Parkinson's disease

Path to diagnosis of Parkinson's disease

 
The process of managing the diagnosis and treatment of illness in the NHS has always been divided between the primary care team (the GP) and the hospital. The GP, as the first person people often see, assesses the symptoms the patient describes. If the GP suspects the person has Parkinson’s disease they should be referred quickly. Before treatment is started, they should see a specialist with expertise in the other possible diagnoses (NICE- National Institute for Health and Care Excellence guidelines 2006).
GPs act as ‘gatekeepers’ making sure that the hospital is not flooded with requests from people who are worried about symptoms or having conditions which do not need hospital management. On the whole this system works well. The GP will assess the symptoms that are being presented, and decide when to refer to a specialist and when to wait to see if the symptom goes away by itself. Sometimes a symptom does not immediately suggest a definite diagnosis or require urgent treatment so the GP may wait for more symptoms to appear which may point more clearly in the direction of one diagnosis rather than another.
 
The experiences of people who have Parkinson’s disease suggest it can be very hard to diagnose, especially if the early symptoms are not the typical ones of tremor, slowness of movement and muscular rigidity. Many of the more subtle symptoms which are not specific to Parkinson’s disease may be present for months or years and can only be seen as early signs later, when looking back. The gradual start of symptoms can make it very difficult for a GP to make an early diagnosis, because there are no specific tests for Parkinson’s disease. This sometimes meant several years of vaguely worrying symptoms which doctors may not have been certain of the cause of or may have misinterpreted. Although this can lead to anxiety and frustration, there is no evidence that any current treatment slows the progression of the disease, even though treatment can relieve many of the troublesome symptoms.
Both the GP and the first consultant she saw had told Jean that she had nothing wrong with her. She saw several GPs in her practice over many months which meant that the cumulative, progressive nature of her symptoms was not recognised. After a year, she arranged a private consultation with a neurologist. Jean feels the system let her down and needlessly wasted a year of her life.
Several people we talked to were referred to a neurologist straight away after seeing their GP, but in some cases there was delay as other diagnoses were considered first.
 
Rachel had been given the diagnosis by a new doctor who didn’t know her. When he looked up her symptoms in a text book she had difficulty trusting his conclusions. Philip's GP knew him but saw him only occasionally which made it easy for the GP to recognise that his face had lost some of its usual mobility.
 
Some people felt that their GP had been slow to recognise early Parkinson’s disease. Humphrey, who had worked out that Parkinson’s was the likely diagnosis, was told by his GP that he was probably wrong as he was too young. The neurologist he later saw confirmed the diagnosis after a 5 minute discussion of his symptoms.
 
Several people returned many times to their GP, and were given treatments for such things as anaemia, frozen shoulder, repetitive strain injury, trapped nerve, ‘nerves’ or depression. Others were told there was ‘nothing’ wrong or that whatever it was would get better. Though Joe was referred to a neurologist he thinks his GP was actually very surprised to learn he had Parkinson’s. Gaynor became increasingly convinced that she did not have a frozen shoulder though several GPs insisted that she did. She finally consulted a GP she had been told had a special interest in neurology and he confirmed her suspicions. Eddie suggested to a locum GP that his tremor might be caused by PD but she didn’t think so and the diagnosis was not recognised until he saw his own doctor.
 
Waiting for an appointment was an anxious time. Some people hadn't been told why they were being referred, and they were imagining all sorts of seriously illnesses, multiple sclerosis, brain tumour, or motor neurone disease. GPs might not want to tell a patient about their suspicions in case they worry their patient unnecessarily and might prefer to wait for the consultant to confirm the diagnosis? David said that the GP he consulted about his repeated falls tested his co-ordination and took 10 seconds to make up his mind and then tell him he might have ‘a brain tumour or a lesion’. This was obviously a mistake and his GP might have done better to have said nothing.
 
The wait to see an NHS consultant neurologist was often long for the people we interviewed in 2008. Understandably the offer of an appointment in 3-6 months caused unbearable anxiety and several people decided to ask for a private referral. When David was told an appointment would take 16 weeks his family clubbed together to pay for a private consultation. Rafa was told there could be a six months wait and since he had recently watched a friend die from a brain tumour and worried that this might be causing his symptoms, he decided to go privately. Current NHS guidelines are that all patients with suspected Parkinson’s disease should be seen within six weeks. If the GP suspects a brain tumour or the later stages of Parkinson’s disease as a cause of symptoms the patient should be seen within two weeks of referral.
Most of the people who consulted a neurologist privately had been accepted back as NHS patients by the consultant they had seen.
 
After taking a careful history the neurological specialist does a detailed clinical examination which can involve examining gait, stance, and finger and hand control movement. There are no laboratory tests or other screening methods which can confirm the diagnosis of Parkinson’s disease. However many of the people interviewed had been given blood tests. Penny's thyroid function was tested because she was complaining of exhaustion, other blood tests had been used to check on general health and sometimes to rule out other conditions that could be causing their symptoms.
Many people had had an MRI scan but most of them understood that this was not to diagnose Parkinson’s disease but to exclude other conditions such as brain tumours. Only Rafa who lives in Scotland was given a brain scan known as a SPECT or DaTSCAN which was able to confirm that the area of the brain known as the corpus striatum, which produces dopamine, was not functioning properly and so confirmed the diagnosis of Parkinson’s disease. SPECT or DaTScans are not performed routinely but are carried out if there is doubt about the diagnosis to help rule out other causes of symptoms. However, the scan is not straightforward to interpret and assessment of symptoms and response to treatment may be as effective in reaching a diagnosis.
One method sometimes used to confirm the diagnosis of Parkinson’s disease is the therapeutic trial. A drug is used which will relieve the symptoms of PD but will not affect other conditions such as familial tremor with which it may have been confused. This method was used in several of the people interviewed. Particularly, it seemed, those with very early-onset Parkinson’s disease like Tom, Karen and Helen. The drug used is dopamine, although once the diagnosis has been made and even though it may have dramatically relieved symptoms, it is usually not continued, especially in young-onset PD patients (see Managing medication for Parkinson's disease).
Sometimes consultant neurologists cannot give a confident diagnosis the first time round. They have also been known to make a wrong diagnosis.

Last reviewed May 2017
Last updated May 2017

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