Primary Causes of Hemorrhagic Stroke
Hypertension is the number one cause of intracerebral hemorrhage (ICH), particularly for deep hemorrhages in the basal ganglia and brainstem, while ruptured cerebral aneurysms are the primary cause of subarachnoid hemorrhage (SAH). 1, 2
Intracerebral Hemorrhage (ICH) Causes
ICH accounts for approximately 10-15% of all strokes and has distinct etiologies based on location 1, 3:
Deep (Hypertensive) Hemorrhages
- Hypertensive arteriopathy (arteriolosclerosis) is the predominant cause of deep ICH affecting the basal ganglia, thalamus, and brainstem 3, 4
- Small vessel disease from chronic hypertension causes deep perforator arteriopathy, leading to vessel rupture 3, 5
Lobar Hemorrhages
- Cerebral amyloid angiopathy (CAA) is the main cause of lobar hemorrhages, particularly in elderly patients 1, 3
- Arteriolosclerosis also contributes to lobar hemorrhages 3
Secondary Causes of ICH
- Vascular malformations (arteriovenous malformations, cavernomas, aneurysms) account for approximately 20% of ICH, particularly important in patients under 50 years 1, 3
- Bleeding disorders including coagulopathies and anticoagulant use 1, 2, 4
- Excessive alcohol use and liver dysfunction 1, 2
- Venous sinus thrombosis 6, 3
Subarachnoid Hemorrhage (SAH) Causes
SAH comprises approximately 3% of all strokes 1:
Primary Causes
- Ruptured cerebral aneurysms (berry or fusiform) are the leading cause of SAH 1, 2
- Aneurysmal SAH (aSAH) includes both subarachnoid blood and ICH caused by aneurysmal rupture 1
Less Common SAH Subtypes
- Intracranial dissection 1
- Perimesencephalic hemorrhage without identified aneurysm 1
- Cortical SAH without structural cause 1
Risk Factors Increasing Hemorrhagic Stroke Risk
Modifiable Risk Factors
- Uncontrolled hypertension remains the most critical modifiable risk factor, with ICH frequency increased where hypertension is untreated 6, 3
- Anticoagulant use (warfarin and newer agents) significantly increases hemorrhagic risk 1, 4, 5
- Heavy alcohol consumption 1, 2
Non-Modifiable Risk Factors
- Advanced age increases risk, particularly for amyloid angiopathy-related lobar hemorrhages 1, 2
- African-American ethnicity has higher ICH prevalence 1
- Congenital heart defects with associated hemostatic abnormalities (thrombocytopenia, platelet abnormalities, hypofibrinogenemia, coagulation factor deficiency) 1
Anatomical Substrates
- Aneurysm formation promoted by hypertension and shear stress in conditions like coarctation of the aorta, bicuspid aortic valve, or tetralogy of Fallot 1
- Arteriovenous and cavernous malformations provide structural substrate for hemorrhage 1
Critical Clinical Considerations
Exclude traumatic ICH, subdural hematomas, hemorrhage from cerebral venous thrombosis, and neoplasm-related hemorrhage when diagnosing spontaneous hemorrhagic stroke 1. These represent distinct entities requiring different management approaches.
The underlying pathophysiology differs substantially between deep and lobar hemorrhages, which has implications for recurrence risk and secondary prevention strategies 3, 5. Deep hemorrhages suggest hypertensive arteriopathy requiring aggressive blood pressure control, while lobar hemorrhages in elderly patients suggest CAA with different management considerations 3, 4.