What is the management for pyrethrum toxicity?

Management of Pyrethrum Toxicity

The management of pyrethrum toxicity is primarily supportive and symptomatic, as there is no specific antidote available. 1 Prompt decontamination and careful monitoring of vital signs are essential components of treatment.

Initial Management

• Decontamination:

  • For dermal exposure: Remove contaminated clothing and wash affected skin thoroughly with soap and water 2
  • For ocular exposure: Irrigate eyes with copious amounts of water or saline
  • For ingestion: Consider activated charcoal within 1-2 hours of ingestion if patient is alert 2

• Airway Management:

  • Early endotracheal intubation for life-threatening poisoning 3
  • Position unconscious patients in left lateral head-down position 2
  • Provide mechanical ventilation as needed 2

Symptomatic Treatment

For Type I Pyrethroid Syndrome (Tremors)

• Benzodiazepines (e.g., diazepam 5-10 mg IV) for tremors and agitation 4
• Antihistamines for allergic reactions and pruritus 1
• Topical application of vitamin E (dl-alpha tocopherol acetate) may reduce paraesthesiae 1

For Type II Pyrethroid Syndrome (Choreoathetosis and Salivation)

• Benzodiazepines for seizure control 4
• Atropine for excessive salivation: 1-2 mg IV, doubled every 5 minutes as needed 2
• Supportive care for other symptoms 4

Monitoring and Supportive Care

• Continuous cardiac monitoring for at least 24-36 hours 2
• Serial assessment of vital signs and mental status 2
• Monitor for respiratory depression, which may require ventilatory support 1
• Monitor for hypersensitivity reactions, particularly in the respiratory tract 5
• Maintain fluid and electrolyte balance 2

Special Considerations

• Paraesthesiae (especially facial) are common with dermal exposure and typically resolve within 12-24 hours without specific treatment 1
• Symptoms may be exacerbated by heat, sunlight, scratching, sweating, or application of water 1
• Severe poisoning with coma and convulsions requires intensive care management 1
• For patients with mixed exposures (particularly with organophosphates), consider appropriate antidotes for the co-ingested substances 4

Prognosis

Most patients with pyrethrum toxicity recover completely within 6 days with appropriate supportive care 1. Mortality is rare but has been reported in cases of massive ingestion or when there is significant respiratory involvement 5.

Common Pitfalls to Avoid

• Failing to use appropriate personal protective equipment when caring for patients with external pyrethroid exposure 3
• Underestimating the potential for allergic reactions, which can be more pronounced with natural pyrethrins than with synthetic pyrethroids 6
• Delaying treatment of seizures or respiratory symptoms, which are the principal life-threatening features 1
• Administering anything by mouth to unconscious patients 2

When to Consult Poison Control

Contact regional poison centers for expert guidance (United States: 1-800-222-1222; Canada: Provincial poison centers) 2, especially for severe cases or when there is uncertainty about management.