What is the recommended management for a patient with left-sided weakness and a possible acute to subacute infarct, as indicated by a subtle punctate focus of increased signal intensity on diffusion-weighted imaging within the left internal capsule on a MRI (Magnetic Resonance Imaging) of the brain without IV (Intravenous) contrast?

Management of Possible Acute Lacunar Infarct with Left-Sided Weakness

This patient requires immediate admission for comprehensive stroke workup and initiation of dual antiplatelet therapy, as the DWI hyperintensity in the left internal capsule—despite equivocal ADC findings—represents acute ischemic injury until proven otherwise, and DWI-positive lesions confer significantly higher risk for recurrent ischemic events. 1

Immediate Diagnostic Priorities

Confirm Acute Infarction Status

• The subtle DWI hyperintensity without definitive ADC correlation does not exclude acute infarction. DWI has 88-100% sensitivity and 95-100% specificity for detecting acute ischemia, and can identify lesions within minutes of symptom onset. 2
• Small punctate infarcts (3mm) in the internal capsule are classic lacunar strokes that frequently present with pure motor hemiparesis, precisely matching this patient's left-sided weakness. 1
• The absence of clear ADC hypointensity may reflect imaging timing or technical factors, but should not delay treatment given the clinical-radiographic correlation. 3

Urgent Vascular Imaging Required

Obtain CTA head and neck (or MRA if CTA contraindicated) immediately to identify treatable vascular lesions. 4, 1 This is critical because:

• Carotid stenosis ≥50% requires urgent revascularization consideration, with guidelines recommending vascular imaging within 24 hours of hospitalization due to high early recurrent stroke risk. 2
• Intracranial atherosclerotic disease in the middle cerebral artery or its perforators could explain the internal capsule infarct and requires specific secondary prevention strategies. 5
• Large-vessel occlusion substantially increases risk of early neurologic deterioration (18-fold increased odds) and poor functional outcome (7-fold increased odds), even in patients with mild or improving symptoms. 6

Comprehensive Cardiac Evaluation

Perform immediate cardiac workup including ECG, continuous telemetry monitoring, and transthoracic echocardiography. 1 This must include:

• Extended cardiac monitoring (30-day event monitor or implantable loop recorder) detects atrial fibrillation in 16.1% of cryptogenic stroke patients versus only 3.2% with standard monitoring. 4
• Detection of atrial fibrillation fundamentally changes management from antiplatelet to anticoagulation therapy. 4, 1

Acute Medical Management

Antiplatelet Therapy

Initiate dual antiplatelet therapy with aspirin and clopidogrel for 21 days, then transition to single antiplatelet agent. 1 This aggressive approach is warranted because:

• DWI-positive lesions indicate irreversible tissue injury requiring maximal secondary prevention. 1
• The presence of acute infarction on MRI reclassifies this event from TIA to completed stroke, mandating aggressive treatment. 1

Blood Pressure Management

Target blood pressure <130/80 mmHg using ACE inhibitors or ARBs as first-line agents. 4, 1 Evidence demonstrates improved survival and reduced vascular events with this approach. 4

Lipid Management

Initiate high-intensity statin therapy immediately, regardless of baseline LDL levels. 4, 1 This is a Class I recommendation for all ischemic stroke patients. 4

Critical Pitfalls to Avoid

Do Not Dismiss Equivocal DWI Findings

• Never attribute left-sided weakness to "chronic microvascular changes" when DWI shows any hyperintensity in a clinically relevant location. The scattered T2/FLAIR hyperintensities represent chronic small vessel disease, but the DWI abnormality indicates acute pathology. 2
• Approximately 10% of patients with mild or rapidly improving symptoms show early neurologic deterioration with infarct expansion within 48 hours, and 20% have poor outcomes at discharge. 6

Do Not Delay Vascular Imaging

Identifying carotid stenosis or intracranial atherosclerosis fundamentally changes management and can prevent devastating recurrent strokes. 4 The highest risk period for recurrent stroke is within the first 48-72 hours. 2

Do Not Rely on Standard Cardiac Monitoring Alone

Extended cardiac monitoring is required to adequately screen for paroxysmal atrial fibrillation in cryptogenic cases. 4 Standard 24-hour Holter monitoring misses the majority of paroxysmal atrial fibrillation. 4

Monitoring Protocol

Inpatient Surveillance

• Serial neurological assessments to detect clinical deterioration, particularly in the first 48 hours when risk of infarct expansion is highest. 6
• Repeat neuroimaging (CT or MRI) is indicated only if new symptoms develop or neurologic deterioration occurs—not for routine surveillance of stable infarcts. 2, 4

Follow-Up Strategy

• Schedule neurology follow-up within 2 weeks of discharge. 1
• Continue extended cardiac monitoring for minimum 30 days if no source is identified. 1
• Arrange carotid duplex ultrasound if CTA/MRA shows stenosis requiring quantification for revascularization decisions. 2, 4

Addressing the White Matter Changes

The periventricular and subcortical T2/FLAIR hyperintensities represent chronic small vessel disease (likely chronic microangiopathic ischemic changes given the clinical context), which increases future stroke risk but does not explain the acute presentation. 2 These findings reinforce the need for aggressive vascular risk factor modification. 4