How do I diagnose a recurrent cerebrovascular accident (stroke) in a patient with a history of prior stroke and vascular risk factors?

Diagnosing Recurrent Cerebrovascular Accident (CVA)

In a patient with prior stroke presenting with new neurological symptoms, immediately perform non-contrast CT or MRI brain to confirm acute ischemic cerebral vascular disease, as brain imaging is required to guide acute intervention and distinguish recurrent stroke from hemorrhagic transformation or stroke mimics. 1

Immediate Clinical Assessment

Time-Critical History

• Establish the exact time the patient was last known to be at neurological baseline - this is the single most critical piece of information for determining treatment eligibility 2
• Document whether symptoms are transient, fluctuating, or persistent 1
• Patients presenting within 48 hours with unilateral weakness (face, arm, leg) or speech disturbance/aphasia are at highest risk for recurrent stroke 1

Focused Neurological Examination

• Perform the NIH Stroke Scale (NIHSS) to measure stroke severity, provide prognostic information, and influence acute treatment decisions 2
• Assess level of consciousness, focal neurological deficits, cranial nerves, motor movements, reflexes, and Babinski signs 2
• Measure blood pressure immediately - hypertension is common in acute ischemic stroke 2

Essential Diagnostic Testing

Neuroimaging (First Priority)

Brain imaging must be completed within 24 hours, ideally immediately 1, 3:

• Non-contrast CT head is the most important initial test at most institutions to exclude hemorrhage and confirm ischemic disease 1, 3
• MRI brain (DWI/FLAIR sequences) is more sensitive than CT for detecting acute ischemic stroke, particularly for small infarcts and posterior circulation strokes 1, 4
• If initial imaging does not demonstrate symptomatic cerebral infarct, follow-up MRI is reasonable to confirm diagnosis and predict risk of early stroke 1

Critical timing: CT should be completed within 25 minutes of arrival with interpretation within 45 minutes 3

Vascular Imaging (Concurrent with Brain Imaging)

Noninvasive cervical and intracranial vascular imaging should be performed urgently within 24 hours 1:

• CTA from aortic arch to vertex or MRA to screen for arterial stenosis, occlusions, and identify stroke mechanism 1, 3
• For anterior circulation symptoms with candidacy for revascularization, carotid imaging with ultrasonography, CTA, or MRA is recommended 1
• Intracranial large artery imaging can identify atherosclerotic disease, dissection, or moyamoya 1

Laboratory Testing (Do Not Delay Imaging)

Complete the following tests within 48 hours, but do not delay neuroimaging 1, 3:

• Complete blood count, prothrombin time, partial thromboplastin time 1
• Glucose, HbA1c, creatinine 1
• Fasting or non-fasting lipid profile 1
• Troponin and 12-lead ECG (high incidence of concurrent cardiac disease) 2, 3

Important caveat: For patients on warfarin, INR is required before thrombolytic administration, but otherwise do not wait for laboratory results to initiate imaging or treatment 1, 3

Cardiac Evaluation

Echocardiography is reasonable in cryptogenic stroke to evaluate for cardiac sources of embolism 1:

• Transthoracic echocardiography (TTE) with or without contrast as initial test 1
• Transesophageal echocardiography (TEE), cardiac CT, or cardiac MRI might be reasonable for embolic stroke of undetermined source (ESUS) 1
• Long-term rhythm monitoring (mobile cardiac outpatient telemetry or implantable loop recorder) is reasonable to detect intermittent atrial fibrillation in cryptogenic stroke 1

Distinguishing Recurrent Stroke from Mimics

Common Stroke Mimics to Exclude

Rapidly rule out conditions that can mimic stroke 2, 5:

• Post-seizure state (Todd's paralysis) - check for seizure history
• Hypoglycemia - immediate glucose testing
• Brain neoplasm - contrast imaging if clinical suspicion
• Migraine with aura - detailed headache history
• Psychogenic disorders - inconsistent examination findings

Key principle: Suspect stroke in any patient with abrupt onset of neurological symptoms, but perform systematic neurological examination to identify the true nature of the problem 5

Risk Stratification for Recurrent Events

Highest Risk Features (Requires Emergency Department Evaluation)

Patients with these features have 3-6% stroke risk in first 1-4 weeks and up to 24% concurrent stroke on MRI 1:

• Symptom onset within 48 hours 1
• Unilateral motor weakness or speech disturbance 1
• Large artery atherosclerosis (LAA) or cardioembolic (CE) stroke subtypes have highest recurrence rates 6

Silent Brain Infarction

Up to 19-25% of patients with acute retinal or cerebral artery occlusion have silent brain infarction on DWI-MRI 1:

• These silent infarctions carry high risk for future stroke 1
• Prompt referral to stroke center is warranted even without overt symptoms 1

Additional Testing for Cryptogenic Stroke

When stroke mechanism remains unclear after initial workup, consider 1:

• Tests for hypercoagulable states (inherited or acquired)
• Infections causing CNS vasculitis (HIV, syphilis)
• Drug screening (cocaine, amphetamines)
• Markers of systemic inflammation
• Genetic tests for inherited stroke-associated diseases

Critical Pitfalls to Avoid

• Do not delay thrombolytic therapy waiting for laboratory results unless clinical suspicion of bleeding abnormality, thrombocytopenia, or recent heparin/warfarin use 2
• Do not aggressively treat elevated blood pressure unless diastolic BP >120 mmHg or systolic BP >220 mmHg in non-thrombolytic candidates 2
• Do not assume small vessel occlusion (SVO) stroke has low recurrence risk - these patients often have recurrent strokes of different subtypes and require extensive workup 6
• Do not rely solely on CT in the first 24 hours - up to 24% of patients with retinal artery occlusion have concurrent cerebrovascular accident detected only on DWI-MRI, not CT 1

Cardiovascular Risk Assessment

All patients require comprehensive cardiovascular risk evaluation 1:

• Assess for coronary heart disease history (myocardial infarction, angina, arrhythmias, heart failure) 1
• Calculate 10-year CHD risk using Framingham algorithms 1
• Patients with high cardiovascular risk profiles (≥20% 10-year CHD risk) or significant carotid disease should be considered for noninvasive cardiac testing 1