 2
- The toxic compound accumulates in lung tissue, leading to diffuse alveolitis and extensive pulmonary fibrosis 2
- Renal failure may develop in patients who eventually die, but it may not indicate a fatal outcome if present alone 2
- Ingestion of toxic doses of paraquat can be fatal with life-threatening effects on the lungs, gastrointestinal tract, kidney, liver, heart, and other organs 3
- Long-term survivors of paraquat poisoning may experience gastrointestinal and pulmonary complications 3
Organ-Specific Effects
- Lung: paraquat poisoning can cause pneumonitis and lung fibrosis due to the accumulation of the toxic compound in lung tissue 2, 4
- Kidney: paraquat poisoning can cause renal failure and acute kidney injury 2, 4, 5
- Liver: paraquat poisoning can cause liver injury 5
- Heart: paraquat poisoning can cause cardiovascular collapse in severe cases 6
- Gastrointestinal tract: paraquat poisoning can cause mucosal irritation and gastrointestinal complications 3, 6
Prognosis and Treatment
- The prognosis of paraquat poisoning is determined by the time of poisoning and the plasma paraquat concentration before treatment 4
- Proudfoot's curve provides a simple method of predicting the survival rate 4
- Treatment of paraquat poisoning remains ineffective, but measures such as activated charcoal, Fuller's earth, and resins may prevent some absorption of the toxin 2, 5
- Extracorporeal therapy, such as haemodialysis and haemoperfusion, may be attempted, but its effectiveness is unclear 2, 4, 5
- Antioxidants, such as acetylcysteine and salicylate, may be beneficial through free radical scavenging, anti-inflammatory, and NF-κB inhibitory actions, but there are no published human trials 5