What causes brainstem hemorrhage?

Brainstem hemorrhage is caused by factors such as hypertension and small artery sclerosis, as well as conditions including cerebral arteriovenous malformations, aneurysms, blood disorders, hemorrhagic transformation after infarction, cerebral amyloid angiopathy, moyamoya disease, cerebral arteritis, anticoagulant or thrombolytic therapy, and stroke. Long-term hypertension leads to hyaline degeneration and fibrous necrosis of small cerebral arteries, reducing vascular elasticity. When blood pressure suddenly increases, these weakened vessels are prone to rupture and bleed.