This article provides an overview of the classification of stroke based on underlying pathophysiology and clinical presentation. You can also download a PDF summary of our Bamford Stroke classification guide.
Types of stroke
Strokes can be classified into twomajorcategories: ¹
Ischaemic stroke (87%)
Haemorrhagic stroke (13%)
Ischaemicstrokes occur when the bloodsupply to an area of brain tissue is reduced, resulting in tissuehypoperfusion.
There are several potential mechanisms which can result in an ischaemicstroke including:
Embolism: an embolus originating somewhere else in the body (e.g. the heart) causes obstruction of a cerebral vessel, resulting in hypoperfusion to the area of the brain the vessel supplies.
Thrombosis: a blood clot forms locally within a cerebral vessel (e.g. due to atherosclerotic plaque rupture).
Systemic hypoperfusion: blood supply to the entire brain is reduced secondary to systemic hypotension (e.g. cardiac arrest).
Cerebral venous sinus thrombosis: blood clots form in the veins that drain the brain, resulting in venous congestion and tissue hypoxia.
Haemorrhagic strokes occur secondary to rupture of a blood vessel or abnormal vascular structure within the brain.
There are two sub-types of haemorrhagic stroke known as intracerebralhaemorrhage and subarachnoidhaemorrhage.
Intracerebral haemorrhage involves bleeding within the brain secondary to a ruptured blood vessel. Intracerebral haemorrhages can be intraparenchymal (within the brain tissue) and/or intraventricular (within the ventricles).
Subarachnoid haemorrhage is a type of stroke caused by bleeding outside of the brain tissue, between the pia mater and arachnoid mater.
Blood supply of the cerebrum
The anterior, middle and posteriorcerebralarteries each supply a specific territory of the brain:
The anterior cerebral arteries supply the anteromedial area of the cerebrum.
The middle cerebral arteries supply the majority of the lateralcerebrum.
The posterior cerebral arteries supply a mixture of the medial and lateral areas of the posteriorcerebrum.
Bamford classification of ischaemic stroke
The most commonly used classification system for ischaemic stroke is the Bamfordclassification system (also known as the Oxford classification system). This system categorises stroke based on the initial presenting symptoms and clinical signs. This system does not require imaging to classify the stroke, instead, it is based on clinical findings alone.
Total anterior circulation stroke (TACS)
A totalanteriorcirculationstroke (TACS) is a large cortical stroke affecting the areas of the brain supplied by both the middle and anteriorcerebralarteries.
All three of the following need to be present for a diagnosis of a TACS:
Unilateral weakness (and/or sensory deficit) of the face, arm and leg