Pattern of brain injury in the acute setting of human septic shock

Abstract

Background: Sepsis-associated brain dysfunction has been linked to white matter lesions (leukoencephalopathy) and ischemic stroke. Our objective was to assess the prevalence of brain lesions in septic shock patients requiring magnetic resonance imaging (MRI) for an acute neurologic change.

Method: Seventy-one septic shock patients were included in a prospective observational study. Patients underwent daily neurological examination. Brain MRI was obtained in patients who developed focal neurological deficit, seizure, coma, or delirium. Electroencephalogy was performed in case of coma, delirium, or seizure. Leukoencephalopathy was graded and considered present when white matter lesions were either confluent or diffuse. Patient outcome was evaluated at 6 months with the Glasgow Outcome Scale (GOS).

Results: We included 71 patients with median age of 65 years (56 to 76) and SAPS II at admission of 49 (38 to 60). MRI was indicated on focal neurological sign in 13 (18%), seizure in 7 (10%), coma in 33 (46%), and delirium in 35 (49%). MRI was normal in 37 patients (52%) and showed cerebral infarcts in 21 (29%), leukoencephalopathy in 15 (21%), and mixed lesions in 6 (8%). EEG malignant pattern was more frequent in patients with ischemic stroke or leukoencephalopathy. Ischemic stroke was independently associated with disseminated intravascular coagulation (DIC), focal neurologic signs, increased mortality, and worse GOS at 6 months.

Conclusions: Brain MRI in septic shock patients who developed acute brain dysfunction can reveal leukoencephalopathy and ischemic stroke, which is associated with DIC and increased mortality.

Figure 1

Flow chart. Other neurologic diseases: neurodegenerative, inflammatory and cerebrovascular disease, brain infection and endocarditis, older than 80 years. Contraindications: presence of metallic devices.

Figure 2

Severe leukoencephalopathy in a septic-shock patient in whom delirium developed. (A) Axial FLAIR at the level of the centrum semiovale, with (B) isotropic DWI map and (C) ADC map. On FLAIR images, bright and diffuse signals in the white matter extend to both hemispheres. DWI and ADC abnormalities are consistent with a vasogenic edema. ADC values measured at the level of the centrum semiovale ranged between 1.026 and 1.055 × 10^{− 3} mm² /s. The patient had a Glasgow Outcome Score of 4 at 6 months.

Figure 3

Multiple ischemic strokes in a septic-shock patient who remained comatose after discontinuation of sedation. Two large triangular hypersignals appear on FLAIR images (A) in the territory of the left sylvian artery and associated with DWI (B) and ADC map (C) abnormalities that are consistent with cytotoxic edema. Time of flight (TOF) (D) exhibits occlusion of left middle cerebral artery at M1 and M2 segments. Septic shock had been complicated by an intense disseminated intravascular coagulopathy. The patient died without recovering consciousness.

Figure 4

Diffuse and early-stage ischemia in 72-year-old septic-shock patients who developed generalized convulsive seizures without concomitant hypoxemia or hypotension. (A) DWI and the corresponding (B) ADC map show a diffuse cytotoxic edema. The absence of hypersignals on FLAIR (C) sequence shows that MRI was performed within 3 hours after the onset of ischemia. The patients died without recovering consciousness.