Abstract
Cerebral edema is the pathologic excess of intracellular and/or extracellular fluid in the brain that can be associated with neurological morbidity and mortality. Cerebral edema is classified as vasogenic, cytotoxic, interstitial, or osmotic. More than one form of cerebral edema can occur contemporaneously in a disease state. Dysfunction of the blood-brain barrier, altered cellular metabolism, osmotic homeostasis, and/or the glymphatic system underlies the development and progression of cerebral edema. Vasogenic edema occurs when the blood-brain barrier loses its integrity and becomes abnormally permeable, allowing fluid egress from the vasculature and accumulation in the extracellular spaces of the brain parenchyma. Cytotoxic edema results from energy failure that disrupts cellular ion pump homeostasis and leads to intracellular swelling. Interstitial edema is caused by cerebrospinal fluid driven under increased pressure (transependymal flow) from the ventricles into adjacent interstitial spaces of the brain parenchyma. Osmotic edema arises as a result of systemic hypo-osmolar states (relative to brain) that cause fluid to shift into the brain parenchyma along an osmotic gradient. MRI of cerebral edema can assist in differentiation of vasogenic, cytotoxic, and interstitial edema. Management of cerebral edema is targeted at the specific pathology and mitigating secondary injury. © 2023 Elsevier Inc. All rights reserved.