Liz Scott, BA, RGN, is Parkinson’s disease nurse specialist, Buckinghamshire Hospitals NHS Trust.
Parkinson’s disease is a progressive disabling disorder characterised by learned voluntary movements, such as bradykinesia (difficulty in initiating and slowness in executing movement) and either rigidity or resting tremor or both (Box 1).
It occurs in people of all ages but prevalence increases with age. In the UK there are an estimated 120,000 people with Parkinson’s.
The cause of the disease is unknown but genetic and environmental factors may play a part. Symptoms arise when the melanin-containing cells of the substantia nigra degenerate resulting in depletion of dopamine, a neurotransmitter needed to facilitate the smooth functioning of the basal ganglia (the movement centre of the brain).
Diagnosis is based on clinical observation as there are no diagnostic tests to confirm the disease. However, unilateral onset of symptoms and a positive response to medication are factors that can confirm that a person has Parkinson’s.
The presence of bradykinesia is essential to confirm a diagnosis of Parkinson’s disease. This can be observed by asking a person to open and close their thumb and fingers as rapidly as possible. In people with Parkinson’s speed and amplitude of movement will deteriorate.
It can also be seen in handwriting when words in a sentence start off a certain size but become smaller and smaller as the writer continues. Other signs include walking steps being taken closer together and a reduction in heel strike and arm swing on the affected side.
The rigidity detected in patients with the disease is distinct from spasticity and is present throughout a range of movements. It can also be observed in a lack of facial expression described as hypomimia. This can sometimes give the mistaken impression that a person is anxious, hostile, unhappy or less intelligent (Pentland, 1987). Stiffness and rigidity can affect posture and it is as though the brain has reset its posture default settings so that it seems normal to walk on the balls of the feet, flexed at the knees, hips and waist. Such a posture pushes the centre of gravity forward and coupled with a loss of postural reflexes increases the risk of falling.
Tremor is the most obvious sign of Parkinson’s, although 30% of people with the disease do not experience this symptom. Tremor in Parkinson’s occurs during resting and disappears when the person is active. Compared with bradykinesia and rigidity, tremor is the least disabling symptom of Parkinson’s. People with the disease can often complete quite complex tasks such as shaving, drawing, painting and knitting. However, a rest tremor can be embarrassing and is often amplified by stress and anxiety.
Bradykinesia, rigidity and tremor are not the only symptoms of Parkinson’s disease. Many people with the disease are also thought to be depressed. It is likely that depression in people with Parkinson’s is under-diagnosed.
Dysphoria is sometimes experienced by people with Parkinson’s. Feelings of anxiety, panic and hopelessness are common, although they tend to come and go, and can often mirror the effectiveness of medication.
For many years the literature failed to mention pain in connection with the condition. Muscle cramping, aching and dystonia can be very uncomfortable. Occasionally people complain of abdominal discomfort that may be a form of dystonia.
At diagnosis there is usually no rush to treat mild symptoms of Parkinson’s and age at onset, general health and personal circumstances influence the choice of drug.
The best treatment approach would be to deliver dopamine directly to the brain. Unfortunately, dopamine cannot be taken orally as it will not pass through the blood/brain barrier. However, levodopa - the precursor of dopamine - will cross this barrier, where it is decarboxylated to dopamine by the surviving neurons. Excess dopamine is then stored and released when necessary. As the disease progresses the degenerating neurons are no longer able to store and release dopamine when required. Therefore stronger doses taken more frequently are needed to keep symptoms at bay.
Although co-careldopa (levodopa and carbidopa) and co-beneldopa (levodopa and bensezaride) are standard treatments for Parkinson’s, other medications have been developed as adjunct therapy or to postpone the need for levodopa. This is because there are a number of long-term side-effects associated with its use.
The effects of levodopa can wear off before the next dose is due and therefore regular review of dosing and timing are required. The most serious side-effects include dyskinesia (involuntary writhing movements) and motor fluctuations. Almost all people under the age of 50 years with the disease will develop dyskinesia, which can be as disabling as the condition the drug is trying to treat.
Dyskinesia can occur either at peak dose or at the end of dose. It can vary from mild to moderate or severe. Motor fluctuations can occur despite taking levodopa at regular intervals and may occur at different times of the day. A person can be mobile and independent but within a matter of minutes the effects of the drug can wear off and she or he is rendered immobile and dependent. This is called the on/off phenomenon.
Dopamine agonists switch on selected dopamine receptor sites in the brain, mimicking the action of dopamine. They are associated with a lower incidence of dyskinesia but a slightly higher risk of the patient developing neuropsychiatric side-effects such as hallucinations and delusions. Dopamine agonists can delay the need for levodopa by up to five years (Rascol et al, 2000). Monoamine oxidase (MAO) type B inhibitors inhibit the enzyme that breaks down excess dopamine in the brain thus allowing it to be available for longer. Both classes of drug can be used as monotherapy or as an adjunct to levodopa.
At diagnosis the drugs of choice are dopamine agonists or MAO type B inhibitors. The use of dopamine agonists and selegiline is associated with an increased risk of developing confusion, visual hallucinations and delusions, and for this reason patients over the age of 75 years are more likely to start treatment with levodopa.
Anticholinergics may be used in younger patients with troublesome tremor but should not be used for prolonged periods because of the risk of developing side-effects such as short-term memory loss, confusion, blurred vision, constipation and urinary retention.
In recent years the use of amantadine has increased. Amantadine is a weak NMDA (n-methyl-d-aspartate) antagonist and has been shown to reduce the level of dyskinesia by approximately 45% for up to eight months (Thomas et al, 2004). Use of catechol-o-methyl transferase inhibitors has been shown to enhance the effect of levodopa. If the complications of long-term levodopa use prove intolerable, use of the dopamine agonist apomorphine delivered either through intermittent subcutaneous injections or continuously via an infusion can significantly reduce the amount of levodopa needed, thereby reducing side-effects.
Medication should relieve the symptoms of Parkinson’s. Before a person is said to be unresponsive to medication they must have taken increasing doses for a reasonable period of time. However, if after this time the symptoms remain untreated then the diagnosis must be reviewed.
Differential diagnoses include drug-induced Parkinsonism, multiple system atrophy, progressive supranuclear palsy, Lewy body disease and arteriosclerotic pseudo-Parkinsonism.
A good response to medication does not guarantee consistently good control of the symptoms of Parkinson’s disease. Such control requires frequent monitoring by the patient, their neurologist or a physician with a special interest in Parkinson’s supported by a nurse specialist.
Recognising poor symptom control
If someone is anxious or stressed their symptoms will worsen but may improve when the stress is removed. If a patient in hospital has an infection their Parkinson’s disease control will be poor until they recover.
It is important to ask the patient how they are and listen to what relatives tell you about their usual abilities. Consider whether their abilities vary during the day. For example, do they go to the toilet unaided in the morning but need help later in the day?
Patients come into hospital with set times for taking their medications. These times rarely coincide with drug round times. If someone is used to taking their medication at certain times they should be allowed to self-medicate if they are able to do so. If they are not able to do so nursing staff need to give drugs outside usual drug round times.
Particular care needs to be taken if patients are ‘nil by mouth’ or have difficulties swallowing tablets. Sudden withdrawal of long-term dopaminergic therapy can give rise to a rare but potentially fatal condition called neuroleptic malignant syndrome. NMS is characterised by rigidity, stiffness and hyperpyrexia, and dopaminergic drugs must be restarted as soon as possible to prevent possible renal failure and rhabdomyolysis (Ward, 2005).
Co-beneldopa is available in dispersible form and is useful for people who have difficulty swallowing. It can be administered via nasogastric tubes and percutaneous endoscopic gastrostomy tubes.
The following case study illustrates some of the difficulties involved in treating Parkinson’s disease.
Albert Smith (not his real name) is 80. He was diagnosed with Parkinson’s disease by his GP three years ago and initially took co-beneldopa 62.5mg three times a day with food. At first the co-beneldopa was effective. ‘It was like a miracle,’ he said. ‘My walking improved, the shake in my hand went away for most of the day and I could get out of my chair more easily.’ Three years later Mr Smith found his shuffling walk and tremor had returned. He had read that Parkinson’s gets worse over time and that eventually co-beneldopa does not work so he had accepted that he had to put up with it.
Mr Smith needed to take stronger and more frequent doses of co-beneldopa at least half an hour before food (Kemster et al, 1994). This is because levodopa is a large, neutral amino acid that competes with large, neutral amino acids derived from protein, therefore more will be absorbed if taken before food. Doses are best spaced equally through the day. Mr Smith gets up at 7.30am so it made sense for him to take his co-beneldopa half an hour before getting out of bed and then at four-hourly intervals.
Mr Smith’s dose of co-beneldopa was increased and his mobility and tremor improved. He was referred to the day hospital and benefited from physiotherapy and a full occupational therapy assessment. Now he is under the care of a hospital consultant with a special interest in Parkinson’s and has access to a nurse specialist. Mr Smith will be kept under regular review.
Many people with Parkinson’s disease experience poor symptom control despite the existence of knowledge and expertise to optimally treat symptoms. Regular monitoring by health professionals with expertise in this disease area is vital.
Identifying poor symptom control and taking the appropriate action can significantly improve the patient’s quality of life, thereby impacting on their carers and family. Allowing patients to self-medicate while in hospital or enabling staff to give drugs outside set drug round times is good practice and promotes optimum disease control.
Each week Nursing Times publishes a guided learning article with reflection points to help you with your CPD. After reading the article you should be able to:
- Understand the motor symptoms of Parkinson’s disease;
- Know the non-motor symptoms of Parkinson’s;
- Be familiar with the drug treatments for the disease;
- Understand how to recognise poor symptom control.
Use the following points to write a reflection for your PREP portfolio:
- Write about your area of work and why this article is relevant to your practice;
- Reflect on the last time you encountered a patient with Parkinson’s disease;
- Identify a piece of information that could have informed your care of that patient;
- Consider how you will apply what you have learnt to the next patient you encounter who has Parkinson’s;
- Explain how you will disseminate this information to your colleagues.
This article has been double-blind peer-reviewed.
For related articles on this subject and links to relevant websites see www.nursingtimes.net