What are the next steps in managing a new onset of leaning to the right while walking in an elderly woman with Alzheimer's disease and subcortical arteriosclerotic encephalopathy?

Acute Neurological Assessment Required for New-Onset Lateral Gait Deviation

This patient requires urgent clinical evaluation to rule out an acute posterior circulation stroke or other serious neurological event, given her vascular risk factors (diabetes, hypertension, subcortical arteriosclerotic encephalopathy) and the acute onset of lateropulsion during ambulation. 1

Immediate Clinical Assessment

Key Neurological Examination Components

The following specific findings must be assessed urgently:

• Skew deviation testing: Perform upright-supine test to evaluate for vertical misalignment of the eyes, which suggests brainstem or cerebellar pathology 1
• Ocular motor examination: Check for nystagmus, internuclear ophthalmoplegia, impaired saccades, or vertical gaze palsy (characteristic of progressive supranuclear palsy or posterior fossa stroke) 1
• Cerebellar testing: Perform finger-to-nose and heel-to-shin tests to assess for dysmetria, which localizes to cerebellar pathways 2
• Cranial nerve assessment: Evaluate for new cranial nerve palsies, Horner's syndrome, or hearing loss 1
• Motor and sensory examination: Check for hemiparesis, sensory loss, or ataxia suggesting brainstem or cerebellar involvement 1
• Gait observation: Document whether the lean is consistent, worsens with eyes closed, or is associated with head tilt 1, 3

Critical Red Flags

Any of the following warrant immediate hospital transfer for neuroimaging:

• Vertical diplopia, head tilt, or subjective visual tilt 1
• New nystagmus or ocular motor abnormalities 1
• Ataxia, dysmetria, or limb incoordination 2
• Associated vertigo, nausea, or vomiting 1
• New weakness, sensory changes, or dysarthria 1

Differential Diagnosis Priority

Most Urgent: Posterior Circulation Stroke

Given her cardiovascular risk factors (diabetes, hypertension, hyperlipidemia) and moderate subcortical arteriosclerotic encephalopathy, acute brainstem or cerebellar ischemia is the primary concern 1. Lateropulsion (leaning to one side) is a classic presentation of lateral medullary or cerebellar stroke 1.

Other Serious Considerations

• Skew deviation from vestibular pathology: Can present with lateropulsion and is associated with brainstem, cerebellar, or peripheral vestibular lesions 1
• Progressive supranuclear palsy: Presents with axial rigidity, falls, and gait instability in elderly patients, though typically has vertical gaze palsy 1
• Progression of subcortical arteriosclerotic encephalopathy: Can cause subacute focal deficits and motor signs 4, 5

Diagnostic Approach

Neuroimaging

MRI brain with diffusion-weighted imaging is the preferred modality to evaluate for:

• Acute ischemic stroke in posterior circulation 2
• Progression of white matter disease 4, 6
• Cerebellar or brainstem structural lesions 2

CT head can be performed if MRI is unavailable, though it has limited sensitivity for posterior fossa pathology 1.

Timing of Imaging

Imaging should be performed urgently (within hours) if any red flag features are present, as this could represent acute stroke requiring time-sensitive intervention 1. Even with Level of Care B designation, diagnostic imaging that could change management (e.g., identifying reversible causes, guiding antiplatelet therapy, or preventing progression) remains appropriate 1.

Management Considerations

If Examination is Benign

If neurological examination reveals no red flags:

• Orthostatic blood pressure measurement to exclude orthostatic hypotension (common with her medications including Candesartan and Forxiga) 1
• Medication review: Evaluate for centrally acting medications that could impair balance 1
• Vision assessment: Check for visual impairment contributing to gait instability 1
• Physical therapy referral for gait and balance training 1, 3

Fall Prevention

Regardless of etiology, implement immediate fall precautions:

• Ensure walker is being used consistently 1
• Assess home environment for trip hazards 3
• Consider supervised ambulation until diagnosis is established 1

Clinical Pitfalls to Avoid

• Do not attribute new lateropulsion solely to progression of known dementia or white matter disease without excluding acute stroke 1, 5
• Do not delay evaluation because symptoms are "mild" or patient denies weakness—posterior circulation strokes can present subtly 1
• Do not assume this is simply a fall risk issue—new asymmetric gait deviation requires neurological explanation 1, 3

The key decision point is whether neurological examination reveals any red flag features suggesting acute posterior fossa pathology, which mandates urgent hospital transfer and neuroimaging. 1