My Parkinson’s was diagnosed four years ago but I was attending my doctor for two years before that. Is it difficult to diagnose?
The diagnosis of Parkinson’s can be difficult and it is very common for people to realize, after the diagnosis has been made, that the symptoms have been there for longer than was first thought.
These earlier symptoms could have led to your visits to the doctor, especially as some of them are rather vague and easily attributable to getting older, or to being a bit depressed, or they may have an arthritic flavour to them. The cause of a tremor can be difficult to diagnose as there is a common variety of tremor known as familial or essential tremor (see the next question for more information about this) which can be confused with Parkinson’s.
As there is no laboratory test for Parkinson’s, a doctor may not be able to be sure about the diagnosis until time passes and a change in the overall picture makes the Parkinson’s more obvious or rules it out. Most doctors will not want to say it is Parkinson’s until they are sure. This will usually be when at least two of the three main symptoms (tremor, slowness of movement and stiffness) are present.
What are the other medical conditions that sometimes get confused with Parkinson’s?
There are several conditions that may need to be considered by your doctors.
• Essential tremor (otherwise known as familial or senile tremor) is a common cause of diagnostic confusion.
Usually an essential tremor has been there, even if in a milder form, for many years and, in over half the cases, there is known to be a tremor in the family. By contrast, finding another member of the family with Parkinson’s is rare. An essential tremor becomes worse with anxiety and rather better with small amounts of alcohol. Essential tremor is at its worst with the arms outstretched or when you are holding a cup of tea or writing, whereas the tremor of Parkinson’s is usually most obvious when the arm is doing nothing and at rest (which is why it is sometimes described as a resting tremor). The tremor of Parkinson’s is also quite often on one side. However, there are
exceptions that make diagnosis difficult, particularly when the tremor appears to have come on recently but looks like an essential tremor. It is at this stage that the diagnostic skills of a specialist can be helpful, but a totally confident diagnosis may still not be possible at the first consultation.
The Tremor Foundation can provide information support on essential tremor (see Appendix 1 for contact details)
• A shuffling gait (looking rather like the one sometimes seen in Parkinson’s) can occur in elderly people who are known to have had a stroke or high blood pressure. It is caused by hardening of the arteries rather than by Parkinson’s. In such cases other symptoms that are often found in Parkinson’s (such as tremor, stiffness and lack of
coordination of movements other than walking) are usually absent.
• Some drugs can cause side effects that resemble Parkinson’s. However, this form of Parkinson’s will get better when the drugs are stopped, although the
improvement may take many months. (There is a question about drug-induced Parkinson’s in Chapter 1.) See the PDS information sheet on Drug-induced Parkinsonism (FS38) for more information.
• There are some rare conditions which begin by looking like Parkinson’s but which then turn out to be untypical and
which are harder to treat. These include multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and cortical basal degeneration (CBD). The PDS helps people with these conditions. In addition, the Sarah Matheson Trust supports people with MSA, and the Progressive Supranuclear Palsy (Europe) Association supports people with PSP and CBD. All these organizations also support research into these conditions (see Appendix 1 for contact details). See the PDS information sheet on Parkinsonism (FS14) for more information.
I know Parkinson’s is something to do with the brain and I thought the doctor at the hospital would send me for a brain scan but she didn’t. Why not?
The substantia nigra (the part of the brain affected in Parkinson’s) is very small and cannot be seen on the type of brain scans that are available at the moment. The two usual types of scan, CT and MRI, look normal in someone with Parkinson’s.
Such scans are therefore only used when the doctor has a serious worry that it could be another condition such as a brain tumour, a blockage of the system that drains the fluid in the brain, or a stroke. As these concerns are rare, for most people a brain scan is not necessary.
Two other kinds of scan, PET (Positron Emission raphy) and SPECT (Single Photon Emission Computed Tomog-raphy), which use radioactive labels, are currently being used by researchers, and can show the loss of dopamine activity, characteristic of Parkinson’s but which can also be caused by other types of parkinsonism. However, PET and SPECT cannot be reliably used to differentiate the different types of parkinsonism from each other. The SPECT scan, also called DaTSCAN, has been developed and is usually used to separate essential tremor (see previous question) from other kinds of tremulous parkinsonism, in the few cases where the diagnosis cannot be made using clinical observation and medical history alone.
My friend has recently been told he has Parkinson’s and he was sent up to a special clinic in London to have his tremor measured. What good will that do?
Your friend has probably been asked to go to the clinic as part of a research study to measure his tremor more accurately than a doctor can do in an ordinary clinic. Such careful measurements contribute to our understanding of Parkinson’s and other neurological conditions, but they are not necessary for the diagnosis of Parkinson’s. Your friend may, however, derive overall benefit from seeing doctors with a special interest in Parkinson’s.
What should I do? My doctor says that I have Parkinson’s but my friends don’t believe it and really I don’t either.
All doctors accept that their patients could be correct in this situation, particularly when there is no special test. The thing to do would be to go back to your GP and ask him or her how sure they are about the diagnosis. Parkinson’s can usually be diagnosed only with reasonable certainty when two of the three main symptoms are present (see the next question for more information about them). If it is a problem of tremor with no other symptoms or physical signs, your GP may accept that the diagnosis cannot be substantiated with confidence. By the end of the discussion you may both have decided that it would be worthwhile to get the opinion of a specialist. If you have already seen a specialist and still do not believe or accept the diagnosis, you could ask for a second opinion. If your GP and one or two specialists all agree that it is Parkinson’s, you should probably accept that your friends might be wrong! An alternative is to press for a DaTSCAN.