Lacunar Infarct of the Putamen: Clinical Presentation
A lacunar infarct involving the putamen typically presents with faciobrachiocrural (face-arm-leg) hemiparesis on the contralateral side, often accompanied by sensory deficits, but does NOT cause acute or delayed parkinsonism or other movement disorders 1.
Primary Motor and Sensory Manifestations
The putamen is supplied by medial perforating branches of the middle cerebral artery, and isolated infarction produces predictable clinical patterns 1:
Pure Putaminal Lesions
Sensorimotor hemisyndrome (most common - 7 out of 9 patients in one series)
- Contralateral weakness affecting face, arm, and leg
- Sensory loss in the same distribution
- May include ataxia (present in 4 of 7 patients)
- Occasionally deep pain in affected limbs 1
Ataxic motor hemisyndrome (2 out of 9 patients)
- Motor weakness with prominent ataxic features 1
Combined Putamen and Globus Pallidus Externus Lesions
When the infarct extends to involve both structures:
- Motor hemisyndrome (3 of 4 patients)
- May include nonfluent aphasia if left-sided (2 patients)
- May include ataxia (1 patient)
- Ataxic sensorimotor hemisyndrome (1 of 4 patients) 1
Associated Cortical-Type Symptoms
Despite being a subcortical lesion, putaminal infarcts can produce symptoms suggesting cortical dysfunction due to disrupted connections with prefrontal, temporal, and parietal cortices 1:
- Left hemineglect (when right putamen affected)
- Aphasia (when left putamen and globus pallidus involved)
- Sensory deficits beyond simple numbness
Rare Manifestations
While uncommon, case reports document atypical presentations:
- Painful tonic spasms: Brief, paroxysmal, painful flexor contractures of contralateral limbs (responsive to carbamazepine, not seizures) 2
- Psychotic symptoms: New-onset schizophrenia-like psychosis has been reported with left putamen infarcts 3
Critical Clinical Pitfall
The absence of movement disorders is a key distinguishing feature: Unlike chronic degenerative diseases of the basal ganglia, acute putaminal infarction does NOT cause parkinsonism, chorea, or other hyperkinetic/hypokinetic movement disorders in the acute or chronic phase 1. If such symptoms develop, consider alternative or additional diagnoses.
Etiologic Considerations
Putaminal lacunar infarcts result from small-artery disease affecting penetrating arteries. Common causes include 1:
- Small-artery disease/lipohyalinosis (most common)
- Artery-to-artery embolism
- Cardioembolism
- Less commonly: undetermined etiology
The clinical presentation alone cannot reliably distinguish the underlying mechanism, requiring appropriate vascular and cardiac workup.