Septic encephalopathy

Epidemiology
In one prospective study of 102 patients with sepsis, 66 (65%) had at least one delirium episode during their ICU stay.

EEG
One study suggested that patients with beta activity on the EEG were unlikely to have delirium, while those with delta activity were more likely. A reduction in beta activity tended to occur upon the transition from non-delirium to delirium. The presence of reactivity on EEG is associated with a lower risk of mortality (HR 0.5, 95% CI 0.2-0.9).

No episodes of seizures or NCSE were observed in one study of 102 patients with 6723 hours of vEEG. However, periodic discharges were present in 15% of patients, more commonly in those with delirium.

Imaging
One study suggested atrophy in multiple brain regions in patients with septic encephalopathy compared with age/gender matched healthy controls. However they did not match patients for comorbidities, and so this study is not convincing.

Pathophysiology
An autopsy series suggested a greater prevalence of brain microinfarction in patients who ever had an episode of sepsis during the study period (up to 10 years) compared with those who did not.