Pathogenetic role of circulatory factors in brain edema development

Sufficient experimental evidence has been accumulated at present, proving that changes in cerebral blood circulation are largely involved in brain edema development. On the one hand, they might be an immediate cause of edema, e.g., a significant rise of the systemic arterial pressure surpassing the limits of cerebral blood flow autoregulation, or cerebral ischemia damaging brain tissue and the blood-brain barrier. On the other hand, circulatory changes, e.g., systemic arterial and venous pressure variations, as well as changes in cerebrovascular resistance or in the microcirculation of cerebral tissue, might be the factors which affect in different ways the development of edema of various etiologies. The effects of these circulatory changes may have dual implications, being either malignant, i.e., aggravating edema development, or compensatory, i.e., restricting or in some cases even eliminating brain edema. Knowledge of the circulatory changes is an essential tool in neurosurgical practice, providing for effective treatment of this severe pathological process in the brain.