What is the management of paraquat poisoning?

Management of Paraquat Poisoning

The management of paraquat poisoning requires immediate decontamination, early hemoperfusion within 2-4 hours of ingestion, restricted oxygen therapy targeting saturations of 85-88%, and combined immunosuppressive and antioxidant therapy to improve survival. 1

Immediate Management

1. Decontamination

   • Remove contaminated clothing and perform copious irrigation with soap and water
   • Use appropriate personal protective equipment (gloves) to prevent secondary exposure
   • Consider gastric lavage only if within 1-2 hours of ingestion
   • Administer activated charcoal orally as soon as possible 1

2. Hemoperfusion

   • Initiate early hemoperfusion with activated charcoal within 2-4 hours of ingestion
   • Do not delay - efficacy decreases significantly after the first 4 hours post-ingestion 1
   • Consider "continuous hemoperfusion" (approximately 8 hours/day for 2-3 weeks) for severe cases 2

Respiratory Management

• Restrict oxygen therapy - provide oxygen only when saturation falls below 85% to minimize further lung damage
• Target oxygen saturation of 85-88%, as excessive oxygen worsens paraquat-induced lung injury through enhanced free radical production 1
• Avoid mechanical ventilation with high oxygen concentrations when possible
• If intubation is necessary for airway protection, use the lowest possible FiO2 1

Specific Therapeutic Interventions

1. Immunosuppressive Therapy

   • Implement combined immunosuppressive therapy with:
     • Methylprednisolone
     • Cyclophosphamide
     • Dexamethasone 1

2. Antioxidant Therapy

   • N-acetylcysteine (300 mg/kg/day for up to 3 weeks) to reduce oxidative stress 1, 3
   • Consider deferoxamine (100 mg/kg in 24 hours) in combination with N-acetylcysteine 3

Renal Management

• Monitor renal function closely - acute kidney injury occurs in approximately 50% of cases
• Provide appropriate fluid management and diuresis
• Consider hemodialysis or continuous kidney replacement therapy (CKRT) for severe renal impairment 1

Prognostic Indicators

• Plasma paraquat concentrations
• Urine and plasma dithionite tests
• Clinical features including severity of symptoms 4

Common Pitfalls and Caveats

1. Do not delay hemoperfusion - efficacy decreases significantly after 4 hours post-ingestion 1

2. Avoid excessive oxygen - high oxygen concentrations accelerate paraquat-induced lung damage by enhancing free radical production 1

3. Continue immunosuppressive therapy - premature discontinuation may lead to worsening pulmonary damage, as seen in case reports 5

4. Do not perform gastric lavage without proper precautions, as this can increase the risk of aspiration 4

5. Recognize that prognosis is poor despite treatment - paraquat poisoning has a very high case fatality rate even with optimal management 4, 6

6. Consult with poison control center - immediate consultation with regional poison center or toxicologist is recommended (1-800-222-1222 in the US) 1

Despite aggressive management, paraquat poisoning has a high mortality rate. Early recognition and rapid implementation of the above measures provide the best chance for survival.