Parkinson's Disease

Diagnosis

The costs of treatment (health and social care) have been estimated at between £560,000 and £1.6 million per 100,000 population (i.e. per 160 patients, or an annual cost of between £3,500 and £10,000 per person. Significant cost drivers include the onset of motor fluctuations, psychiatric symptoms, and institutional care [1,2,3].

Diagnosis of PD remains predominantly clinical. Diagnosis can be difficult and relies on the recognition of the cardinal features of bradykinesia, rigidity and tremor. This can be complicated in the elderly by the presence of co-morbidity such as dementia or cerebrovascular disease.

Diagnostic error is common with an error rate of up to 50 per cent in a community-based study [4]. Accurate diagnosis is the cornerstone for predicting prognosis and planning of management. It is strongly recommended, therefore, that all patients with a suspected diagnosis of PD be referred for specialist assessment by an experienced clinician, ideally before treatment is started. The use of standard diagnostic criteria, such as the UK PDS Brain Bank has been shown to increase diagnostic accuracy (see appendix) [5].

The manner in which the diagnosis is communicated to patients and carers is very important and has been shown to have a significant effect on quality of life many years later [6]. This should be carried out by an experienced clinician allowing adequate time and backed up with written information. It is good practice to arrange a second consultation to ensure that the information imparted has been understood and to allow further questions. The PD Nurse Specialist has a valuable role to play in this process.

Investigation

Response to treatment is an important aspect when establishing the diagnosis. However, acute challenge tests using either oral levodopa or subcutaneous apomorphine are insufficiently sensitive or specific are not recommended for routine use [7].

C.T. brain scans show no abnormality in PD and are likewise not recommended routinely. In selected patients with an atypical presentation (e.g. prominent gait disorder, dementia) a C.T. scan may be of value in establishing an alternative diagnosis such as multiple cerebral infarcts or hydrocephalus. Laboratory testing will sometimes be appropriate - e.g. the exclusion of Wilson's disease or other more common confounding issues such as thyroid function and syphilis serology.

In cases of diagnostic uncertainty, access to functional imaging using FP-CIT SPECT scanning can be helpful in distinguishing parkinsonian from non-parkinsonian syndromes.

Assessment

Although the earliest and more apparent effects of PD are on the motor system, non-motor problems are also very important in contributing to the overall impact of the condition. It is important, therefore, that assessment covers the physical, mental and social domains [8]. Comprehensive assessment will necessarily be multidisciplinary. Physical assessment should include not only motor but sensory and autonomic function as well as the impact on activities of daily living, speech and swallowing. The mental domain should include assessment of cognitive function and mood as both dementia and depression are common. The social environmental domain includes assessment of quality of life.

A number of standardised assessment tools are available and their use is encouraged. Routine use of such tools allows 'hidden' problems to be identified and allows monitoring of progression. Standardised assessment also facilitates clinical audit. Appropriate tools include the Unified Parkinson's Disease Rating Scale (UPDRS) for motor assessment, Mini Mental State Examination (cognitive) , Geriatric Depression Scale (GDS15) and PDQ39 (quality of life). More specialised assessments are carried out by the relevant therapists as the need arises. The NMS Quest is a recently validated screening tool (accessed March 07) for the detection of non motor symptoms in PD.

Management of PD in elderly patients is made more challenging by the common occurrence of co-morbidity, both physical and psychiatric. This not only makes diagnosis more difficult but also presents management problems. Associated polypharmacy increases the potential for drug interactions and adverse effects. A full medical assessment is therefore essential. Specialists in Geriatric Medicine who are trained and experienced in managing complex problems in the elderly are well placed to carry out this function.

PD is a progressive condition and patients deteriorate gradually over time. This can be insidious with increasing impairment and handicap going unrecognised. Regular, planned follow-up by the specialist team is therefore advised.

Stage of disease can be classified according to the Hoehn & Yahr scale, which ranges from 1.0 (unilateral involvement only) to 5.0 (wheelchair bound or bedridden). This, however, concentrates on impairments rather than disability or handicap and is of limited use in the management of individual patients. A more useful paradigm has been developed which describes four stages in the evolution of the disease through diagnosis, maintenance, complex and palliative stages [9]. The appropriate management at each of these stages is outwith the remit of this short paper, but described in the 'guideline papers' and the NICE clinical guideline referenced below [7,10,11].

As the disease progresses, dependency and psychiatric co-morbidity increase. In order to address the spectrum of need, a comprehensive service providing outpatient clinics, Day Hospital , inpatient assessment / rehabilitation and long term care is required.

Good Practice Statements

A number of 'guidelines' have been published, and are referenced below [7,10,11].

U.K. Specialist Guidelines [7] written primarily for the specialist practitioner.

Primary Care Guidelines [10] written primarily for the primary care team in the four stage structure [9].

American Algorithms [11] contain management issues and algorithms for common situations arising in PD - primarily for the specialist practitioner.

NICE have recently published a clinical guideline which is referenced under further reading.

Models of Service

In the U.K, the identified medical specialist may be a geriatrician or a neurologist. It is helpful if the two departments can work collaboratively, and will benefit from close working relationships with a PD Nurse Specialist and a dedicated Multi-disciplinary team [12]. This will normally have elements of physiotherapy, occupational therapy, speech and language therapy, dietetics, and psychology. Exact relationships and location vary depending on the types of service configuration, management structures, rurality/population density, and transport availability. Some departments offer programmed multi-disciplinary sessions - often at diagnosis and at intervals thereafter. Others have open access or referral protocols, depending on local policies [13].

Relationships

In addition to the components mentioned above, close working relationships are desirable with Neurosurgery, Psychiatry (including old age psychiatry), Psychology, and other disciplines.

Training / Education

Hitherto, knowledge of PD and movement disorders has been acquired in a rather indeterminate manner during general professional and higher specilaist training in geriatric medicine. With the increasing specialisation and subspecialisation of Modernising Medical Careers to the standards and competencies defined by PMETB this approach will become increasingly untenable. Experience in other specialties and sub-specialties suggest that some form of accreditation will become necessary if not a formal CCT in Movement Disorders. Reflecting this possible direction of travel the PD Academy was founded in 2002 and has run 9 formal Masterclasses for geriatricians who are keen to learn more about running a Service – 3 more have been recruited to and/or are planned. Similar courses are available for specialist nurses and other disciplines. Attendance at specialist meetings (Parkinson's Disease and Movement Disorders) is desirable as part of the portfolio of continuing professional development (CPD/CME).