11th August 2024

Parkinson’s plus syndromes

Multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) often present in a similar way to idiopathic PD but have a different pathogenesis. Unfortunately, they are usually unresponsive to dopamine therapy, or at best respond transiently. A trial of levodopa can therefore help to distinguish them from PD.

Multiple system atrophy

MSA is classified according to the predominant motor symptoms: parkinsonian MSA (MSA-P) or cerebellar MSA (MSA-C). The cerebellar subtype may present with cerebellar ataxia rather than parkinsonism. MSA is characterised by prominent early onset autonomic involvement resulting in bladder problems (most commonly retention, also urgency and incontinence), erectile dysfunction, constipation and significant orthostatic hypotension. MRI showing pontine and cerebellar atrophy can support the diagnosis but is not diagnostic.

Progressive supranuclear palsy

Loss of truncal control and vertical gaze are key features of PSP and result in frequent falls and impaired sight. As the disease progresses the patient can also lose eye movements in the horizontal plane. There are a few different subtypes of PSP, which unfortunately progress more rapidly than idiopathic Parkinson’s disease. Midbrain atrophy can support the clinical diagnosis but is not diagnostic.

Corticobasal degeneration

CBD is a type of frontotemporal dementia. The cortex and basal ganglia are affected resulting in personality changes, memory impairment and difficulties with language or maths along with parkinsonian symptoms. It is a clinical diagnosis with apraxia being a common finding. ‘Alien limb’ is a diagnostic feature of CBD and describes the feeling of disassociation the patient has from the involuntary movements in the affected limb.