Symptoms of Right Thalamic Lacunar Infarct
A right thalamic lacunar infarct typically presents with contralateral (left-sided) sensory disturbances, which may be accompanied by motor weakness, ataxia, and cognitive changes depending on the specific thalamic nuclei affected. 1, 2
Primary Sensorimotor Symptoms
- Left-sided sensory disturbances (paresthesia, numbness, tingling) are the most common presenting symptoms, often affecting the face, arm, and leg 1, 3
- Left-sided hemiparesis (weakness) may occur, though it can be mild or subtle compared to other stroke locations 1
- Ataxic hemiparesis - a combination of weakness and incoordination affecting the left side - can occur with dorsolateral thalamic lesions 1
- Sensory loss to primary modalities (touch, temperature, vibration, position sense) on the left side of the body 3
Movement Disorders
- Involuntary movements such as hemi-chorea (irregular, dance-like movements) affecting the contralateral (left) limbs may occur, though this is relatively rare 4
- Tremor or other movement abnormalities may develop, particularly with involvement of specific thalamic nuclei 4
Cognitive and Behavioral Symptoms
- Apathy and loss of initiative may be prominent, especially with involvement of the intralaminar nuclei 2
- Attention and concentration problems are common 2
- Executive function disturbances (problems with planning, organization, and mental flexibility) 2
- Memory deficits in both visual and verbal domains, often characterized by retrieval difficulties rather than encoding problems 2
Clinical Considerations and Caveats
- Unlike many lacunar syndromes, thalamic infarcts may present with isolated sensory symptoms without motor involvement 3
- The specific constellation of symptoms depends on which thalamic nuclei are affected by the infarct 1, 2
- Symptoms may be subtle and can be mistaken for peripheral nerve disorders, especially when sensory symptoms predominate 3
- SPECT imaging may show hypoperfusion in the ipsilateral frontal cortex due to thalamocortical disconnection 2
Prognosis
- Lacunar infarcts generally have a favorable short-term prognosis with low early mortality 5
- However, they carry an increased risk of long-term complications including recurrent stroke and cognitive decline 5
- Asymptomatic progression of small-vessel disease is a typical feature of lacunar infarcts 5
Diagnostic Considerations
- MRI with diffusion-weighted imaging is the preferred modality to detect acute thalamic lacunar infarcts 1, 4
- Functional imaging such as SPECT may reveal perfusion abnormalities in the thalamus and connected cortical regions 2, 4
- A thorough assessment of vascular risk factors, particularly hypertension and diabetes mellitus, should be performed as these are major risk factors for lacunar stroke 5