|Year : 2015 | Volume
| Issue : 6 | Page : 816-818
Glyphosate: Surfactant herbicide poisoning - Is it mild?
K Venugopal, C Suresh, Huggi Vishwanath, Mudegoudara Lingaraja, MY Bharath Raj
Department of General Medicine, Vijayanagara Institute of Medical Sciences, Bellary, Karnataka, India
|Date of Web Publication||19-Nov-2015|
Department of General Medicine, Vijayanagara Institute of Medical Sciences, Bellary - 583 104, Karnataka
Source of Support: None, Conflict of Interest: None
Glyphosate Surfactant is a nonselective widely used herbicide in agriculture, forestry, industrial weed control, lawn, garden and aquatic environments. They have favorable toxicity with occupational and accidental exposures. The toxicity in humans is mucosal and gastrointestinal irritation, hypotension, metabolic acidosis, pulmonary insufficiency, and oliguria. Patient may appear asymptomatic for many hours before slowly lapse into a hypotensive, apparently nonhypovolaemic shock that can often ends fatally. We hereby report a case of a 25-year-old male patient who was admitted to our tertiary care hospital following suicidal consumption of around 250-300 ml of herbicide containing glyphosate (glypho; ). Initially, gastric lavage done and the patient was managed with intubation and mechanical ventilation. He also developed acute renal failure, and renal function reverted to normal after four sittings of hemodialysis. Patient was successfully treated and discharged home. This case report emphasizes on timely systemic supportive measure as the sole method of treatment since this poison has no specific antidote.
Keywords: Acute renal failure, glyphosate, herbicide, intravenous fat emulsion
|How to cite this article:|
Venugopal K, Suresh C, Vishwanath H, Lingaraja M, Bharath Raj M Y. Glyphosate: Surfactant herbicide poisoning - Is it mild?. Med J DY Patil Univ 2015;8:816-8
| Introduction|| |
Glyphosate (N-phosphonomethyl glycine) is a broad-spectrum systemic herbicide used to kill weeds, lawn, garden and aquatic environments. Glyphosate potential as herbicide was first reported in 1971. Though it is less toxic to humans, it produces a wide range of symptoms ranging from asymptomatic to death. Most of the complications are related to gastrointestinal system, and most worried complications are respiratory failure, renal failure and cardiac arrhythmias. Human toxicity is due to uncoupling of oxidative phosphorylation.
| Case Report|| |
A 25-year-old male presented to the emergency department with alleged history of suicidal consumption of around 250-300 ml of glypho; 41% (glyphosate). On admission, his pulse rate was 72 beats/min, blood pressure was 130/70 mmhg, respiratory rate was 12 per minute and saturation was 68%. Systemic examination was normal except for fine basal rales and altered mental status. His glucometer random blood sugar was 128 mg%, urea was 52 mg%, and serum creatinine was 1.8 mg%. His electrolytes revealed hyperkalemia with potassium of 5.8 mmol/L and other electrolytes were normal. Other laboratory investigations are given in [Table 1]. Gastric lavage was given to remove the unabsorbed poison. Patient was given oxygen at 6 L/min through Hudson's mask. In view of falling saturation, altered mental status and respiratory depression, patient was intubated and put on synchronized intermittent mandatory ventilation. He was treated with intravenous pantoprazole, ceftriaxone and adequate hydration. Very next day patient developed oliguric renal failure and became tachypneic. His complete blood picture revealed total leucocyte count of 10,000 cells/cumm, platelet count of 2 lakh, and hemoglobin was 13.2 g%. His renal function tests revealed urea of 110 mg% and creatinine of 7.2 mg%. In view of decreased urine output and worsening renal function patient, dialyzed through right internal jugular vein catheter. Patient was extubated on day-4, his hemodynamic condition was stable, and after four sittings of dialysis his renal function reverted to normal. Patient was discharged after a week with thorough counseling.
| Discussion|| |
Glyphosate is a broad-spectrum systemic herbicide used to kill weeds. It is a nonselective herbicide. It contains carbon and phosphorous moiety, but has no anticholinesterase effect and does not demonstrate organophosphate-like effects. The formulation most commonly available contains water, 41% glyphosate (isopropylamine salt) and 15% polyoxyethyleneamine (POEA). POEA is a surfactant, which aids penetration of the chemical into the plant tissue.
Glyphosate's mode of action is to inhibit an enzyme involved in the synthesis of the aromatic amino acids tyrosine, tryptophan and phenylalanine through shikimic acid pathway,  In humans the toxicity is less due to the absence of shikimic acid pathway.  Proposed mechanisms of glyphosate toxicity to humans include uncoupling of oxidative phosphorylation  and glyphosate-or POEA-mediated direct cardiotoxicity. 
Dermal exposure to ready-to-use glyphosate formulations can cause irritation and photo-contact dermatitis. These effects are probably due to the preservative Proxel (benzisothiazolin-3-one). Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate. Corrosive effects - mouth, throat and epigastric pain and dysphagia - are common. Respiratory distress, impaired consciousness, pulmonary edema, infiltration on chest X-ray, shock, arrhythmias, renal failure requiring hemodialysis, metabolic acidosis, and hyperkalemia may occur in severe cases. Bradycardia and ventricular arrhythmias often present prior to death. 
Diagnosis of the poisoning is mainly by the history and exposure can be measurement in blood or urine by gas chromatography and high-performance liquid chromatography. There is no specific antidote for the poisoning. Mainstay of treatment is supportive care. Gastric lavage using activated charcoal may be beneficial if performed within 1 h of ingestion of poison. There is no clear evidence that, it will prevent further absorption of the poison. Early renal replacement therapy may improve prognosis, but there is no evidence to support this and requires identification of those at risk.  Intravenous fat emulsion (IFE) has been used in the management of severe local anesthetic toxicity, calcium channel blockers, tricyclic antidepressants and beta blockers. A study by Han et al.  demonstrated the effectiveness of IFE in severe poisoning patient who was hypotensive and refractory to inotropic support later showed recovery after administration of IFE, surviving to hospital discharge without further complications.
| Conclusion|| |
Even though, the toxicity in the humans are minimal, life-threatening complications have been identified and reported. Observation of the patient and early recognition of the complications including renal failure, respiratory failure and arrhythmias will reduce the mortality. This case report emphasis the early development of renal and respiratory failure in our attempted suicidal consumption patient and prompt treatment with renal replacement therapy and ventilator support saved the life of the patient. This case report also emphasis that one should not neglect this nonorgan phosphorous compound poisoning and observation of the patient for complications if neglected it can take the lives.
| References|| |
Mahendrakar K, Venkategowda PM, Rao SM, Mutkule DP. Glyphosate surfactant herbicide poisoning and management. Indian J Crit Care Med 2014;18:328-30.
Bates N, Campbell A. Glyphosate. In: Campbell A, editor. Handbook of Poisoning in Dogs and Cat. 1 st
ed. England: Blackwell Science Ltd.; 2000. p. 135-8.
Lee HL, Kan CD, Tsai CL, Liou MJ, Guo HR. Comparative effects of the formulation of glyphosate-surfactant herbicides on hemodynamics in swine. Clin Toxicol (Phila) 2009;47:651-8.
Sawada Y, Nagai Y, Ueyama M, Yamamoto I. Probable toxicity of surface-active agent in commercial herbicide containing glyphosate. Lancet 1988;1:299.
Stella J, Ryan M. Glyphosate herbicide formulation: a potentially lethal ingestion. Emerg Med Australas 2004;16:235-9.
Han SK, Jeong J, Yeom S, Ryu J, Park S. Use of a lipid emulsion in a patient with refractory hypotension caused by glyphosate-surfactant herbicide. Clin Toxicol (Phila) 2010;48:566-8.