• Clinical science

Overview of stroke


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.




Ischemic stroke Intracerebral hemorrhage Subarachnoid hemorrhage
Risk factors
Clinical features
  • Sudden onset of focal neurologic deficits
  • Headache, confusion, nausea
  • Sudden onset of focal neurologic deficits
  • Noncontrast head CT to rule out hemorrhage
  • MRI
  • Noncontrast head CT
  • MRI

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


Epidemiological data refers to the US, unless otherwise specified.



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


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
  • 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.

Brainstem syndromes

Pontine syndromes

Midbrain syndromes

Medullary syndromes

Clinical features of strokes affecting other regions

Location of lesion Clinical features [13][10]
Watershed border-zone
  • Watershed areas are most sensitive to profound hypoperfusion [22]
  • Anterior cerebral/middle cerebral cortical border zone: proximal upper and lower extremity weakness (man-in-the-barrel syndrome)
  • Posterior cerebral/middle cerebral cortical border zone: visual dysfunction


See aphasia.



Initial evaluation

Imaging [31][32]

  • 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

  • Initial: serum glucose
  • Additional evaluation
    • Complete blood count, electrolytes
    • Coagulation parameters (e.g., INR, PTT)
    • Urine drug screen for recreational substances (e.g., cocaine), blood alcohol level
    • Serum troponin

Laboratory studies should not delay imaging for patients with acute stroke. [32]


Differential diagnoses


The differential diagnoses listed here are not exhaustive.


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 [32]

Blood pressure management [32][38]

Nitrates should be avoided because they can increase intracranial pressure.

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



Medical complications [44]

Neurologic complications [45]


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