Vascular Parkinsonism

Vascular parkinsonism is a syndrome of gait disturbance and bradykinesia, mainly of the lower body, caused by cerebral small vessel disease or strokes affecting the basal ganglia, thalamus or frontal white matter. It responds poorly to levodopa.

It accounts for about 4 to 12% of parkinsonism in clinical series. Onset is usually after 65 years, and it is associated with hypertension, diabetes, atrial fibrillation and smoking.

Patterns. An acute or subacute form follows a strategic infarct. An insidious form follows diffuse subcortical white matter disease, with slowly progressive gait failure.

Course. Slow progression with falls, cognitive slowing, urinary urgency and pseudobulbar signs. Stepwise decline may occur with new infarcts.

Pathophysiology.

Ischaemic damage disconnects frontal cortex from the basal ganglia and thalamus, or injures the substantia nigra or striatum.

Chronic hypoperfusion and arteriolosclerosis impair the cortico basal ganglia loops of gait.

• Predominantly lower body parkinsonism: wide based, short stepped, magnetic gait with early postural instability and freezing.
• Little or no tremor, and relatively preserved arm swing and facial expression.
• Pyramidal signs, pseudobulbar palsy, urinary urgency and executive dysfunction.
• Poor and short lived response to levodopa.

Red flags.

• Acute onset of gait failure, with new focal signs (stroke).
• Dementia, incontinence and gait failure (normal pressure hydrocephalus).
• Rapid progression, early falls and vertical gaze palsy (progressive supranuclear palsy).

• Clinical diagnosis, with MRI showing extensive white matter disease, lacunes or strategic infarcts that fit the picture.
• Exclude normal pressure hydrocephalus (ventriculomegaly with a high volume lumbar puncture response) and drug induced parkinsonism.
• DAT SPECT is usually normal or shows symmetrical, mild reduction.
• Vascular risk review: blood pressure, glucose, lipids, ECG and ambulatory rhythm monitoring, and carotid imaging when relevant.
• Cognitive assessment and gait analysis.

Differential diagnosis. Parkinson disease, progressive supranuclear palsy, multiple system atrophy, normal pressure hydrocephalus, drug induced parkinsonism, frontal gait disorder and Alzheimer disease with gait impairment.

• Control vascular risk: blood pressure under 130/80 mmHg, stop smoking, glucose control, weight loss and exercise.
• Aspirin 75 mg orally once daily for secondary prevention after ischaemic events (maximum 75 mg daily for long term prevention). Monitor for gastrointestinal bleeding and anaemia. Avoid in active peptic ulcer, bleeding disorders and aspirin hypersensitivity; use caution in asthma and renal impairment (avoid when eGFR is under 10); acceptable in pregnancy only under specialist advice.
• Atorvastatin 80 mg orally once daily at night, aiming for LDL cholesterol under 1.8 mmol/L. Maximum 80 mg daily; limit to 20 mg daily with clarithromycin. Monitor liver function at baseline and at 3 months, creatine kinase if muscle symptoms occur, and lipids at 4 to 12 weeks. Avoid in active liver disease and pregnancy; no renal adjustment.
• Levodopa test course: co-careldopa equivalent to 50 mg levodopa orally three times daily after food, increased by 100 mg levodopa daily each week to a usual 300 to 600 mg daily in 3 divided doses. Maximum 1000 mg levodopa daily. Assess at 3 months and stop if there is no benefit. Monitor nausea, postural hypotension, hallucinations and dyskinesia. Avoid with non-selective monoamine oxidase inhibitors and in angle closure glaucoma; no renal adjustment; avoid in pregnancy unless essential.
• Physiotherapy for gait and balance, with cueing strategies, walking aids, home safety review and falls prevention.
• Treat urinary symptoms, depression and sleep disturbance.
• Shunt surgery only when normal pressure hydrocephalus is confirmed.

Monitoring. Review at 3 months, then every 6 months; track gait, falls, cognition and vascular risk targets.

Referral and escalation. Neurology and stroke or geriatric services; physiotherapy and occupational therapy; neurosurgery for hydrocephalus.

Special groups. Older adults: assess for orthostatic hypotension and polypharmacy before adding drugs.