Neurologic Changes during Critical Illness: Brain Imaging Findings and Neurobehavioral Outcomes

Abstract

Encephalopathy and other neurologic morbidities are common in critical illness, sepsis, and prolonged mechanical ventilation. We assessed structural changes on brain imaging and neuropsychological outcomes in critically ill patients who developed neurological changes during their intensive care unit (ICU) stay. Patients who underwent brain imaging for neurological changes were included in the study. Medical, neuroradiological, and outcome data were obtained from patient medical records. Sixty-four patients underwent brain imaging for neurological changes. Forty-one (64%) patients had abnormalities on brain imaging. There were no differences for age, hospital length of stay, ICU length of stay, duration of mechanical ventilation or APACHE II scores for patients with normal compared to abnormal brain imaging. Cognitive impairments occurred in 48% of survivors and 6% developed psychiatric disorders. Our study demonstrates that abnormalities on brain imaging are common in critically ill patients. We also confirm previous findings that survivors of critical illness have cognitive impairments post-ICU discharge. This study further illustrates the adverse effects of critical illness on the brain and highlights the need for additional research in this emerging area.

Imaging in sepsis-associated encephalopathy—insights and opportunities

“…35 Correlating imaging with outcome Analysis of imaging findings from 108 critically ill patients who underwent brain imaging for unexplained neurological dysfunction revealed that 48% of surviving patients developed cognitive dysfunction, including memory changes, depression and, in one case, new psychosis. 24 Further work has shown that MRI in acutely delirious ICU-based patients demonstrates white matter hyperintensities. 36 The cohort in this latter study had persistent cognitive impairment at 3 months, but whether acute MRI changes were predictive of the incidence or severity of cognitive deficit was not examined.…”

“…24 This study included all critically unwell patients without primary brain injury. In the 64 patients studied (34 of whom had sepsis and/or pneumonia), both CT and MRI demonstrated a spectrum of changes including atrophy, white matter hyperintensities, oedema and cortical and subcortical haemorrhage.…”

“…Interestingly, no difference in sensitivity was observed between CT and MRI for the detection of oedema and haemorrhage, perhaps owing to the relatively late time of the scan (average scan time: 4.30 days post illness, range: 0.80-43.30 days), the fact that changes were nonspecific, or the small sample size. 24 Timing of imaging is perhaps the most crucial factor with regard to technique sensitivity: current guidelines suggest that MRI (specifically DWI) has greater sensi tivity than noncontrast CT for the detection of ischaemic stroke, at least within the first 12 h of symptom onset. 25 This scena rio is in contrast to acute haemorrhage, in which CT is often thought to have near-perfect sensitivity and is considered the gold standard, although T2* su sceptibilityweighted MRI may be as sensitive as CT in the acute setting.…”

Assessing the relationship between brain tissue oxygenation and neurological dysfunction in critically ill patients: study protocol

“…4 Specific cognitive domains particularly affected include memory, executive function, attention, and language. 5,6 Some form of cognitive impairment has been observed in roughly half of survivors. 5 These impairments are persistent, being observed for at least a decade after hospital discharge.…”

“…5,6 Some form of cognitive impairment has been observed in roughly half of survivors. 5 These impairments are persistent, being observed for at least a decade after hospital discharge. 7,8 These deficits have been compared to moderate traumatic brain injury or patients suffering from mild Alzheimer's disease4.…”