• Clinical science

Overview of stroke

Summary

A stroke is an acute neurologic condition resulting from a disruption in cerebral perfusion, either due to ischemia (ischemic strokes) or hemorrhage (hemorrhagic strokes). Hemorrhagic strokes are further classified as intracerebral or subarachnoid. Systemic hypertension and other cardiovascular diseases are common risk factors for both ischemic and hemorrhagic strokes. Clinically, strokes are characterized by the acute onset of focal neurologic deficits, including hemiparesis, paresthesias, and hemianopsia. The pattern of clinical features is dictated by the affected vessel. Distinguishing between ischemic and hemorrhagic strokes based on physical examination is difficult and requires initial evaluation with a noncontrast head CT. Further neurovascular imaging may be required before deciding on treatment options. In ischemic strokes, immediate revascularization of the affected vessel is vital to preserve brain tissue and prevent further damage. Hemorrhagic strokes are treated with supportive measures and neurosurgical evacuation of blood. Long-term management of all types of stroke focuses on the management of modifiable risk factors (i.e., hypertension and atherosclerosis).

For more information, see ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage.

Definition

References:[2][3][4]

Overview

Ischemic stroke Intracerebral hemorrhage Subarachnoid hemorrhage
Epidemiology
Etiology
Risk factors
Clinical features
  • Sudden onset of focal neurologic deficits
  • Headache, confusion, nausea
  • Sudden onset of focal neurologic deficits
Diagnosis
  • Noncontrast head CT to rule out hemorrhage
  • MRI
  • CTA/MRA
  • Noncontrast head CT
  • MRI
  • CTA/MRA
Treatment
Pathology

For both ischemic and hemorrhagic strokes, age is the most important nonmodifiable risk factor and arterial hypertension is the most important modifiable risk factor!

Epidemiology

Epidemiological data refers to the US, unless otherwise specified.

Etiology

  1. Ischemic stroke (85%)
  2. Hemorrhagic stroke (∼ 15%)

References:[6][7]

Stroke symptoms by affected vessel

Affected vessel Clinical features [8][9][10]

Middle cerebral artery (MCA) (most commonly affected vessel)

Anterior cerebral artery (ACA)
Posterior cerebral artery (PCA)
Posterior inferior cerebellar artery
Anterior inferior cerebellar artery
Lenticulostriate arteries (penetrating arteries)
Basilar artery
Extracranial arteries Internal carotid artery
Common carotid artery
Vertebral artery
Anterior spinal artery

References:[14][15][10][16][11][17][18][19][20]

Stroke symptoms by affected region

Lacunar syndromes [21]

Lacunar stroke type Location Clinical features
Pure motor stroke
Pure sensory stroke
  • Contralateral numbness and paresthesia of the face, arm, and leg
Sensorimotor stroke
Ataxic hemiparesis
  • Ipsilateral weakness with impaired coordination (e.g., ataxia, gait instability)
Dysarthria-clumsy hand syndrome
  • Contralateral facial and hand weakness with dysarthria
Hemiballismus
  • Contralateral, involuntary, large flinging movements of the arm or leg

Infarction of the posterior limb of the internal capsule is the most common type of lacunar stroke and may manifest clinically with pure motor stroke, pure sensory stroke (rare), sensorimotor stroke, dysarthria-clumsy hand syndrome, and/or ataxic hemiparesis.

Pontine syndromes

Clinical features of strokes affecting other regions

Location of lesion Clinical features [13][10]
Putamen
Cerebellum
Thalamus
Cortex

Aphasia

See aphasia.

References:[10][22][19][23][24][25][26][27][28][29]

Diagnostics

Initial evaluation

Imaging [30][31]

  • Approach: noncontrast head CT to evaluate for acute hemorrhagediffusion-weighted MRI to detect acute ischemia → consider further neurovascular imaging depending on the type of stroke
  • Noncontrast head CT (first-line imaging)
    • Allows for detection of acute hemorrhage but cannot be used to reliably identify early ischemia
    • Indicated in all patients suspected of having an acute stroke to rule out intracranial hemorrhage before administering thrombolytic therapy
  • Diffusion-weighted MRI
    • Allows identification of ischemia earlier than a CT (within 3–30 minutes after onset)
    • Allows detection of hyperacute hemorrhage
    • Evaluates reversibility of ischemic injury
  • See ischemic stroke, subarachnoid hemorrhage, and intracerebral hemorrhage for specific imaging findings and other modalities.

Laboratory evaluation

Laboratory studies should not delay imaging for patients with acute stroke. [31]


References:[32][33][34][8][35][30]

Differential diagnoses

References:[34][36]

The differential diagnoses listed here are not exhaustive.

Treatment

If symptoms of a suspected ischemic stroke began less than 4.5 hours prior to presentation and there are no signs of intracranial bleeding, begin reperfusion therapy immediately!

Stabilization and monitoring [31]

Blood pressure management [31][37]

Nitrates should be avoided because they can increase intracranial pressure.

See ischemic stroke, subarachnoid hemorrhage, and intracerebral hemorrhage for specific management.

References:[38][37][34][35][39][40][41][42]

Complications

Medical complications [43]

Neurologic complications [44]

References:[47][48][44][43]

We list the most important complications. The selection is not exhaustive.