Gas Geyser-Related Carbon Monoxide Poisoning Presenting as Stroke Mimic and Syncope in Closed-Space Exposure: A Report of Two Cases

Carbon monoxide poisoning is a potentially fatal yet frequently overlooked condition owing to its vague clinical manifestations and deceptively normal pulse oximetry readings. Exposure related to gas geysers represents an under-recognized source of carbon monoxide toxicity in the Indian subcontinent, particularly in confined and poorly ventilated bathroom environments. We describe two patients with acute carbon monoxide poisoning presenting with different neurological emergencies. The first case involved a 58-year-old man with a history of prior stroke who presented with altered mental status and generalized weakness, initially raising suspicion of an acute cerebrovascular event. The second case involved a 45-year-old woman who developed syncope preceded by tremors and headache while bathing. In both instances, pulse oximetry readings were normal (98%) despite significant underlying hypoxia. Arterial blood gas analysis with CO-oximetry confirmed elevated carboxyhemoglobin levels (33% and 24.1%, respectively). Administration of high-flow normobaric oxygen led to rapid symptomatic improvement and full recovery in both patients, without the need for hyperbaric oxygen therapy. These cases highlight important diagnostic challenges, particularly the unreliability of pulse oximetry and the critical role of environmental history in identifying carbon monoxide exposure. Gas geyser-associated carbon monoxide poisoning should be considered in patients presenting with unexplained neurological symptoms or syncope in enclosed bathroom settings. Prompt recognition and treatment are essential, as this represents a preventable cause of significant morbidity and mortality.