What is the management for glyphosate (herbicide) 41% poisoning?

Management of Glyphosate 41% Poisoning

Glyphosate poisoning requires aggressive supportive care as the primary treatment since there is no specific antidote, with immediate focus on airway management, decontamination, correction of metabolic acidosis and hyperkalemia, and consideration of hemodialysis for severe cases with renal failure. 1, 2

Immediate Decontamination and Personal Safety

• Healthcare providers must use appropriate personal protective equipment when caring for patients with glyphosate exposure to prevent contamination 3
• Remove all contaminated clothing immediately and perform copious irrigation with soap and water for dermal exposure 3, 4
• Gastric lavage may be performed if the patient presents within 1-2 hours of ingestion, though evidence is limited 2

Airway and Respiratory Management

• Early endotracheal intubation is critical for patients presenting with respiratory distress, impaired consciousness, or significant ingestion (>85 mL of concentrated formulation) 1, 2, 4
• Respiratory depression and pulmonary edema are common complications requiring mechanical ventilation 1, 2, 4
• Monitor for acute respiratory distress syndrome (ARDS) and aspiration pneumonia, which can develop within hours 2, 4

Cardiovascular Support

• Hypotension requiring vasopressor support is common in moderate to severe poisoning 2, 4
• Bradycardia and ventricular arrhythmias may occur, particularly in severe cases and are often pre-terminal findings 4, 5
• Establish IV access immediately and provide aggressive fluid resuscitation 2
• Continuous cardiac monitoring is essential for detecting dysrhythmias 4

Metabolic Derangements

• Severe metabolic acidosis with elevated lactate is the hallmark of significant glyphosate toxicity and requires aggressive correction 1, 2, 6
• Hyperkalemia (often >7 mEq/L) frequently accompanies severe poisoning and may persist despite standard treatment 1, 6
• Hypokalemia and hypernatremia can also develop and require monitoring 2
• The anion gap is typically elevated due to lactic acidosis 1

Renal and Hepatic Complications

• Acute kidney injury is frequent and reflects both direct toxicity and reduced organ perfusion 1, 4, 6
• Monitor creatinine, blood urea nitrogen, and urine output closely 1, 6
• Hepatic impairment with elevated ALT is common; ALT >40 U/L is an independent predictor of complications 6
• Elevated amylase and acute pancreatitis may occur several days after ingestion 6

Role of Hemodialysis

• Hemodialysis should be strongly considered for severe cases with persistent metabolic acidosis, acute kidney injury, and hyperkalemia refractory to medical management 1
• Glyphosate has excellent dialyzability with an extraction ratio of 91.8% and hemodialysis clearance of 97.5 mL/min 1
• Clinical improvement correlates with glyphosate removal via hemodialysis 1
• The effects of hemodialysis on the surfactant compound (POEA) are unknown, but hemodialysis has been associated with clinical improvement in severe cases 1

Prognostic Factors and Risk Stratification

• Age >50 years, ingestion >100 mL of concentrated formulation, chest X-ray abnormalities, and ALT >40 U/L are independent predictors of serious complications requiring ICU admission 6
• Impaired consciousness at presentation is associated with poor prognosis 1, 4
• Patients meeting these criteria should be admitted to intensive care immediately 6

Gastrointestinal Effects

• Mouth, throat, and epigastric pain with dysphagia are common due to corrosive effects 4, 5
• Gastric hemorrhage and intestinal injury can occur with concentrated formulations 5
• Monitor for gastrointestinal perforation or obstruction 4

Monitoring Timeline

• Most life-threatening complications (metabolic acidosis, respiratory failure, hypotension, acute kidney injury, hyperkalemia, seizures) develop within 24 hours of ingestion 6
• Acute pancreatitis may occur several days after ingestion and requires continued monitoring 6
• Close observation for at least 48-72 hours is recommended even in apparently stable patients 3

Common Pitfalls to Avoid

• Do not underestimate the severity based on initial presentation—patients can deteriorate rapidly within hours 2, 6
• Do not delay intubation in patients with respiratory distress or altered mental status 1, 2
• Do not withhold hemodialysis in severe cases with refractory acidosis and renal failure—early dialysis correlates with improved outcomes 1
• Do not assume mild ingestions are benign—ingestion of >85 mL of concentrated formulation (41%) is likely to cause significant toxicity 4
• Remember that toxicity is due to both glyphosate and the surfactant POEA, with the surfactant potentially contributing significantly to cardiotoxicity and tissue damage 2, 4, 5

Toxicity Mechanism

• The surfactant polyoxyethylene amine (POEA) causes cardiotoxicity and erosion of mucous membranes in the gastrointestinal and respiratory tracts 2, 4, 5
• Glyphosate causes uncoupling of oxidative phosphorylation leading to lactic acidosis 2
• Hepatic microvesicular steatosis resembling drug-induced toxicity or hypoxic stress has been observed in fatal cases 5

Contact Poison Control

• In the United States, contact poison control at 1-800-222-1222 for expert guidance on specific case management 7