A recent survey showed that 94 per cent of GPs felt they had no specialist knowledge of Parkinson's disease and under a third did not refer patients with a suspected diagnosis immediately to a specialist.
The GP is likely to be the first healthcare professional to recognise the features of Parkinson's disease in a patient and should feel confident in making the diagnosis.
The onset of Parkinson's disease is usually insidious. The primary symptoms are tremor, rigidity or stiffness, bradykinesia with hypokinesia, and postural instability.
Not all these symptoms may be present. Tremor worsens with stress and decreases with alcohol and intentional actions. Symptoms are usually unilateral initially but often become bilateral as the disease progresses.
Other features can be remembered by the seven Fs.
Handwriting may become small (micrographia) and there may be excessive sweating, greasy skin, depression and cognitive impairment including dementia.
Patients may find it difficult to roll over in bed, rise from a chair, swallow - which causes excessive dribbling - or do up buttons. Sleep disturbance is common with vivid dreams.
Autonomic symptoms increase with disease progression and include constipation, urinary incontinence, weight loss and sexual dysfunction.
It is important to take a careful medication history because several drugs can cause parkinsonism, including haloperidol and other antipsychotics, valproate and possibly some SSRIs. Recent evidence suggests a possible link with statins.
Neurological examination should include gait observation, which will reveal festination and loss of arm swing, dysdiadochokinesia - inability to do rapid alternating movements - and positive glabellar tap.
Assessing the muscle tone will reveal rigidity and cogwheeling. Asking the patient to wave vigorously with the contralateral arm will enhance the cogwheeling and rigidity.
Essential tremor is often confused with Parkinson's disease, however, it is usually bilateral, the tremor has a higher frequency and is often intentional rather than resting. Other differential diagnoses include dementia and depression.
Other conditions include the Parkinson-plus syndromes: multi-system atrophy and progressive suprabulbar palsy. These progress more rapidly and are less amenable to medication.
Role of the GP
Patients with suspected Parkinson's disease should be referred quickly and untreated to a specialist with expertise in movement disorders, specifically Parkinson's.
The diagnosis is sometimes difficult even for a specialist and the patient may be investigated with a SPECT scan or PET scan, which can demonstrate degeneration of the cells in the substantia nigra.
The diagnosis of Parkinson's disease should be reviewed regularly and, if atypical features develop, be reconsidered.
The choice of drug will depend on age at onset, severity of disease, the progression and lifestyle characteristics of the patient.
Treatment is very much a negotiation between the patient and the healthcare team. There should be regular access to physiotherapy, occupational therapy, and speech and language therapy.
It is important to consider palliative care in all stages of the disease and patients and carers should be able to discuss terminal issues with healthcare professionals, including the GP.
Most health authorities have specialist nurses trained in the care of patients with Parkinson's disease. They provide an invaluable service and close contact between them and the GP is necessary for optimal management.
Visits by the specialist nurse help to monitor treatment.
Each patient must be individually evaluated to determine which drug regimen will suit them best. Medication should be commenced and monitored by the specialist with the help of the specialist nurse.
Many, newer, medications including combination tablets (carbidopa/levodopa with entacapone) and patches, give a smoother dose response.
Some problems in patients with Parkinson's disease can be managed effectively in primary care, for example insomnia and anxiety or depression, which respond well to mirtazapine at night. Dribbling can be treated with atropine eye drops - a drop on the tongue when required can be effective.
The main message in the management of Parkinson's disease is early recognition and referral to a specialist. Involvement of other healthcare professionals will enable optimum management as the disease progresses.
Dr Lance is a GPSI in movement disorders in Woking, Surrey
THE SEVEN Fs
- Festinating shuffling gait.
- Facial blankness.
- Feeble monotonous voice.
- Failure to swallow.