Overview of stroke

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Last reviewed: 24 Jun 2025
Last updated: 01 May 2024

This page compiles our content related to stroke. For further information on diagnosis and treatment, follow the links below to our full BMJ Best Practice topics on the relevant conditions and symptoms.

Introduction

ConditionDescription

Ischemic stroke

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Regardless of the specific etiology, ischemic 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 ischemic strokes are caused by cerebral sinus or cortical vein thrombosis. There are more than 100,000 strokes in the UK each year causing 38,000 deaths, making it a leading cause of death and disability.[1][2]​ Most common symptoms are partial or total loss of strength in upper and/or lower extremities, expressive and/or receptive language dysfunction, sensory loss in upper and/or lower extremities, visual field loss, slurred speech, or difficulty with fine motor coordination and gait. Risk factors strongly associated with ischemic stroke include older age, history of transient ischemic attack or previous ischemic stroke, family history of stroke, hypertension, smoking, diabetes mellitus, atrial fibrillation, comorbid cardiac conditions, carotid artery stenosis, sickle cell disease, and dyslipidemia.​​​​​​​​​​​​​​​​​[3]

Carotid artery stenosis

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Narrowing of the lumen of the carotid artery. Cause of a minority of ischemic strokes. Atherosclerotic plaque in the cervical carotid artery is the most common cause. Plaque disruption and atheroembolization into the intracranial circulation is the most common mechanism for stroke. One systematic review and meta-analysis estimated the global prevalence of carotid stenosis in people ages 30 to 79 years in 2020 to be 1.5%.[4] People presenting with symptoms may include those with transient ischemic attack, stroke, and transient monocular blindness (amaurosis fugax). Strong risk factors include older age, smoking, and history of cardiovascular disease.[5][6][7]​​ ​​

Transient ischemic attack

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A transient ischemic attack (TIA) is a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction.[8]​ TIA should be suspected in a patient who presents with sudden-onset, focal neurologic deficit that resolves spontaneously and cannot be explained by another condition such as hypoglycemia. Until the neurologic symptoms and signs have resolved completely you cannot assume the event is a TIA, and you should proceed with investigations and management for a working diagnosis of stroke.[9] The age-adjusted annual incidence rate for TIA in the UK has been estimated at 190 cases per 100,000 population.[10]​ TIAs have considerable risk of early recurrent cerebral ischemic events.[11] Strong risk factors for TIA include atrial fibrillation, valvular heart disease, carotid stenosis, intracranial stenosis, congestive heart failure, hypertension, hyperlipidemia, diabetes mellitus, cigarette smoking, alcohol-use disorder, and advanced age.[12]​​[13]​​[14]​​[15][16][17][18]​​​​ ​​​​Presentation of TIA is dictated by the region of brain supplied by the obstructed vessel. Evaluation and initiation of secondary prevention should occur rapidly.

Stroke due to spontaneous intracerebral hemorrhage

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Intracerebral hemorrhage (ICH) is an emergency. ICH is caused by vascular rupture with bleeding into the brain parenchyma, resulting in a primary mechanical injury to the brain tissue. The global prevalence of ICH was 18.88 million cases in 2020.[19]​ Suspect stroke in a patient with sudden onset of focal neurologic symptoms: unilateral weakness or paralysis in the face, arm, or leg, unilateral sensory loss, dysarthria or expressive or receptive dysphasia, vision problems (e.g., hemianopia), headache (sudden severe and unusual headache), difficulty with coordination and gait, vertigo or loss of balance, especially with the above signs.[20]​ Strong risk factors include hypertension, older age, family history of ICH, hemophilia, cerebral amyloid angiopathy, anticoagulation, use of illicit sympathomimetic drugs, vascular malformations, and Moyamoya syndrome.[21][22][23][24][25][26][27][28]

Cerebral aneurysm

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A focal abnormal dilation of the wall of an artery in the brain. Typically asymptomatic until ruptured, resulting in a subarachnoid hemorrhage. Screening with noninvasive neuroangiography is recommended for at-risk populations. Autopsy studies indicate that cerebral aneurysms are fairly common in adults, with a prevalence ranging between 1% and 5%.[29][30]​​​ Strong risk factors include smoking, family history, female sex, age, and previous subarachnoid hemorrhage.​[31]​​

Subarachnoid hemorrhage

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A medical emergency where there is bleeding into the subarachnoid space. The most common cause of nontraumatic subarachnoid hemorrhage is rupture of an intracranial aneurysm.[32]​ ​In the UK, more than 15,000 diagnoses were reported in 2021-2022.[33]​ Presents as a sudden, severe headache that peaks within 1 to 5 minutes (thunderclap headache) and lasts more than an hour; typically alongside vomiting, photophobia, and nonfocal neurologic signs. Strong risk factors include hypertension, smoking, family history, and autosomal dominant polycystic kidney disease.[34]​​​[35][36]

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