Partial recovery from cortical blindness following carbon monoxide intoxication

Patients with carbon monoxide (CO) intoxication may show neurological signs such as headache, seizures, extrapyramidal findings, and coma. However, cortical blindness is rare in these cases. This study describes a woman exhibiting confusion and axial rigidity after CO intoxication. Ten days after intoxication, her pupils were isonormocoric and reactive to light. A fundoscopic examination was normal, but visual acuity was light-perception in both eyes. There were diffuse EEG slow waves. Magnetic resonance imaging (MRI) demonstrated bilateral hyperintensity in the basal ganglia. The P100 latencies of visual evoked potentials (VEP) were increased and dispersed. One year later, the patient's visual acuity was almost normal and VEPs showed mild dispersion in P100 latencies. The authors found this case of interest because cortical blindness due to CO intoxication is only rarely seen with a relatively good outcome.