Carbon Monoxide as a Hidden Environmental Trigger of Seizure: A Case Report

Introduction: This study aimed to report a case of covert carbon monoxide (CO) poisoning presenting with seizure as the sole initial symptom. It also aimed to emphasize the diagnostic difficulty caused by the nonspecific clinical manifestations of CO poisoning. Delayed diagnosis in such cases may lead to serious morbidity or mortality. Therefore, CO poisoning should be considered in patients presenting with unexplained seizures. Case Presentation: A 32-year-old man with no contributory medical history presented to the hospital with decreased consciousness, seizures, blurred vision, impaired balance, and hearing loss after spending the night alone at home. When he arrived at the hospital, he had hearing loss and balance disturbance. Nasal oxygen therapy (4–6 L/min) was administered. Initial lab results and brain imaging were unremarkable, and a diagnosis of "seizure of unknown origin" was made. A toxicology consultation and fire department inspection revealed CO levels over 150 ppm due to a leak from the central heating system. Conclusion: This case demonstrates that CO poisoning may present solely with acute neurological symptoms like seizures, without the classic signs of exposure. In patients with unexplained neurological findings, especially those who have spent time in enclosed spaces with central heating, CO poisoning should be considered. Training healthcare staff, increasing public awareness, and using CO detectors are crucial for prevention and timely diagnosis.