What is the initial treatment for a patient presenting with symptoms suggestive of ischemic stroke?

Differential Diagnosis for Ischemic Stroke

The primary goal when evaluating a patient with suspected ischemic stroke is to immediately confirm the diagnosis is stroke and not another condition, particularly intracranial hemorrhage, while simultaneously determining eligibility for acute thrombolytic therapy. 1

Immediate Diagnostic Priorities

The differential diagnosis must be rapidly narrowed through three critical determinations 1:

1. Confirm the symptoms are due to ischemic stroke versus other neurological or systemic illness
2. Exclude intracranial hemorrhage (occurs in 15% of all strokes) 1
3. Rule out stroke mimics that present with focal neurological deficits

Key Stroke Mimics to Exclude

Intracranial Hemorrhage

• Brain imaging (CT or MRI) must be completed immediately to definitively exclude parenchymal hemorrhage before any reperfusion therapy 1, 2
• Non-contrast CT accurately identifies most cases of intracranial hemorrhage and helps discriminate non-vascular causes 1

Metabolic and Systemic Disorders

• Hypoglycemia and hyperglycemia can present with focal neurological deficits mimicking stroke 2
• Electrolyte abnormalities (particularly hyponatremia) may cause stroke-like symptoms 2
• Initial blood work including complete blood count, electrolytes, glucose, coagulation studies (INR, aPTT), and renal function must be obtained 2
• These metabolic abnormalities require rectification as a time-sensitive intervention (21.5% of in-hospital stroke alerts) 3

Seizures and Post-Ictal States

• Todd's paralysis (post-ictal weakness) can mimic acute stroke 1
• New-onset seizures should be treated with short-acting medications if not self-limiting 2
• Temperature should be monitored every 4 hours for the first 48 hours, with fever reduction if temperature exceeds 37.5°C 2

Structural Brain Lesions

• Brain tumors can present with acute focal deficits 1
• Subdural hematoma may cause stroke-like symptoms, particularly in elderly or anticoagulated patients 1
• MRI with contrast may be needed in the subacute phase to assess for underlying neoplastic masses 1

Infectious and Inflammatory Conditions

• Infectious endocarditis should be considered, particularly when C-reactive protein ≥10 mg/L (OR 22 for endocarditis) 4
• Septic emboli can cause multiple focal deficits 1
• Encephalitis may present with focal neurological signs 1

Vascular Mimics

• Aortic dissection must be excluded if there are specific intrathoracic concerns before administering thrombolytics 1
• Arterial dissection (particularly vertebral or carotid) can present similarly to ischemic stroke 4
• Cerebral venous thrombosis requires specific vascular imaging to diagnose 4

Functional and Psychiatric Disorders

• Nonfocal neurological deficits are commonly encountered (46.2% of in-hospital stroke alerts) and often represent non-cerebrovascular disorders 3
• Conversion disorder can mimic stroke symptoms 3

Critical Diagnostic Algorithm

Within Minutes of Arrival 2, 5:

1. Assess ABCs (airway, breathing, circulation) immediately
2. Establish time of symptom onset (last known normal) - critical for treatment eligibility
3. Obtain vital signs: heart rate/rhythm, blood pressure, temperature, oxygen saturation
4. Perform NIHSS to assess stroke severity
5. Complete brain imaging immediately (CT or MRI) - target within 45 minutes of ED arrival 1

Concurrent Diagnostic Studies 2:

• Blood work: CBC, electrolytes, coagulation studies, renal function, glucose, troponin
• 12-lead ECG to detect atrial fibrillation or acute myocardial infarction
• CT angiography from aortic arch to vertex when possible at time of initial brain CT 2

Additional Considerations for Young Patients (<50 years) 4:

• Toxicology screening for cocaine and drugs of abuse (cocaine increases stroke risk >6-fold)
• Hypercoagulable state testing (higher yield in younger populations)
• Transthoracic and transesophageal echocardiography (cardiac disorders account for 31% of pediatric strokes)
• MRI with vessel wall imaging to detect arteriopathies (53% of pediatric strokes)

Common Pitfalls

• Do not delay thrombolytic therapy for chest radiography unless specific intrathoracic concerns exist 1
• Do not wait for additional imaging before administering IV tPA if patient meets criteria and CT excludes hemorrhage 1
• Recognize that 51.2% of stroke alerts are non-cerebrovascular disorders, requiring alternative time-sensitive interventions 3
• Drug effects requiring reversal account for 11% of in-hospital stroke presentations and must be addressed urgently 3