Lacunar infarcts are small ( to 15 mm in diameter) noncortical infarcts caused by occlusion of a single penetrating branch of a large cerebral artery . Lacunar strokes are noncortical infarcts and are characterized by the absence of cortical signs such as aphasia hemianopsia, agnosia, and apraxia. Clinical Differentiation: Cortical vs. Subcortical Strokes. Left fronto-parietal cortical stroke. Cortical. Subcortical Lacunar Stroke (internal capsule on the left).
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Stroke is lwcunar acute neurological condition due to a focal cerebrovascular event, which may either be vascular occlusion ischemic stroke or rupture hemorrhagic stroke. Hemorrhagic stroke is further classified into intracerebral hemorrhageif the bleeding occurs within the cerebral parenchymaand subarachnoid hemorrhageif the bleeding occurs in the subarachnoid space.
Hypertensioncoagulation disordersand cardiac diseases are common causes of both ischemic and hemorrhagic stroke. Stroke is characterized by the sudden onset of neurologic deficits, as well as nonspecific symptoms headachenausea, altered mental status.
Distinguishing between ischemic stroke and hemorrhagic stroke is not usually possible based on clinical features. Subarachnoid hemorrhageon the other hand, has a distinct clinical presentation. A detailed evaluation of the focal neurological deficits may provide a clue as to the affected cerebral vessel or region. Hemiparesisaphasiaand hemianopsia are common. A noncontrast head CT is the most important diagnostic procedure, serving primarily to confirm or rule out intracranial hemorrhage.
Further neurovascular imaging may be required in order to decide on treatment options. If an occluded vessel is responsible for the stroke, recanalization should be attempted as quickly as possible to salvage the greatest possible amount of tissue.
The Radiology Assistant : Brain Ischemia – Vascular territories
The management of hemorrhagic stroke involves supportive measures and neurosurgery. Long-term management focuses on the elimination of risk factors. Epidemiological data refers to the US, unless otherwise specified. Arterial hypertension is the strongest single predisposing factor for the development of both ischemic and hemorrhagic stroke!
Age is the most important nonmodifiable risk factor! Arterial hypertension is the most important modifiable risk factor! Hemorrhagic stroke is due to intracerebral hemorrhage or subarachnoid hemorrhage.
Both forms of lacunae can be traumatic or nontraumatic spontaneous. Traumatic forms are discussed separately in traumatic brain injury. Middle cerebral artery MCA most commonly affected vessel overall. Lacunar strokes are noncortical infarcts and are characterized by the absence of cortical signs such as aphasia hemianopsiaagnosiaand apraxia.
A watershed infarct is a border-zone infarct ; in the region between the territory of two major arteries that supply the brain i. TIA is primarily a clinical diagnosis. However, patients with suspected TIA are at an increased risk of ischemic stroke and therefore also require immediate diagnostic work-up, including neuroimaging!
Depending on the severity of ischemiabrain tissue responds to ischemia in two major ways: Nitrates should be avoided since they may increase the intracranial pressure! Reperfusion therapy should not be delayed — time is everything! However, intracranial hemorrhage is a contraindication for reperfusion therapy and must always be ruled out first! Patients with signs of brain herniation should be operated on immediately!
All patients with a history of ischemic stroke or TIA require lavunar prophylaxiswhich should be initiated immediately within one day of lscunar ischemic lacunzr to reduce the risk of reccurent stroke. Clinical science Stroke is an acute neurological condition due to a focal cerebrovascular event, which may either be vascular occlusion ischemic stroke or rupture hemorrhagic stroke. Stroke is the fifth leading cause of death and the leading cause of disability in the US.
Etiology Large artery atherosclerosis: Risk factors Nonmodifiable Age Sex Ethnicity Family history of cardiovascular or cerebrovascular disease Genetic disorders e.
Symptoms depend on the location of the stroke see the sections below Sudden onset of focal neurologic deficits and nonspecific symptoms impaired consciousness, nausea, vomiting, headacheand, less commonly, seizures Transient ischemic attack TIA: Contralateral homonymous hemianopia with macular sparing Contralateral hemisensory loss: Lacunar stroke Lacunar strokes are noncortical infarcts and are characterized by the absence of cortical signs such as aphasia hemianopsiaagnosiaand lacunxr.
Signs of systemic hypoperfusion: A lacunarr cause of locked-in syndrome. Initial evaluation Clinical assessment and history Identify risk factors for ischemic or hemorrhagic stroke. Signs of the affected vessel or region Signs of large vessel occlusion e.
Laboratory studies Complete blood count Coagulation parameters e. Neuroimaging Noncontrast cranial CT gold standard and most important initial imaging: Highest specificity and sensitivity for most cerebrovascular pathologies including stenosis, dissectionsvasculitis lacumar, and fibromuscular dysplasia Transcranial doppler sonography: Patterns of necrosis in ischemic stroke Depending on the severity of ischemiabrain tissue responds to ischemia in two major ways: Seizures Metabolic disorders hyponatremiahypoglycemia Migraine aura Systemic infection Brain tumor Psychiatric conversion disorders Peripheral vestibulopathy Traumatic intracranial hemorrhage References: Severe cases require decompression surgery Maintain sufficient cerebral perfusion Antihypertensive treatment e.
Patients who undergo thrombolytic therapy: Seizures should be treated pharmacologically Cardiac monitoring for at least 24 hours Nitrates should ,acunar avoided since they may increase the intracranial pressure!
Additional measures For zvc stroke: Early treatment of infections with antibioticsbut prophylaxis is not generally recommended References: Reperfusion therapy Reperfusion therapy should not be delayed — time is everything! Antiplatelet therapy Indicated in all ischemic stroke patients Contraindicated for 24 hours after thrombolytic therapy Drug of choice: Early rehabilitation physiotherapyoccupational and speech therapy and mobilization References: Intracerebral hemorrhage Reverse anticoagulation Craniotomy and clot evacuation Indications Signs of brain herniation e.
Subarachnoid hemorrhage Reverse anticoagulation Prevent vasospasm ; can cause ischemic stroke with IV calcium channel blocker i. Antihypertensive treatment Antiplatelet drugs e.
Brain Ischemia – Vascular territories
Medical complications Cardiac dysfunction arrhythmiasmyocardial infarction Aspiration pneumonia Deep vein thrombosis and pulmonary embolism Urinary tract infections Post-stroke bone fractures Depression Neurologic complications Elevated intracranial pressure and brain herniation Cushing triad Seizures Persistent neurologic deficits hemiparesisaphasia In ischemic stroke: Hemorrhagic transformation may occur.
Hemorrhagic stroke has a worse prognosis than ischemic stroke. Persistent neurologic deficits and disability are common in survivors. Prepare and succeed on your medical exams. Find hundreds of Learning Cards covering all clinical subjects Practice answering thousands of USMLE-formatted multiple choice questions in the Qbank Explore concepts in depth with interactive images, videos and charts Fill knowledge gaps with the help of supportive features and an analysis of your progress.
Lacunar syndromes see Lacunar stroke for details. Vertebrobasilar insufficiency Ipsilateral cranial nerve deficits Vertigodrop attackstinnitushiccupsdysarthriadysphagia Visual deficits Gait ataxia Crossed paresthesias Crossed hemiplegia Brainstem syndromes Wallenberg syndrome: Ipsilateral amaurosis fugax Numerous contralateral symptoms possible e. Horner’s syndrome Paralysis of the hypoglossal nerve Signs of middle cerebral artery infarction.
Wallenberg syndrome Neck pain Signs of posterior cerebral artery infarction see carotid and vertebral artery dissection. Contralateral hemiparesis of the face, armand leg.
Thalamusthe posterior limb of the internal capsulepontine tegmentumor corona radiata. Contralateral numbness and paresthesia of the face, armand leg. Hemiparesis and ipsilateral sensory impairment. Corona radiata or the posterior limb of the internal capsule.
Cortical vs Subcortical
Ipsilateral impaired coordination e. Base of the pons. Dysarthrialaucnarcontralateral facial and hand weakness. Contralateral involuntary large and fierce flinging movements of the arm or leg. Reactive gliosis astrocytes Vascular proliferation.