What is the appropriate clinical workup for a patient presenting with left-sided weakness?

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Last updated: March 17, 2026 • View editorial policy

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Clinical Workup for Left-Sided Weakness

For a patient presenting with left-sided weakness, immediately obtain CT head without contrast to exclude hemorrhagic stroke, followed by rapid vascular imaging with CTA head and neck to identify large-vessel occlusion and guide potential reperfusion therapy. 1, 2

Immediate Imaging (Within 30 Minutes of Arrival)

Primary Brain Imaging

  • CT head without IV contrast is the most practical first-line test to rapidly exclude intracranial hemorrhage and identify early ischemic changes 1, 3
  • MRI brain without contrast provides superior detection of acute ischemia (approaching 100% sensitivity vs <60% for CT), particularly for small cortical, deep, and posterior-fossa infarcts 2, 3
    • Diffusion-weighted imaging (DWI) is the most sensitive and specific sequence for detecting acute cerebral ischemia within minutes of symptom onset 2
    • Gradient-recalled echo (GRE) or susceptibility-weighted imaging (SWI) reliably excludes intracranial hemorrhage with sensitivity equal to or better than CT 2
    • FLAIR imaging identifies subacute ischemia and helps exclude stroke mimics 2
  • Complete brain imaging must be finished within 30 minutes of emergency department arrival 2, 3

Rapid Vascular Assessment

  • CTA head and neck is the preferred rapid-assessment modality to identify arterial occlusion, dissection, large-vessel atherosclerosis, and guide endovascular therapy decisions 1, 3
  • MRA head and neck (time-of-flight or contrast-enhanced) is an alternative when MRI is the primary modality, essential for identifying large-vessel occlusion and clarifying stroke mechanism 2
  • Vascular imaging should be obtained during initial evaluation but must not delay intravenous thrombolysis when patients are within the therapeutic window 2, 3

Cardiac Evaluation (Immediate and Continuous)

  • 12-lead ECG performed immediately to screen for atrial fibrillation, atrial flutter, and acute myocardial infarction 3
  • Continuous cardiac rhythm monitoring for at least 24-72 hours to capture intermittent arrhythmias 3
  • Transesophageal echocardiography is reasonable in cryptogenic stroke to identify paradoxical embolism pathways (patent foramen ovale) and aortic sources of emboli 3
  • Long-term rhythm monitoring using mobile cardiac outpatient telemetry or implantable loop recorder for cryptogenic stroke to detect intermittent atrial fibrillation 3

Laboratory Evaluation (Baseline)

  • Complete blood count, prothrombin time, partial thromboplastin time to assess bleeding risk and coagulation status 3
  • Glucose and HbA1c to identify hyperglycemia as a stroke mimic and assess diabetes control 3
  • Creatinine to evaluate renal function before contrast administration 3
  • Fasting or non-fasting lipid profile for cardiovascular risk assessment 3
  • HIV and syphilis serologies in appropriate clinical contexts 3

Time-Dependent Advanced Imaging

For Patients Presenting 6-24 Hours After Last Known Well

  • MR perfusion imaging or arterial spin labeling to delineate salvageable tissue via core-perfusion mismatch and guide extended-window reperfusion therapy 2
  • DWI-FLAIR mismatch can select patients who may benefit from intravenous thrombolysis beyond the conventional 4.5-hour window 2

Critical Pitfalls to Avoid

  • Do not delay emergency reperfusion treatment to obtain multimodal imaging; imaging should not postpone therapy when patients are within the 3-hour therapeutic window 3
  • Do not routinely obtain chest radiography unless there is specific clinical suspicion of pulmonary, cardiac, or vascular disease 3
  • Do not administer prophylactic anticonvulsant drugs routinely to patients who have not experienced seizures 3
  • Imaging acquisition must be completed efficiently—a standard multimodal MRI protocol (DWI, FLAIR, GRE/SWI, MRA, perfusion) can be completed in approximately 10 minutes 2

Algorithmic Approach Based on Presentation Time

Within 0-4.5 Hours (IV Thrombolysis Window)

  • Minimum required sequences: DWI, FLAIR, GRE/SWI to exclude hemorrhage and assess ischemic extent 2
  • Add MRA if endovascular therapy is available and it does not postpone treatment 2

Endovascular Therapy Candidates (0-24 Hours)

  • Complete protocol including head and neck MRA during initial assessment 2
  • Perfusion imaging when presentation is beyond 6 hours from onset to identify viable penumbra 2

TIA or Non-Thrombolysis Candidates

  • Multimodal MRI is preferred over CT, focusing on DWI (positive in ~40% of TIAs), vascular imaging (MRA or CTA), and determination of stroke mechanism 2

Additional Vascular Assessment

  • Carotid duplex ultrasonography can screen for stenosis when anterior-circulation symptoms are present 3
  • Transcranial Doppler ultrasonography detects intracranial vessel abnormalities and can be employed for embolus detection 3
  • Imaging of extracranial vertebrobasilar arterial system with MRA or CTA helps identify dissection and other vasculopathies 3

References

2
Guideline

Acute Stroke MRI Protocol Recommendations

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

3
Guideline

Guideline Recommendations for Diagnostic Workup of Stroke in Young Adults

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.