Stroke

Stroke
Name	Stroke
Synonyms	Cerebrovascular accident (CVA), brain attack
Caption	A CT scan showing an ischemic stroke (dark area) in the brain.
Field	Neurology, Neurosurgery, Vascular surgery
Symptoms	Inability to move or feel on one side of the body, problems understanding or speaking, dizziness, loss of vision to one side
Complications	Persistent vegetative state, pneumonia, deep vein thrombosis
Onset	Older age
Duration	Long term
Types	Ischemic, hemorrhagic
Causes	Ischemia, hemorrhage
Risks	Hypertension, tobacco smoking, obesity, diabetes mellitus, atrial fibrillation
Diagnosis	Based on symptoms with medical imaging
Differential	Hypoglycemia
Prevention	Blood pressure control, statins, smoking cessation, anticoagulants for atrial fibrillation
Treatment	Thrombolysis (ischemic), thrombectomy (ischemic), neurosurgery (hemorrhagic)
Medication	Aspirin, clopidogrel, tissue plasminogen activator
Prognosis	Variable; leading cause of adult disability
Frequency	12.2 million per year (2019)
Deaths	6.55 million (2019)

Stroke. A stroke is a medical condition where poor blood flow to the brain results in cell death, leading to long-term neurological disability and being a leading cause of death globally. It is primarily categorized into two main types: ischemic, caused by blockage of a blood vessel, and hemorrhagic, caused by bleeding. Rapid diagnosis and intervention are critical, as treatments like thrombolysis and mechanical thrombectomy are highly time-sensitive.

Signs and symptoms

Symptoms often appear suddenly and can include unilateral weakness or numbness, facial drooping, and aphasia. Visual disturbances like homonymous hemianopia are common, and patients may experience severe headache or vertigo. The National Institutes of Health Stroke Scale is a standardized tool used by clinicians to quantify impairment. Specific syndromes, such as those from occlusion of the middle cerebral artery or basilar artery, present with distinct clinical pictures recognized by organizations like the American Heart Association.

Causes and risk factors

The primary cause of ischemic stroke is atherosclerosis leading to thrombosis or embolism, often from the heart in conditions like atrial fibrillation or rheumatic heart disease. Hemorrhagic strokes are frequently due to hypertension or cerebral aneurysm rupture. Major modifiable risk factors include diabetes mellitus, hyperlipidemia, and tobacco smoking, while non-modifiable factors include advanced age and family history. Landmark studies like the Framingham Heart Study have been instrumental in identifying these risks.

Pathophysiology

In ischemic stroke, the core infarction zone suffers irreversible damage due to cessation of cerebral blood flow, surrounded by the penumbra where cells are salvageable. This triggers a ischemic cascade involving excitotoxicity, oxidative stress, and inflammation. Hemorrhagic stroke involves direct tissue damage and compression from the hematoma, as well as secondary injury from released blood products. Research into these mechanisms is advanced at institutions like the National Institute of Neurological Disorders and Stroke.

Diagnosis

Diagnosis begins with a rapid clinical assessment, often using the FAST (stroke) acronym. Urgent neuroimaging is mandatory, with non-contrast CT scan being the first-line test to distinguish ischemic from hemorrhagic stroke. Magnetic resonance imaging, particularly diffusion-weighted imaging, is more sensitive for acute ischemia. Additional workup includes electrocardiography, carotid ultrasound, and tests to identify a cardioembolic source, guided by protocols from the American Stroke Association.

Prevention

Primary prevention focuses on managing vascular risk factors through blood pressure control with agents like lisinopril, lipid management with atorvastatin, and anticoagulation for atrial fibrillation with drugs like warfarin or apixaban. Lifestyle modifications, such as smoking cessation promoted by the World Health Organization and adherence to a Mediterranean diet, are cornerstone strategies. For patients with carotid artery stenosis, procedures like carotid endarterectomy or carotid stenting are considered.

Management

Acute ischemic stroke management centers on restoring blood flow via intravenous thrombolysis with alteplase within a strict time window, and/or mechanical thrombectomy for large vessel occlusions, as demonstrated in trials like MR CLEAN. Hemorrhagic stroke management involves blood pressure control, reversal of anticoagulants, and potentially surgical evacuation by a neurosurgeon. All patients receive care in specialized stroke units, which improve outcomes, and early rehabilitation with physical therapy and occupational therapy.

Prognosis

Prognosis varies widely; approximately one-third of patients recover fully, one-third are left with significant disability, and one-third do not survive. Outcomes are influenced by stroke severity, the affected brain region, and the speed of treatment. Long-term complications can include post-stroke depression, epilepsy, and dysphagia. Recovery is often monitored using scales like the modified Rankin Scale, and ongoing research into neuroplasticity and therapies like constraint-induced movement therapy aims to improve functional outcomes.

Category:Medical conditions Category:Neurological disorders