What is the management for Cypermethrin (Cypremethrin, a synthetic pyrethroid) 10% Emulsifiable Concentrate (EC) poisoning?

Management of Cypermethrin 10% EC Poisoning

Cypermethrin poisoning requires primarily supportive care with immediate dermal decontamination, airway protection, and symptomatic management; severe cases may present with an organophosphate-like toxidrome requiring low-dose atropine and mechanical ventilation. 1

Immediate Decontamination and Stabilization

• Remove contaminated clothing and thoroughly wash exposed skin with soap and water as an essential first step, as dermal absorption contributes significantly to toxicity 1
• Secure the airway early in patients with altered mental status or coma, as aspiration pneumonitis is a serious complication occurring in approximately 17% of pyrethroid ingestions 2
• Provide mechanical ventilation if respiratory failure develops, which may be necessary in severe poisonings presenting with coma 1

Clinical Presentation Recognition

Gastrointestinal Manifestations (Most Common)

• Expect gastrointestinal symptoms in approximately 73% of cases, including sore throat, mouth ulcerations, dysphagia, epigastric pain, and vomiting 2
• These symptoms result from the combined effects of cypermethrin (20%), xylene solvent (70%), and surfactants (10%) in the EC formulation 2

Neurological Manifestations (Clinically Significant)

• Monitor for central nervous system involvement occurring in approximately 33% of cases, including confusion (13%), coma (21%), and seizures (8%) 2
• Recognize that severe cypermethrin poisoning can mimic organophosphate toxicity, presenting with an organophosphate-like toxidrome that poses a diagnostic challenge 1
• Treat seizures with benzodiazepines as first-line agents 3

Pulmonary Complications

• Watch for pulmonary abnormalities in approximately 29% of patients, including aspiration pneumonitis (most common) and pulmonary edema 2
• Aspiration pneumonitis carries significant mortality risk and requires aggressive supportive care 2

Cardiovascular Effects

• Monitor for bradycardia, which can be prolonged and symptomatic, requiring atropine therapy 4
• Cardiovascular symptoms occur in approximately 7% of cases and may include arrhythmias and shock 2
• Cypermethrin acts by delaying closure of voltage-sensitive sodium channels at higher concentrations, which can produce cardiotoxic effects 4

Specific Pharmacological Management

Atropine Use (Critical Distinction from Organophosphate Poisoning)

• Use LOW-DOSE atropine only if symptomatic bradycardia or excessive secretions are present 1, 4
• Avoid high-dose atropine protocols used for organophosphate poisoning, as cypermethrin does not cause cholinesterase inhibition and high doses may cause complications 1
• Titrate atropine to clinical effect (heart rate >60 bpm, adequate secretion control), not to the traditional organophosphate endpoint of "atropinization" 1

Supportive Care Measures

• Administer intravenous fluids for hypotension and shock 2
• Monitor and correct electrolyte abnormalities as needed 2
• Expect leukocytosis in approximately 33% of cases, which is typically not associated with infection 2
• Monitor for mild renal dysfunction (10% of cases) and hepatic dysfunction (6% of cases) 2

Critical Pitfalls to Avoid

• Do not misdiagnose as organophosphate poisoning and administer high-dose atropine, as this can lead to complications without benefit 1
• Do not use physical restraints without adequate sedation in agitated patients, as sustained restraint use without effective sedation is associated with death in severe poisoning cases 3, 5
• Do not delay dermal decontamination, as continued absorption worsens toxicity 1
• Do not assume mild initial presentation means benign course; monitor for delayed pulmonary and neurological complications 2

Advanced Life Support for Refractory Cases

• Consider VA-ECMO for persistent cardiogenic shock or cardiac arrest unresponsive to maximal supportive measures, as poisoned patients have favorable outcomes with mechanical circulatory support 3
• VA-ECMO is reasonable for persistent dysrhythmias when other treatments fail 3
• Mechanical circulatory support allows time for poison elimination through renal and hepatic clearance 3

Monitoring and Disposition

• Admit all symptomatic patients for at least 24 hours of observation, as complications can develop over time 2
• Monitor respiratory status closely for development of aspiration pneumonitis or pulmonary edema 2
• Serial neurological assessments are essential given the 33% incidence of CNS involvement 2
• Most patients make full recovery with appropriate supportive care; mortality is rare (<2%) with proper management 1, 2