How do you localize a stroke from symptoms and signs?

Localization of Stroke from Symptoms and Signs

Stroke localization is primarily based on recognizing specific neurological deficits that correspond to vascular territories in the brain, with the FAST (Face, Arms, Speech, Time) assessment being the most validated and recommended tool for initial stroke recognition.

Key Stroke Symptoms and Signs for Localization

1. Anterior Circulation Strokes (Carotid Territory)

• Middle Cerebral Artery (MCA):

  • Contralateral hemiparesis (face and arm > leg)
  • Contralateral hemisensory loss
  • Aphasia (if dominant hemisphere, usually left)
  • Neglect (if non-dominant hemisphere, usually right)
  • Homonymous hemianopia

• Anterior Cerebral Artery (ACA):

  • Contralateral leg weakness > arm/face
  • Abulia (apathy, lack of initiative)
  • Urinary incontinence
  • Primitive reflexes

2. Posterior Circulation Strokes (Vertebrobasilar Territory)

• Vertebral Artery/Posterior Inferior Cerebellar Artery (PICA):

  • Dizziness, vertigo
  • Ataxia
  • Diplopia
  • Nausea/vomiting
  • Lateral medullary syndrome (Wallenberg): ipsilateral facial sensory loss, contralateral body sensory loss, ipsilateral Horner's syndrome, dysphagia, dysarthria 1

• Basilar Artery:

  • Bilateral motor deficits
  • Quadriparesis
  • Cranial nerve abnormalities
  • Altered consciousness
  • "Locked-in" syndrome (in complete basilar occlusion)

• Posterior Cerebral Artery (PCA):

  • Homonymous hemianopia
  • Visual hallucinations
  • Memory impairment
  • Sensory loss
  • Thalamic pain syndrome (if thalamic involvement)

FAST Assessment for Stroke Recognition

The FAST assessment is the most validated tool for initial stroke recognition and is recommended by multiple guidelines 2:

Assessment	Normal	Abnormal
Facial droop	Both sides move equally	One side doesn't move as well
Arm drift	Both arms move the same	One arm drifts down
Speech	Clear, appropriate speech	Slurred words, wrong words, or unable to speak
Time	Note time symptoms started	Call 911 immediately

Additional Stroke Symptoms Beyond FAST

While FAST captures the most common stroke symptoms, other important symptoms include:

• Sudden severe headache (especially in hemorrhagic stroke) 2
• Sudden trouble seeing in one or both eyes 2
• Sudden trouble walking, dizziness, loss of balance or coordination 2
• Numbness or tingling (reported in 44.5% of stroke cases) 3
• Gait disturbance (reported in 10.8% of cases) 3
• Vertigo (reported in 2.1% of cases) 3

Stroke Type Differentiation by Symptoms

Different stroke types may present with characteristic symptoms 3:

• Ischemic stroke (85% of strokes):

  • More likely to present with speech deficits (26.1%)
  • More likely to have sensory deficits (49.0%)

• Hemorrhagic stroke (15% of strokes):

  • More likely to present with headache (55.6% vs 22.4% in ischemic)
  • More likely to have convulsions/seizures (11.1% vs 3.2% in ischemic)
  • Less likely to have sensory deficits (19.4% vs 49.0% in ischemic)

Pediatric Stroke Considerations

Pediatric stroke can present differently than adult stroke 2:

• Focal signs: Hemiparesis, limb weakness, facial droop, altered sensation, visual/speech disturbance
• General signs: Altered mental status, seizure, headache, ataxia, vertigo/dizziness, nausea/vomiting

Adult stroke scores are not validated in the pediatric population and should not solely be used to identify stroke in children 2.

Clinical Pitfalls in Stroke Localization

• Stroke mimics: Conditions like migraine, seizure, hypoglycemia, and conversion disorder can mimic stroke symptoms
• Posterior circulation strokes: Often missed due to non-specific symptoms like dizziness and vertigo 1
• Lacunar strokes: May present with pure motor or pure sensory deficits without cortical signs
• Age-related differences: Elderly patients (≥65 years) are less likely to know stroke symptoms, potentially delaying recognition 4

Immediate Actions After Stroke Recognition

1. Activate emergency medical services immediately 2
2. Note the time of symptom onset (critical for treatment decisions) 2
3. Perform FAST assessment and communicate findings to EMS 2
4. Provide supplementary oxygen to hypoxemic stroke patients (oxygen saturation <94%) 2
5. Do not attempt to lower blood pressure in the prehospital setting unless systolic BP <90 mmHg 2

Telemedicine Considerations

When in-person neurological assessment is not immediately available, telemedicine evaluation using the NIH Stroke Scale (NIHSS) is recommended and has been shown to be comparable to bedside assessment 2.

Remember that early recognition and rapid activation of emergency services is critical for improving stroke outcomes. The FAST assessment remains the most validated tool for initial stroke recognition, though it may not capture all stroke presentations, particularly those in the posterior circulation 5.