What are the immediate investigation steps for a chronic smoker with Type 2 Diabetes presenting with acute ischemic stroke?

Immediate Investigation for Acute Ischemic Stroke in a Chronic Smoker with Type 2 Diabetes

Perform non-contrast CT brain imaging immediately upon arrival (within 30 minutes) to exclude hemorrhage, followed by CT angiography from aortic arch to vertex to assess both extracranial and intracranial circulation, while simultaneously obtaining essential laboratory tests that should not delay imaging or treatment decisions. 1, 2

Immediate Brain Imaging (Priority #1)

• Non-contrast CT or MRI must be completed within 30 minutes of hospital arrival to differentiate ischemic from hemorrhagic stroke and assess extent of ischemic changes 1, 2
• CT angiography (CTA) from aortic arch to vertex should be performed concurrently with the initial brain CT to visualize extracranial carotid arteries, intracranial circulation, posterior circulation, and aortic arch in a single imaging session 1, 2, 3
• CT is preferred initially due to faster acquisition time and wider availability, though MRI with diffusion-weighted imaging provides superior sensitivity for early ischemic changes if available 24/7 and can be completed rapidly 2

Simultaneous Laboratory Investigations (Do Not Delay Imaging)

Essential blood work to obtain immediately: 1, 2

• Complete blood count with platelet count - to assess for thrombocytopenia or bleeding risk
• Blood glucose (capillary and serum) - critical in diabetic patients as hyperglycemia worsens stroke outcomes and approximately 20% of stroke patients have undiagnosed diabetes 1
• Serum electrolytes and renal function (creatinine, eGFR) - essential for treatment decisions
• Coagulation studies (PT/INR, aPTT) - mandatory before thrombolytic therapy consideration 1
• Cardiac biomarkers (troponin) - to detect concurrent myocardial infarction, which occurs in approximately 3% of acute stroke patients 1

Important caveat: These laboratory results are desirable before administering thrombolytic therapy, but fibrinolytic treatment should NOT be delayed while awaiting results unless there is clinical suspicion of bleeding abnormality, thrombocytopenia, or the patient has received anticoagulants 1

Immediate Cardiac Evaluation

• 12-lead ECG must be performed rapidly after arrival to identify atrial fibrillation (a major embolic source), acute myocardial infarction, or other cardiac abnormalities 1, 2
• ECG should not delay acute stroke treatment but is essential for determining stroke etiology and guiding secondary prevention 1

Clinical Assessment (Concurrent with Imaging)

• Document precise time of symptom onset (or last known well time) - this is the single most critical piece of information for determining treatment eligibility 2, 3, 4
• Assess stroke severity using NIHSS (National Institutes of Health Stroke Scale) - provides prognostic information and influences acute treatment decisions 1, 2
• Measure oxygen saturation and assess airway, breathing, circulation 1, 3
• Obtain vital signs including blood pressure (must be <185/110 mmHg before thrombolysis), heart rate, temperature 1, 3

Additional Investigations Within 24 Hours (Not Immediate)

• Vascular imaging of carotid arteries (if not done with initial CTA) using duplex ultrasound or MR angiography to identify carotid stenosis requiring revascularization 1
• Extended cardiac monitoring (>24 hours) to detect paroxysmal atrial fibrillation in patients with suspected embolic stroke 2
• Echocardiography (transthoracic or transesophageal) for suspected cardiac source of embolism, particularly relevant given diabetes increases risk of cardioembolism 1, 2
• HbA1c testing to assess glycemic control - higher HbA1c is independently associated with increased intracranial plaque enhancement and worse outcomes in diabetic stroke patients 1, 5

Special Considerations for Diabetic Smokers

• This patient population has increased intracranial plaque burden and higher risk of small arterial occlusions compared to non-diabetic patients 5, 6
• Poorly controlled diabetes (higher HbA1c) is independently associated with stronger plaque enhancement and potentially more vulnerable atherosclerotic lesions 5
• The combination of smoking and diabetes creates additive effects on neurovascular unit transporters, potentially worsening stroke prognosis 7
• Triglyceride levels should be assessed as part of lipid panel, since elevated triglyceride-glucose index predicts stroke recurrence and mortality in diabetic stroke patients 8

Tests That Should NOT Delay Treatment

• Chest radiography is optional unless there is clinical suspicion of pulmonary disease, cardiac disease, or aortic dissection - routine chest X-ray alters management in only 3.8% of cases 1
• Hepatic function tests, toxicology screen, blood alcohol level are selective tests based on clinical suspicion 1
• Lumbar puncture only if subarachnoid hemorrhage is suspected and CT is negative for blood 1

Critical Timing Benchmarks

• Door-to-imaging time: ≤25 minutes 2
• Door-to-needle time (if thrombolysis indicated): ≤60 minutes, ideally ≤30 minutes 1, 3
• Laboratory results availability: within 20 minutes of blood sampling for thrombolysis candidates 1