Right Hemispheric Stroke with Contralateral Hemiparesis
This patient requires immediate brain MRI to confirm a right hemispheric stroke causing left-sided weakness and contralateral gaze preference, followed by urgent stroke protocol activation. 1
Immediate Diagnostic Workup
Obtain urgent brain MRI with high-resolution sequences to localize the lesion causing this constellation of findings. 1 The combination of left-sided weakness, rightward gaze preference, and upward lateral gaze weakness without facial asymmetry localizes to a right hemispheric lesion affecting the frontal eye fields and motor cortex. 2
Key Localizing Features
Rightward gaze preference (conjugate deviation) indicates a right frontal lobe lesion, as the frontal eye fields drive contraversive eye movements—the eyes deviate toward the side of the lesion and away from the hemiparetic side. 2
Left-sided weakness without facial asymmetry suggests cortical involvement sparing the facial motor area or a subcortical lesion affecting the internal capsule while sparing corticobulbar fibers. 3
Upward lateral gaze weakness may indicate involvement of pathways projecting through the diencephalon or suggest a more extensive lesion affecting vertical gaze control mechanisms. 4, 2
Critical Imaging Considerations
Standard CT may miss small lesions, particularly in the thalamic-mesencephalic region if vertical gaze pathology is prominent. 1 However, given the clear hemispheric signs (hemiparesis and conjugate gaze deviation), MRI brain with diffusion-weighted imaging will definitively identify acute ischemic stroke. 1
Do not delay neuroimaging based on the absence of facial weakness—this finding does not exclude significant stroke and may reflect anatomical sparing of facial motor pathways. 3
Acute Stroke Management Protocol
Immediate Interventions
Activate stroke protocol immediately and assess for thrombolysis eligibility if within the appropriate time window. 1
Maintain cerebral perfusion pressure >60 mmHg through volume replacement and/or vasopressors as needed. 1
Implement strict glycemic control and treat hyperthermia aggressively, as both worsen stroke outcomes. 1
Neurological Monitoring
Assess for evolving deficits including worsening motor weakness, changes in level of consciousness, or development of additional cranial nerve findings that might indicate stroke progression or hemorrhagic transformation. 5
Management of Gaze Abnormalities
Acute Phase
Do not pursue surgical correction of eye movement abnormalities in the acute phase—the pathology is supranuclear (cortical/subcortical) rather than muscular, and gaze palsies from hemispheric strokes typically improve with time as diaschisis resolves. 1
If Diplopia Develops
Small vertical deviations can be managed with prism glasses if diplopia becomes symptomatic during recovery, though lateral incomitance may limit successful implementation. 5, 1
Rehabilitation Phase
Initiate early rehabilitation in the intensive care unit once the patient is hemodynamically stable, as early mobilization improves functional outcomes. 1
Progressive mobilization should begin after resolution of the acute phase and absence of signs of significant intracranial hypertension. 1
Critical Pitfalls to Avoid
Do not assume a benign etiology based on the absence of facial weakness—this presentation represents a significant stroke requiring immediate intervention. 1
Do not delay thrombolysis to obtain ophthalmologic consultation for the gaze abnormalities—time is brain, and the gaze findings do not contraindicate acute stroke treatment. 1
Do not attribute the upward gaze weakness to isolated midbrain pathology without imaging confirmation, as this could be part of a larger hemispheric stroke affecting descending pathways. 4, 2
Do not pursue strabismus surgery for any residual gaze deviation until at least 6 months post-stroke, as spontaneous improvement is common and the pathology is supranuclear. 5, 1