Glufosinate Herbicide Intoxication Causing Unconsciousness, Convulsion, and 6th Cranial Nerve Palsy
A 34-yr-old man ingested 150 mL of glufosinate ammonium herbicide on November 06, 2012. Formulation of the herbicide is as follows: glufosinate ammonium, 18%; alcohol (C12-14), ethoxylated monoether with sulfuric acid, sodium salts (CAS No. 68909-66-0) as surfactants, 28.5%; antifoaming agent and coloring agent, 0.5%; and water, 53%. One hour after ingestion, gastric lavage was performed at the primary care clinic. At 5 hr after ingestion, the patient underwent hemodialysis for 2 hr (). Eight hours after ingestion, the patient complained of diplopia. Eleven hours after ingestion, the patient exhibited a stuporous mental state and was transferred to the toxicology center in our hospital. Physical examination showed a blood pressure of 100/70 mmHg and pulse rate of 76 beats/min. Chest radiography and electrocardiography showed no abnormalities. Initial laboratory findings, including complete blood cell count, liver function test, urea nitrogen, creatinine, and electrolytes, were within normal limits.\nAbout 1 hr after arrival at our emergency room, bronchial secretion increased and respiration become shallow with hypoxia (arterial oxygen tension [PaO2], <70 mmHg) and CO2 retention (arterial carbon dioxide tension [PaCO2]>50 mmHg). Tracheal intubation was performed and mechanical ventilation was initiated.\nAccording to the protocol for the management of large amounts of herbicide ingestion, a loading dose of an intravenous lipid emulsion (ILE) was administered, and subsequently, the patient was maintained on lipid emulsion infusion.\nOn the second day of the hospital stay, the patient exhibited drowsiness. In the intensive care unit, the patient was treated with hemoperfusion for extracorporeal elimination of toxic ingredients of the herbicide, and was put on mechanical ventilation for apnea. The patient developed tonic-type convulsions, for which he received lorazepam injection. On the fifth day of the hospital stay, the patient underwent successful weaning trials and was extubated, after which he complained of double vision. Ophthalmologic examination showed that he had esotropia (10 prism diopters), and the angle increased while gazing to the right and left. The Lancaster red-green test () showed incomitant uncrossed diplopia at 9 different positions of gaze, and the deviation increased for both the right and left gaze (). These results suggest that the patient had bilateral sixth cranial nerve palsy. A second test performed 1 day later showed an improvement in the esodeviation with symptomatic relief. On the seventh hospital day, brain magnetic resonance imaging (MRI) was performed to rule out organic disease. No structural abnormality was found, especially in the intracisternal, intracavernous, and intraorbital portions through which the sixth cranial nerve passes. In addition, diplopia and nystagmus intensity began to subside. On the ninth hospital day, diplopia disappeared and the nystagmus intensity decreased further. The patient was discharged on the eleventh day without any ophthalmologic abnormality or abnormal blood chemistry results.