Brainstem hemorrhage, like hemorrhages in other parts of the brain, also has a period of cerebral edema. Cerebral edema is primarily caused by direct injury to brain tissue following hemorrhage, local ischemic and hypoxic changes, local metabolic products, and some damage to the vascular endothelium. Generally, the edema becomes apparent three days after the hemorrhage, peaks between three to seven days, begins to subside after ten days, and completely resolves around fourteen to fifteen days. However, there are exceptions, such as cases where edema occurs shortly after injury or within a few hours, and the peak period of edema lasts for several weeks, or even up to a month without complete resolution.