AKT · Neurology/Movement & neurodegenerationlow yield

Parkinson-plus syndromes (PSP, MSA, CBD)

Neurodegenerative parkinsonism beyond idiopathic Parkinson disease

Overview

A group of neurodegenerative "atypical parkinsonism" syndromes that mimic Parkinson disease but have additional features and respond POORLY to levodopa: progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal degeneration (CBD). The exam skill is spotting the red-flag feature that makes it "Parkinson-plus" rather than idiopathic PD.

Recognise

PSP: early FALLS (backwards) + vertical gaze palsy (especially downgaze) + axial rigidity + a surprised/staring facies
MSA: parkinsonism + early prominent AUTONOMIC failure (postural hypotension, bladder, erectile dysfunction) + cerebellar signs
CBD: markedly asymmetric rigidity/apraxia with an "alien limb"; all three are symmetric-poor responders to levodopa with early postural instability

Red flags

Early falls, early autonomic failure, vertical gaze palsy, or a poor levodopa response = atypical parkinsonism (Parkinson-plus), not idiopathic PD

Differentials & how to tell them apart

Idiopathic Parkinson diseaseasymmetric resting tremor, GOOD and sustained levodopa response, falls and autonomic failure occur LATE — Parkinson-plus has early falls/autonomic features and a poor levodopa response

Drug-induced parkinsonismsymmetrical, antidopaminergic drug history, reversible

Vascular parkinsonismlower-body predominant, stepwise, vascular risk factors/imaging

Investigations

Clinical diagnosis (the additional features + poor levodopa response). MRI may show supportive signs (e.g. "hummingbird" sign in PSP, "hot cross bun" in MSA). Specialist (movement disorder) assessment.

Management

Specialist diagnosis + supportive MDT care (levodopa response is typically poor)

1Recognise the red-flag features, refer to a movement-disorder specialist, and manage supportively (physiotherapy, OT, SALT, falls prevention). A levodopa trial typically gives a poor or unsustained response.Gate: EARLY falls, EARLY autonomic failure, a vertical gaze palsy, or a poor levodopa response shift the diagnosis from idiopathic Parkinson disease to a PARKINSON-PLUS syndrome — these features change prognosis and expectations of treatment
2Treat specific problems (postural hypotension in MSA, dysphagia, communication); palliative/MDT approach as these progress faster than idiopathic PD.

Levodopa trial — usually a POOR/unsustained response (helps confirm atypical parkinsonism) — unlike the good response in idiopathic PD

Supportive: physiotherapy, OT, SALT, falls prevention — the mainstay

Treat specific features — e.g. midodrine/fludrocortisone for MSA postural hypotension

Key points

PSP = falls + vertical gaze palsy; MSA = autonomic failure + cerebellar; CBD = asymmetric apraxia + alien limb. All respond poorly to levodopa — that poor response, with early falls/autonomic features, is the discriminator from idiopathic PD.

Monitor & prognosis

Function, swallow, falls, autonomic symptoms; disease progression.

Faster progression and worse prognosis than idiopathic Parkinson disease.

Source: NICE NG71 (Parkinson’s); ABN