Secondary mania in a patient with delayed anoxic encephalopathy after carbon monoxide intoxication caused by a suicide attempt.

We report herein a female patient presenting with delayed anoxic encephalopathy after carbon monoxide (CO) intoxication. Five months after she attempted suicide in her car using burning charcoal, she showed manic symptoms including aggressive behaviors, irritability, decreased total sleep time, increased energy and sexual interest, and hyperactivity, as well as illusions and visual hallucinations related to bugs, certain animals, monsters and her ex-husband. Fluid-attenuated inversion recovery and T2-weighted images in brain magnetic resonance imaging showed white-matter hyperintensity in the frontal lobe and periventricular area. Her manic symptoms and psychotic features improved following daily administration of valproate (600 mg) and olanzapine (10 mg). These observations indicate that clinicians should monitor for delayed neuropsychiatric symptoms in patients with CO intoxication.