What are the common causes of brain stem hemorrhage?
Pontine hemorrhage is usually caused by uncontrolled systemic hypertension, resulting in a sudden loss of consciousness, quadriparesis, and pinpoint pupils.
Progressive central herniation from supratentorial mass lesions can compress the brain stem and cause hemorrhage in the midline of the midbrain (Duret hemorrhage), producing coma and bilateral large and fixed pupils.
Diencephalic bleeding, such as thalamic hemorrhage, can dissect into the cerebral peduncles and midbrain, producing acute severe headache, hemiparesis, and III nerve palsy.
Small petechial hemorrhages occur in the brain stem of patients with head injuries, blood dyscrasias, or hemorrhagic disorders.
Ruptured aneurysms or arteriovenous malformations of the vertebrobasilar system may result in subarachnoid hemorrhage that injures the brain stem.