Hemorrhagic Stroke Definition
A hemorrhagic stroke is an acute episode of focal or global neurological dysfunction caused by intraparenchymal, intraventricular, or subarachnoid hemorrhage, where the neurological dysfunction lasts for more than 24 hours. 1
Core Diagnostic Criteria
Hemorrhagic stroke requires two essential components:
- Acute neurological dysfunction that is focal (affecting a specific brain region) or global (affecting overall brain function) 1
- Documented bleeding within the intracranial vault on neuroimaging (CT or MRI showing blood in brain parenchyma, ventricular system, or subarachnoid space) 1
- Duration criterion of symptoms persisting for more than 24 hours or until death 1
Anatomical Classification
Hemorrhagic strokes are categorized by bleeding location:
Intracerebral Hemorrhage (ICH)
- Focal collection of blood within the brain parenchyma or ventricular system not caused by trauma 1
- Accounts for approximately 10-15% of all strokes 2, 3, 4
- Rapidly developing clinical signs attributable to the blood collection 1
Subarachnoid Hemorrhage (SAH)
- Bleeding into the subarachnoid space surrounding the brain 1
- Most commonly caused by ruptured cerebral aneurysms 2, 5
- Comprises approximately 3% of all strokes 2
Critical Distinction from Ischemic Stroke
Subdural hematomas are intracranial hemorrhagic events but are NOT classified as strokes 1. This is an important clinical pitfall to avoid.
Hemorrhagic transformation of ischemic stroke is classified as an ischemic stroke with hemorrhagic conversion, NOT a primary hemorrhagic stroke 1. The underlying pathology remains ischemic despite the presence of blood on imaging.
Imaging Requirements
- Brain hemorrhage is defined as evidence of blood in the brain on neuroimaging 1
- Noncontrast CT is the most common initial study with up to 89% sensitivity 4
- Brain MRI has 81% sensitivity and uses T2* or susceptibility-weighted imaging sequences for hemorrhagic lesions 1, 4
Severity Classification
Hemorrhagic strokes are classified as:
- Disabling (major): Modified Rankin Scale (mRS) ≥3 within 30 days after stroke 1
- Non-disabling (minor): mRS <3 within 30 days 1
The functional outcome classification is more clinically relevant than anatomical size for predicting morbidity and mortality 6.