In the UK the National Institue of Clinical Excellence (NICE)
has produced detailed guidance on Parkinson's. It recommends that people with suspected Parkinson's
should be referred to a clinician with specific expertise in the differential diagnosis of this condition. This is as a response to the high level of
mis-diagnosis of Parkinson's and other related conditions.
Diagnosis should primarily be based on the UK Parkinson's Disease Society's Brain Bank Criteria for the diagnosis of
Parkinson's Disease which sets out that a positive diagnosis may be made if a person has Bradykinesia (slowness of movement and an impaired ability to
adjust the body's position) and
at least one of the following:
- muscular rigidity;
- rest tremor;
- postural instability unrelated to primary visual, cerebellar, vestibular or proprioceptive dysfunction.
The criteria lists the following as exclusion criteria for Parkinson's Disease:
- repeated head injury;
- antipsychotic or dopamine-depleting drugs;
- definite encephalitis and/or oculogyric crises on no drug treatment;
- more than one affected relative;
- sustained remission;
- negative response to large doses of levodopa (if malabsorption excluded);
- strictly unilateral features after 3 years;
- other neurological features: supranuclear gaze palsy, cerebellar signs, early severe autonomic
involvement, Babinski sign, early severe dementia with disturbances of language, memory or praxis;
- exposure to known neurotoxin;
- presence of cerebral tumour or communicating hydrocephalus on neuroimaging.
In addition, patients nered to demonstrate three of the following symptoms in order for doctors to arrive at a diagnosis of definite Parkinson's:
- Unilateral onset (one side being affected first);
- rest tremor present;
- progressive disorder;
- persistent asymetry affecting the side of onset most;
- excellent response to levodopa;
- severe levodopa-induced chorea;
- levodopa response for over 5 years;
- clinical course over 10 years.
The NICE guidance recommends that Parkinson's Disease "should be suspected in people presenting with tremor, stiffness, slowness, balance
problems and/or gait disorders." and that Parkinson's Disease "should be diagnosed clinically and based on the UK Parkinson’s Disease Society Brain
Bank Criteria."
The guidance also reviews a number of imaging and scanning techniques but only recommends the use of single photon emission computed tomography
(Spect) for people with tremor where essential tremor cannot be clinically differentiated from pakinsonism.
