Methomyl Poisoning Presenting with Decorticate Posture and Cortical Blindness
A 61-year-old Taiwanese man was admitted to our emergency room because of altered mental status. His wife informed the medical personnel that her husband had quarreled with their son a few days previously, and had remained in a bad mood since the incident. That morning, when she awoke at approximately 6:30 am, she found her husband lying on the bathroom floor. An empty can of liquid methomyl was beside him. She estimated that her husband had swallowed approximately 300 cm3 of methomyl. Further examination revealed depressed consciousness (Glasgow Coma Scale, E1M1V1). The patient’s eyes had pinpoint pupils and his blood pressure and pulse were absent. He was also unable to breathe spontaneously. Cardiac arrest was confirmed and the patient underwent cardiac massage for 11 minutes. He was also intubated to maintain his breathing. After cardiopulmonary resuscitation (CPR), his vital signs of blood pressure, temperature, pulse rate, and respiratory rate, returned to within reference rages: 110/70 mmHg, 36.7°C, 68 beats/min, and 29 breaths/min, respectively. An emergency doctor provided a gastric lavage. The patient was sent to an intensive care unit for close observation. On the second day of admission, he regained consciousness and could open his eyes spontaneously and under instruction. However, his posture was irregular (upper extremities flexed upwardly and lower extremities extended). We instructed him to extend his upper extremities but he was unable to follow this order. On the sixth day of admission, the patient was extubated after showing general improvement in condition. However, he started to complain of unclear vision. Although he could sense an object in front of him and could recognize the object when placed in his hands, he was unable to identify the object correctly. Suspecting an eye problem, we consulted an ophthalmologist to determine whether any ocular abnormality existed. A fundoscopy and other eye testing revealed no obvious abnormalities. A neurological examination was also conducted, confirming decorticate posture and cortical blindness. Other neurological findings, including those regarding the patient’s motor and sensory systems, coordination, deep tendon reflexes, and cranial nerves, were all unremarkable. Therefore, we arranged a brain MRI to eliminate possible central visual pathway lesions. The brain MRI revealed lesions in the bilateral tips of the occipital lobe areas (). We hydrated the patient with normal saline and administered 75 mg of aspirin once daily and 150 mg of piracetam twice daily. He remained in the hospital for 3 weeks, after which he was discharged for neurology outpatient clinical follow-up. He attended outpatient clinical follow-ups for 2 months after discharge and his vision improved, whereas his decorticate posture remained refractory. A second brain MRI was performed, revealing the disappearance of the bilateral occipital lobe lesions and symmetrical putaminal high signal abnormalities (). This patient continues to attend regular follow-ups at the clinic.