What is the treatment for a patient with paraquat poisoning?

Management of Paraquat Poisoning

Paraquat poisoning requires immediate aggressive decontamination, strict oxygen restriction (target SpO2 85-88%), early poison control consultation, and consideration of hemoperfusion, with the understanding that mortality remains extremely high despite optimal treatment. 1, 2

Immediate Actions

Decontamination and Exposure Control

• Remove all contaminated clothing and jewelry immediately to prevent continued dermal absorption 1, 2
• Thoroughly wash all exposed skin with soap and water using warmed water at lower pressure to prevent hypothermia 2
• Healthcare workers must wear appropriate personal protective equipment (gloves, protective clothing) when handling the patient or contaminated materials 1

Gastrointestinal Decontamination

• Administer multiple-dose activated charcoal (15-20g every 6 hours) or Fuller's earth as the preferred decontamination method, but only after securing the airway and achieving hemodynamic stability 2
• Do not perform routine gastric lavage - activated charcoal is the evidence-based alternative 2
• Sequential gastrointestinal lavage with montmorillonite powder (60g oral), followed by small-volume low-pressure gastric lavage with 2.5% bicarbonate, then activated charcoal, montmorillonite powder, and polyethylene glycol electrolyte solution may reduce mortality and organ damage 3
• Never attempt decontamination without first ensuring airway protection due to significant aspiration risk 2

Expert Consultation

• Contact poison control center immediately for expert guidance and maintain continuous contact for evolving treatment recommendations 1, 2

Critical Oxygen Management (Unique to Paraquat)

This is the most critical pitfall to avoid - paraquat toxicity is dramatically worsened by supplemental oxygen through increased free radical production. 1, 2

• Administer oxygen ONLY if SpO2 falls below 85% 1, 2
• Target oxygen saturation of 85-88% - significantly lower than typical critical care targets 1, 2
• Reduce or stop oxygen if saturation rises above 88% 1, 2
• Oxygen accelerates paraquat-induced lung injury and should not be provided liberally 2

Enhanced Elimination

• Consider early hemoperfusion or hemodialysis for ingestions greater than 20-40 mg/kg of paraquat concentrate 4, 5, 6
• Hemoperfusion should be initiated as early as possible to enhance toxin elimination 4, 6

Supportive Care

Airway and Hemodynamic Management

• Provide standard airway management if respiratory distress develops 1
• Treat hypotension and dysrhythmias according to standard protocols 1
• Administer benzodiazepines for seizures or severe agitation if they occur 1

Antioxidant Therapy

• Consider early administration of antioxidant therapy including deferoxamine (100 mg/kg in 24 hours) and continuous infusion of acetylcysteine (300 mg/kg/day for 3 weeks) to limit systemic toxicity 4
• This approach may be beneficial when combined with measures that prevent digestive absorption or enhance elimination 4

Immunosuppressive Therapy

• Consider administration of immunosuppressive therapy (corticosteroids and cyclophosphamide) to prevent late-onset irreversible pulmonary fibrosis from inflammatory cell recruitment 5, 3
• Large doses of corticosteroids have been used in clinical practice 3

Monitoring

• Intermittent assessment of pulmonary function 5
• Monitor plasma and urinary concentrations of paraquat if available 5
• Serial monitoring of serum potassium, amylase, ALT, total bilirubin, BUN, creatinine, lactate, and PaO2 3
• Watch for development of acute renal failure, hepatic dysfunction, and progressive pulmonary fibrosis 4, 6

Common Pitfalls to Avoid

• Do not delay airway protection to perform gastrointestinal decontamination 2
• Do not provide supplemental oxygen liberally - this is uniquely harmful in paraquat toxicity 2
• Do not use gastric lavage routinely when activated charcoal is the evidence-based alternative 2
• Do not wait to contact poison control - immediate consultation is essential 1, 2

Prognosis

Despite optimal management, mortality remains extremely high (up to 95%) for oral paraquat poisoning, particularly with ingestions exceeding lethal doses 6, 7. Death may occur from gastrointestinal caustic lesions, shock, ARDS, or progressive pulmonary fibrosis with refractory hypoxemia 4, 6. Early aggressive treatment may improve outcomes in some cases, but the overall prognosis remains poor 4, 3.