Patient with imaging showing multifocal encephalomalacia in the right middle cerebral artery distribution and left basal ganglia/corona radiata – what are the expected neurological deficits, likely etiology, and recommended diagnostic work‑up and secondary stroke prevention management?

Neurological Deficits in Multifocal Encephalomalacia

Patients with multifocal encephalomalacia in the right MCA distribution will present with left-sided hemiparesis, left hemisensory loss, and left visual field defects, while left basal ganglia/corona radiata lesions typically cause right-sided motor and sensory deficits, often with dysarthria. 1, 2

Expected Neurological Deficits

Right MCA Territory Lesions

• Contralateral (left-sided) hemiparesis and hemisensory loss affecting the face, arm, and leg, with the arm and face typically more severely affected than the leg 2
• Left homonymous hemianopsia due to involvement of the optic radiations 1
• Left-sided neglect and visuospatial deficits if the non-dominant hemisphere is affected 3
• Incomplete neurological recovery is more common with MCA territory involvement compared to other vascular territories (50% complete recovery versus 83% for non-MCA strokes) 1

Left Basal Ganglia/Corona Radiata Lesions

• Right-sided motor and sensory deficits ranging from complete to partial sensorimotor symptoms 4
• Dysarthria occurs in approximately 25% of corona radiata infarcts, though it has limited localizing value 4
• Neuropsychological impairments including cognitive deficits, particularly when multiple lesions are present 4
• The clinical presentation can range from isolated motor or sensory symptoms to complete sensorimotor deficits depending on the extent of involvement 4

Likely Etiology

Primary Considerations

Cardioembolic stroke from infective endocarditis is the most critical diagnosis to exclude given the multifocal, bilateral distribution in multiple vascular territories. 1

• Multiple territory involvement (right MCA plus left basal ganglia) strongly suggests an embolic source rather than single-vessel atherosclerotic disease 1
• Infective endocarditis causes embolic strokes in 20-55% of cases, with the MCA territory affected in 40-55% of neurological complications 1
• Multifocal pattern with disseminated lesions in multiple territories is characteristic of cardioembolic disease 1

Other Etiologies to Consider

• Large-artery atherosclerotic disease accounts for 19% of corona radiata infarcts and can cause multiple emboli from unstable plaque 4
• Small-vessel disease with chronic hypertension causes 59% of corona radiata infarcts but typically presents with more symmetric, bilateral white matter disease and leukoaraiosis 4
• Atrial fibrillation or other cardiac sources of embolism account for 12% of corona radiata infarcts 4
• Arterial dissection, hypercoagulable states, or vasculitis should be considered in younger patients or those with atypical presentations 1

Recommended Diagnostic Work-Up

Immediate Neuroimaging

Brain MRI with diffusion-weighted imaging (DWI) is the preferred initial study to distinguish acute from chronic infarcts and characterize the full extent of injury. 1

• DWI and ADC maps will show restricted diffusion in acute infarcts (bright on DWI, dark on ADC) versus encephalomalacia from chronic infarcts 1
• FLAIR sequences help identify the age of lesions and associated white matter disease 1
• Gradient echo or susceptibility-weighted imaging is essential to detect hemorrhagic transformation, which occurs in 13-43% of ischemic strokes and is more common with large infarcts 1

Vascular Imaging

CT angiography (CTA) or MR angiography (MRA) of the head and neck should be performed urgently to identify large-vessel occlusion, stenosis, or mycotic aneurysms. 1

• Intracranial vascular imaging is mandatory to exclude mycotic aneurysms, which occur in 2-10% of infective endocarditis cases and are located in the MCA territory in 55-77% of cases 1
• Extracranial carotid and vertebral imaging identifies atherosclerotic disease requiring revascularization 1
• Digital subtraction angiography (DSA) should be considered if mycotic aneurysms are suspected, as it remains superior for detecting small (<3mm) aneurysms despite the risks 1

Cardiac Evaluation

Transthoracic echocardiography (TTE) followed by transesophageal echocardiography (TEE) if initial study is negative is essential when multifocal embolic strokes are identified. 1

• TEE is more sensitive than TTE for detecting vegetations, particularly on prosthetic valves 1
• Blood cultures (at least 3 sets from different sites) must be obtained before antibiotic initiation 1
• Electrocardiogram and continuous cardiac monitoring to detect atrial fibrillation 1

Laboratory Studies

• Complete blood count, metabolic panel, coagulation studies 1
• Fasting lipid panel and hemoglobin A1c for vascular risk stratification 1
• Hypercoagulability workup in younger patients or those without traditional risk factors 1
• Inflammatory markers (ESR, CRP) if vasculitis is suspected 1

Secondary Stroke Prevention Management

If Infective Endocarditis is Confirmed

Initiate appropriate antimicrobial therapy immediately after blood cultures are obtained, with regimen guided by culture results and sensitivities. 1

• Early cardiac surgery (within 2 weeks) offers better outcomes and survival with relatively low risk of neurological worsening in patients with ischemic stroke 1
• For minor ischemic strokes (<30% of a single lobe), surgery within 2 weeks has similar mortality to delayed surgery (47% versus 50%), with hemorrhagic conversion rates of 11% in week 1 and 10% in week 2 1
• Delay surgery for 3-4 weeks in patients with large parenchymal hemorrhage or severe neurological deficits with altered consciousness 1
• Serial neuroimaging is recommended to monitor for mycotic aneurysm growth or hemorrhagic transformation before cardiac surgery 1

If Atherosclerotic Disease is Identified

Dual antiplatelet therapy (aspirin plus clopidogrel) for 21 days followed by single antiplatelet agent for non-cardioembolic stroke. 1

• Carotid endarterectomy or stenting should be considered for symptomatic carotid stenosis ≥50% 1
• High-intensity statin therapy (atorvastatin 80mg or rosuvastatin 20-40mg daily) regardless of baseline LDL 1

If Cardioembolic (Non-IE) Source is Identified

Oral anticoagulation is indicated for atrial fibrillation or other high-risk cardiac sources. 1

• Delay anticoagulation for 4-14 days after large ischemic strokes to minimize hemorrhagic transformation risk 1
• Direct oral anticoagulants (DOACs) are preferred over warfarin for atrial fibrillation 1

Universal Secondary Prevention Measures

• Blood pressure control with target <130/80 mmHg after the acute phase, using ACE inhibitors or ARBs preferentially 1
• Diabetes management with target HbA1c <7% 1
• Smoking cessation and lifestyle modifications 1

Critical Pitfalls to Avoid

• Do not assume a single etiology: The bilateral, multifocal distribution mandates evaluation for cardioembolic sources even if atherosclerotic disease is present 1, 4
• Do not delay imaging for mycotic aneurysms: Any patient with suspected endocarditis and neurological symptoms requires urgent cerebrovascular imaging, as rupture can be catastrophic and unpredictable 1
• Do not use clinical features alone to distinguish hemorrhagic from ischemic stroke or to determine stroke mechanism—imaging is mandatory 1
• Do not start anticoagulation immediately in patients with large infarcts without repeat imaging to exclude hemorrhagic transformation 1
• Recognize that encephalomalacia indicates chronic injury: The presence of encephalomalacia suggests prior events, necessitating investigation for ongoing embolic sources or progressive vascular disease 5, 6