Demystifying the fog – CT and MRI confirming the diagnosis of carbon monoxide poisoning by gas geysers

• Loss of consciousness was observed in many people while taking bath.
• These bathrooms were equipped with LPG based water heaters and had poor ventilation.
• Comparison of imaging findings of such patients with that of CO poisoning was done.
• The imaging findings of both CO poisoning and these patients were similar.
• CO produced by LPG based water heater caused this loss of consciousness.

ObjectiveUnexplained loss of consciousness was observed in many people while taking bath in small sized, ill ventilated bathrooms equipped with liquefied petroleum gas (LPG) based water heaters (also known as gas geysers). This led many investigators to hypothesize that the gases produced during incomplete combustion of LPG, especially carbon monoxide was the cause behind these neurological events. The objective of this study was to observe the brain computed tomography (CT) and magnetic resonance imaging (MRI) findings of such patients and correlate these findings with brain imaging in carbon monoxide (CO) poisoning.Material and methodsA total of 10 patients who were admitted to our hospital with a history of loss of consciousness in the bathroom fitted with LPG based water heaters were retrospectively included in our study. The brain CT was performed on 64 slice scanner. MRI studies were done on a 1.5 T MR scanner using routine brain sequences, including T1 weighted, T2 weighted Fluid Attenuated Inversion Recovery (FLAIR) and gradient echo in the axial sequences. T2 weighted images were acquired in coronal and also in sagittal planes. CT and MRI images of such patients were analyzed by two radiologists having 11 years of experience in neuroimaging and the findings were tabulated. The radiologists specifically observed the areas of brain involvement and commented whether the imaging pattern in gas geyser poisoning correlated with those observed in imaging of carbon monoxide poisoning.ResultsGlobus pallidus was the most frequent site of involvement, which was seen in 50% of the patients (n=5). This was followed by putamen (n=3) and caudate nucleus (n=2). Cerebral edema was observed in two patients. Cerebellar lesions were seen in one of the patients (n=1). The areas of brain affected by gas geyser poisoning on CT and MRI were similar to that observed in carbon monoxide poisoning.ConclusionThe distribution of brain lesions produced by “gas geyser poisoning”, very closely correlated with that of brain involvement in carbon monoxide intoxication. Thus, we conclude that it is the CO produced by incomplete combustion of LPG in poorly ventilated washrooms that leads to various neurological symptoms in these patients. The purpose of this paper is to create awareness among radiologists, emergency medicine physicians, neurologists, general physicians and the public about the existence of gas geyser poisoning and to further elaborate the imaging findings in these patients.