What is the clinical presentation of an acute infarct in the left corona radiata?

Clinical Presentation of Acute Left Corona Radiata Infarct

Acute infarction of the left corona radiata typically presents with contralateral (right-sided) motor weakness, often affecting the upper limb more than the lower limb, frequently accompanied by dysarthria and mild sensory disturbances. 1

Motor Deficits

The hallmark presentation involves contralateral hemiparesis or hemiplegia, with several characteristic patterns:

• Upper limb predominance is the most common pattern, with motor paralysis usually occurring more severely in the upper extremities 2
• Pure motor hemiplegia occurs in approximately 45% of patients, presenting as weakness without sensory or cortical signs 2
• Monoplegia can occur in 13% of cases, with the specific location within the corona radiata determining whether upper or lower limb is affected—anterior lesions cause upper limb monoplegia, while posterior lesions cause lower limb monoplegia 2
• Facial weakness is present in approximately 55% of patients 2

Speech and Bulbar Symptoms

• Dysarthria occurs in approximately 58-60% of patients and represents a key clinical feature, though it has no specific localizing value within the corona radiata 1, 2
• The dysarthria is typically present alongside motor deficits rather than in isolation 1

Sensory Disturbances

• Sensory abnormalities are reported in approximately 47% of patients, though these are usually mild 2
• Sensory symptoms typically manifest as subjective feelings of abnormality localized to the affected limbs rather than dense sensory loss 2
• When present, sensory deficits combined with motor weakness create a sensorimotor syndrome pattern 1

Cognitive and Cortical Function

• Consciousness is typically preserved, with approximately 81% of patients maintaining clear consciousness 2
• Neuropsychological symptoms are uncommon in isolated unilateral corona radiata infarcts but may occur with multiple infarcts 1, 2
• Visual field defects are rare in isolated corona radiata lesions 1

Clinical Variants Based on Lesion Extent

Single unilateral infarcts (54% of corona radiata strokes):

• Present with 17 different patterns of complete or partial sensorimotor symptoms with dysarthria 1
• Generally have better prognosis with more incomplete deficits 1

Multiple unilateral infarcts (21% of cases):

• More frequently present with complete sensorimotor deficits 1
• May include neuropsychological impairment 1

Bilateral multiple infarcts (25% of cases):

• Present with bilateral motor and sensory symptoms 1
• Associated with more severe neuropsychological deficits 1
• Carry worse prognosis than unilateral lesions 1

Temporal Course

• Onset is acute and immediate, consistent with ischemic stroke 1
• Prognosis is generally favorable for unilateral lesions, with approximately 64% of patients achieving independent activities of daily living within one month 2
• Recovery occurs over weeks to months, with most improvement in the first 6 months 3

Associated Imaging Findings

• Leukoaraiosis is present in 88% of patients with corona radiata infarcts, reflecting underlying small vessel disease 1
• The presence of bilateral multiple infarcts correlates with more extensive leukoaraiosis 1

Important Clinical Pitfalls

The presentation can be atypical or subtle, particularly when:

• Lesions are small or located in specific portions of the corona radiata 2
• Patients have pre-existing neurological conditions that may mask new deficits 2
• Sensory symptoms are mild and may be overlooked if not specifically assessed 2

Do not confuse corona radiata infarcts with cortical strokes—the absence of cortical signs (aphasia, neglect, apraxia, visual field cuts) in the presence of motor deficits should raise suspicion for subcortical localization 1, 2.