Stroke is defined as an acute neurological deficit lasting more than 24 hours and caused by cerebrovascular aetiology. It is subdivided into ischaemic stroke (caused by vascular occlusion or stenosis) and haemorrhagic stroke (caused by vascular rupture, resulting in intra-parenchymal and/or subarachnoid haemorrhage). Ischaemic stroke accounts for 87% of all stroke cases, haemorrhagic stroke for 10%, and subarachnoid haemorrhage for 3%.
Regardless of the specific aetiology, ischaemic stroke occurs when blood supply in a cerebral vascular territory is critically reduced due to occlusion or critical stenosis of a cerebral artery. A minority of ischaemic strokes are caused by cerebral sinus or cortical vein thrombosis. Risk factors strongly associated with ischaemic stroke include older age, history of transient ischaemic attack, history of ischaemic stroke, family history of stroke at a young age, hypertension, smoking, diabetes mellitus, atrial fibrillation, comorbid cardiac conditions, carotid artery stenosis, sickle cell disease, and dyslipidaemia.
Cause of a minority of ischaemic strokes. Strong risk factors include older age, smoking, and history of cardiovascular disease. Carotid revascularisation of moderate- or high-grade recently symptomatic carotid artery stenosis prevents future stroke. The benefit of revascularisation for asymptomatic stenosis is less certain.
Transient ischaemic attack (TIA) should be suspected in anyone who presents with sudden-onset, focal neurological deficit that has completely resolved within 24 hours of onset and cannot be explained by another condition such as hypoglycaemia. TIAs have considerable risk of early recurrent cerebral ischaemic events. Strong risk factors include atrial fibrillation, valvular heart disease, congestive heart failure, hypertension, diabetes mellitus, carotid stenosis, other significant illnesses (such as a hypercoagulable state or vasculitis such as temporal arteritis), cigarette smoking, alcohol-use disorder, and older age. Evaluation and initiation of secondary prevention should occur rapidly.
Intracerebral haemorrhage is caused by vascular rupture with bleeding into the brain parenchyma, resulting in a primary mechanical injury to the brain tissue. In 2017, the global prevalence of intracerebral haemorrhage (ICH) was 17.9 million people. Strong risk factors include hypertension, older age, family history of ICH, haemophilia, cerebral amyloid angiopathy, anticoagulation, use of illicit sympathomimetic drugs, vascular malformations, and Moyamoya syndrome.
Typically asymptomatic until ruptured, resulting in a subarachnoid haemorrhage. Screening with non-invasive neuroangiography is recommended for at-risk populations. Strong risk factors include smoking, moderate-high level alcohol consumption, family history, previous subarachnoid haemorrhage, and heritable connective tissue disease.
A medical emergency where there is bleeding into the subarachnoid space. The most common cause of non-traumatic subarachnoid haemorrhage is rupture of an intracranial aneurysm. Strong risk factors include age ≥50 years old, female sex, hypertension, smoking, family history, alcohol misuse, and autosomal dominant polycystic kidney disease.
BMJ Publishing Group
This overview has been compiled using the information in existing sub-topics.
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