The rear portion of the brain is known as the brain stem. It conducts impulses from the brain to the rest of the body, enervates the 3-12 facial nerves and is also involved in the control of breathing, the cardiovascular system, sensitivity, awareness and alertness. Bleeding in this area almost always has life threatening complications.
Trauma
According to the experts at the Mayo Clinic, trauma is the leading cause of intracranial bleeding. Car accidents and bumps to the head are common causes of bleeding into the brain stem. These injuries do not necessarily leave any outwardly visible traces. Brain stem bleeding is more common in elderly individuals and people using blood thinners and anticoagulants such as aspirin.
Hypertension
High blood pressure is also a common cause of bleeding into the brain stem. In cases of uncontrolled hypertension a hemorrhage is possible when a blood vessel burst causes blood to seep into the intracranial space and place pressure on the brain stem, cutting off blood supply to portions of the brain. This condition can be fatal.
Infection
Bacterial or viral infections can be a cause of bleeding into the brain stem. These conditions cause a buildup of blood in the intracranial space that can place strain on the blood vessels and brain tissue. The vessels can tear and bleed.
