Two Primary Types of Stroke
Yes, you are absolutely correct—there are two main types of stroke: ischemic stroke (caused by blocked blood flow to the brain) and hemorrhagic stroke (caused by bleeding in or around the brain). 1
Ischemic Stroke (88% of all strokes)
Ischemic strokes result from blocked blood vessels that prevent blood from reaching brain tissue, leading to cerebral infarction 1. This is by far the most common type, accounting for approximately 85-88% of all strokes 2, 3.
Common causes include:
- Large-vessel atherosclerosis (20% of ischemic strokes) affecting the carotid or vertebrobasilar arteries
- Small-vessel disease (25%) causing lacunar strokes in deep brain structures
- Cardiogenic embolism (20%), most frequently from atrial fibrillation
- Cryptogenic strokes (30%) where the exact cause remains unknown 1
Hemorrhagic Stroke (12% of all strokes)
Hemorrhagic strokes occur when blood vessels rupture, causing bleeding in or around the brain 1. These are further divided into:
Intracerebral Hemorrhage (ICH)
- Accounts for 10% of all strokes 1, 4
- Hypertension is the #1 cause 1
- Other causes: bleeding disorders, vascular malformations, excessive alcohol use, liver dysfunction, anticoagulation 1
Subarachnoid Hemorrhage (SAH)
Clinical Importance of Distinguishing Types
The distinction between ischemic and hemorrhagic stroke is critical because treatments are fundamentally different—antithrombotic medications that help ischemic stroke can be catastrophic in hemorrhagic stroke 4. This is why immediate brain imaging (CT or MRI) is essential for all suspected stroke patients to differentiate between these two types before initiating treatment 5, 2.
The pathophysiology differs substantially: ischemic strokes cause injury through oxygen deprivation to brain tissue, while hemorrhagic strokes cause damage through both direct pressure effects from the expanding hematoma and toxic effects of blood breakdown products 6.