1. Be aware of unusual symptoms – not all cases present classically
You need to know what to look for and, crucially, what to ask about:
• The most common reason for delayed diagnosis is that patients and GPs may attribute symptoms to ageing.
• The cardinal motor features of Parkinson’s are tremor, rigidity, bradykinesia and postural instability, but not all patients may exhibit all of these.
• Walking problems, difficulties with balance, turning over in bed and problems with fine manual tasks such as using buttons, are classic motor presentations.
• The diagnosis is often overlooked when elderly patients complain of ‘unusual’ symptoms. Non-motor symptoms such as sleep disturbance (especially shouting or hitting out during REM sleep), reduced sense of smell, anxiety/depression, and constipation may be harbingers of the disease and can be helpful in discriminating Parkinson’s from other movement disorders. You should ask specifically about these symptoms.
• Typically, onset of Parkinson’s is with unilateral, or at least asymmetrical, motor symptoms and signs.
• Arm and shoulder stiffness may mimic a frozen shoulder.
• Unilateral loss of arm swing may be the only discernible clinical sign.
2. Patients with suspected Parkinson’s should be referred to a specialist untreated within six weeks
Patients with suspected Parkinson’s should not be started on treatment by their GP as this can mask symptoms and make assessment more difficult.
Not all patients need to start treatment at diagnosis. Clarity over what symptoms are being treated and the likely response is also required. The placebo response to treatment in Parkinson’s and other movement disorders is high, and may lead to a false sense of security in the (possibly incorrect) diagnosis.
3. Not everyone who shakes has Parkinson’s
Essential tremor and other forms of tremor are still frequently misdiagnosed as Parkinson’s. Rest tremor is the most common type of Parkinson’s tremor, but action or postural tremor may also occur.
Bear in mind that 30% of Parkinson’s patients never have a tremor. A head tremor is rare in Parkinson’s, but jaw and lip tremors are common.
Distracting the patient, getting them to carry out a calculation or do something with the unaffected side, can bring out an otherwise covert tremor.
Parkinsonian tremor is usually non-disabling, but also notoriously difficult to treat. It should therefore not be used as the sole measure of effective therapy, contrary to most patients’ beliefs.
4. All patients should be referred to a Parkinson’s disease nurse specialist (PDNS) at diagnosis
PDNSs help manage Parkinson’s throughout the condition. The PDNS provides information, support and advice, medicines management, crisis management and helps prevent admissions. Parkinson’s nurses can refer patients to the appropriate member of the multidisciplinary team, and will refer patients for specialist rehabilitation – occupational therapy, physiotherapy, speech and language therapy – when necessary.
5. Levodopa (co-careldopa or co-beneldopa) remains the most effective treatment for Parkinson’s motor symptoms and doesn’t ‘stop’ working
The vast majority of patients will have an excellent response to levodopa from the start. If they don’t, the diagnosis should be reconsidered.
It is a commonly held misapprehension that with time, levodopa ‘stops’ working – this is wrong. Patients who are responsive to levodopa at diagnosis should remain responsive, although the magnitude of the benefit will wane with time.
6. Dyskinesias (involuntary movements) and motor response fluctuations are complications of drug therapy in Parkinson’s
They are not part of the ‘natural, untreated history’ of the condition. The risk of motor complications increases with duration and dose of therapy, and dyskinesias are usually associated with peaks in plasma drug concentration.
Wearing off – the tendency for patients’ symptoms and signs to reappear before the next dose of drug – is the most common type of motor response fluctuation, and is associated with troughs in drug plasma concentration. Sometimes, motor complications can be managed by giving smaller doses of medication, more frequently.
7. Non-ergot dopamine agonists (DAs) ropinirole, pramipexole and rotigotine patch are effective alternatives or adjuncts to levodopa
But there are important risks to be considered:
• Impulse control behaviours – specifically hypersexuality, compulsive shopping, gambling and eating – occur in around 15% of patients who are treated with DAs.
• Patients, and critically their carers, must be warned about this, and frequent enquiry about subtle features of impulse control behaviours must be made.
8. Non-motor symptoms have been historically under-recognised and include sleep disturbance, autonomic dysfunction, psychiatric and cognitive complications.
The pathophysiological basis of non-motor symptoms involves neurotransmitters other than dopamine. Therefore, patients with severe non-motor symptoms usually respond poorly to dopaminergic therapies, often leading to unrealistic expectations and disappointed patients and carers.
9. Depression and anxiety are common non-motor symptoms in Parkinson’s
Depression and anxiety may predate the onset of the motor symptoms by years, and may be resistant to treatment with antidepressants, although SSRIs, SNRIs and mirtazapine can all be useful.
Apathy and loss of interest in things (anhedonia) is common and may occur in the absence of depression. Carers find these symptoms particularly difficult to cope with.
10. Visual, though usually not auditory, hallucinations are increasingly common as Parkinson’s progresses
These hallucinations present a major management challenge, and may herald the onset of dementia. Hallucinations may be drug induced or triggered by intercurrent infection. Patients and carers find hallucinations very distressing – onset that is unrelated to infection is strongly predictive of nursing home placement.
Screening for infection should be rigorous and is the first management step. Stopping or reducing all unnecessary drugs, including anti-muscarinics for the bladder, dopamine agonists and amantadine should also be considered.
Cholinesterase inhibitors such as rivastigmine may be useful in controlling hallucinations.
Dr Paul Worth PhD FRCP is consultant in neurology and movement disorder specialist at Spire Norwich Hospital, Spire Cambridge Lea Hospital and Addenbrooke’s Hospital, Cambridge
Further reading
• Worth PF. How to treat Parkinson’s disease in 2013. Clinical Medicine 2013;13:93-6.
• SIGN. Diagnosis and pharmacological management of Parkinson’s disease: a national clinical guideline. Edinburgh, 2010.
