Brain magnetic resonance imaging unveils the history of carbon monoxide poisoning.

A 64-year-old woman was referred to our hospital because of possible viral meningo-encephalitis. Two weeks prior to admission she developed a gait disturbance followed by a fever and headache. Neurological examination showed a small steppage gait, bradykinesia, and rigidity without tremor. However, deep tendon reflexes and cognitive function were normal. Cerebrospinal fluid was normal. A test using a nasopharyngeal swab indicated active infection of influenza A virus, prompting the introduction of oseltamivir that is anti-influenzaviral drug. Magnetic resonance imaging (MRI) using T2WI showed elliptical and diffuse hyperintense lesions in the bilateral globus pallidi [Figure 1A] and cerebral white matter [Figure 1B], respectively. The lesions in the globus pallidi revealed irregular hyperintensity using T1WI. A detailed interview with her disclosed that she had accidentally inhaled carbon monoxide inhalation by an oil heater four weeks earlier.