Brain Injury From Cerebral Hypoperfusion

Cerebral hypoperfusion can cause a range of brain injuries. When mild, it can lead to syncope, a temporary loss of consciousness characterized by rapid onset, brief duration, and full recovery. The causes include reflex mediated (the most common), orthostatic hypotension, and cardiac abnormalities. More prolonged hypoperfusion, together with extracranial vascular disease, can cause selective damage to vulnerable areas of the cerebral cortex that lie in between vascular territories and can lead to watershed territory infarcts. Patients often present with specific syndromes including transcortical motor or sensory aphasia, man-in-the-barrel syndrome, and Balint syndrome. In cardiac arrest a sudden ventricular arrhythmia or asystole leads to the immediate loss of cardiac output and hypoxic-ischemic brain injury. The outcome is variable but predictors of poor outcome include absent brainstem reflexes or absent or extensor motor responses at 72. h and early myoclonus status epilepticus.