What is the treatment for Paraquat poisoning?

Treatment of Paraquat Poisoning

Paraquat poisoning requires immediate aggressive decontamination with activated charcoal or Fuller's earth, strict oxygen restriction (target SpO2 85-88%), and early consideration of hemoperfusion, with outcomes heavily dependent on the ingested dose and speed of intervention. 1, 2

Immediate Rescuer and Healthcare Worker Safety

• Wear protective clothing and gloves before any patient contact to prevent direct skin exposure and inhalation of toxic fumes from contaminated clothing or body fluids. 2, 3
• Remove all contaminated clothing and jewelry immediately to prevent continued exposure. 3
• Contact a poison control center immediately for expert guidance and maintain continuous contact for evolving recommendations. 2, 3

Critical Oxygen Management - Unique to Paraquat

Paraquat toxicity is uniquely worsened by oxygen through increased free radical production. 1, 2

• Administer supplemental oxygen ONLY if SpO2 falls below 85%. 1, 2, 3
• Target oxygen saturation of 85-88%, which is dramatically lower than standard critical care targets. 1, 2, 3
• Reduce or stop oxygen therapy if saturation rises above 88%. 1, 2, 3
• This restrictive oxygen strategy is based on the mechanism that oxygen accelerates paraquat-induced lung injury through free radical generation. 1, 2

Common Pitfall: Do not provide supplemental oxygen liberally as you would in other poisonings or critical illnesses—this is uniquely harmful in paraquat toxicity. 1

Decontamination Strategy

Dermal Decontamination (First Priority)

• Immediately remove all contaminated clothing and thoroughly wash all exposed skin areas with soap and water to prevent continued dermal absorption. 1, 2
• In pediatric patients, use warmed shower water at lower pressure with heat lamps and blankets to prevent hypothermia. 1

Gastrointestinal Decontamination

• Multiple-dose activated charcoal (15-20g every 6 hours) is the preferred decontamination method over gastric lavage. 1, 2
• Administer activated charcoal or Fuller's earth as these work through adsorption of the toxin. 1
• Only administer after securing the airway and achieving hemodynamic stability—never delay airway protection to perform decontamination. 1, 2
• The American College of Medical Toxicology recommends against routine gastric lavage for paraquat poisoning. 1

Common Pitfall: Do not use gastric lavage routinely when activated charcoal is the evidence-based alternative. 1

Extracorporeal Treatment

• Hemoperfusion with coated activated charcoal should be performed as "continuous hemoperfusion" approximately 8 hours per day over 2-3 weeks for patients who have ingested significant amounts. 4
• This represents the best measure to eliminate paraquat from blood and tissue. 4
• Consider early initiation in moderate to severe poisoning (ingestion of 20-40 mg/kg or greater). 5, 6

Dose-Based Prognosis and Management Intensity

Mild Poisoning (<20 mg/kg)

• Patients are either asymptomatic or have gastrointestinal symptoms only. 5
• All patients in this category recover fully. 5

Moderate to Severe Poisoning (20-40 mg/kg)

• Expect renal failure (which may recover spontaneously) and pulmonary fibrosis developing over days to weeks. 5
• Death occurs in the majority of cases, usually delayed for 2-3 weeks. 5
• Aggressively manage with intestinal decontaminants and hemoperfusion. 6
• Consider immunosuppressive therapy with steroids and cyclophosphamide. 6

Acute Fulminant Poisoning (>40 mg/kg)

• Multiple organ failure (cardiac, respiratory, hepatic, renal, adrenal, pancreatic, neurological) occurs. 5
• Death may occur within hours and is never delayed more than a few days. 5
• Prognosis is extremely poor despite optimal management. 7

Supportive Care

• Provide standard airway management if respiratory distress develops. 3
• Treat hypotension and dysrhythmias according to standard protocols. 3
• Administer benzodiazepines for seizures or severe agitation if they occur. 3
• Perform intermittent assessment of pulmonary function and plasma/urinary paraquat concentrations. 6

Key Clinical Pitfalls to Avoid

1. Do not delay airway protection to perform gastrointestinal decontamination due to significant aspiration risk. 1
2. Do not provide liberal supplemental oxygen—this accelerates lung injury through free radical production. 1, 2
3. Do not rely on gastric lavage when activated charcoal is superior and evidence-based. 1
4. Most cases now involve deliberate self-poisoning with suicidal intent rather than accidental ingestion, which influences the typical doses encountered. 5, 8