Blood tests

Blood tests can help doctors find the causes of some diseases or health problems. But, in almost all cases, there are no specific blood tests that can tell us exactly what the causes of chronic pain are, even if the pain has been present for many years.

There is an exception, and this is a blood test specific to a disease called ankylosing spondylitis. This is a rare cause of chronic pain and stiffness in the neck and back, especially the lower back area.

However, there are no blood tests for a chronic pain condition such as fibromyalgia syndrome or FMS (see Useful Information for more details on fibromyalgia). The doctor or specialist will make the diagnosis based on your symptoms and a physical examination.

Most people do not need blood tests because the doctor and/or physiotherapist can work from the history of your symptoms and the results of clinical examinations. So it’s quite possible that you won’t need any blood tests at all.

If you do have a test, you will be told that the result is either positive or negative:

A positive result may mean that:

•   Further tests are needed. For example, if anaemia is present, then you may require further blood tests to determine the type of anaemia.

•   No further blood tests are required.

•   You need further investigation, like a CT scan or bone scan (see p. 57).

A negative result may mean that:

•   You do not have the problem that has been tested for. The part of the body that the test checked is working normally. This is the good news.

•   There are currently no blood tests that give a clear understanding of the reasons for the pain.

•   The problems are functioning within pain system (see Chapter 2). In chronic pain, blood tests are often negative for this reason.

Here are some questions that you may want to ask your doctor:

•   Do I need a blood test?

•   If so, what is the test checking for?

•   What does a negative result mean?

•   What does a positive result mean?

•   Could this help explain some of the reasons for my chronic pain?

Write down the answers in your notebook if possible.

X-rays and scans

Your doctor or specialist may recommend an x-ray, a bone scan, a CT scan or an MRI scan. There are difficulties about all these investigations because they do not always show clear, understandable reasons for the pain problem.

This may cause you to feel angry, worried and confused. However, it may help if you get more information by asking your doctor, or the specialist who ordered the test, some of these questions:

•   What investigations are helpful for chronic pain?

•   What do positive findings mean?

•   What do negative findings mean?

Again, write the answers in your notebook if you can.

WHAT CAN X-RAYS TELL US?

X-rays of different parts of the body, such as the knee joint, back or neck, show bones, and their size, shape, surface, density and relationship to other bones and joints. This means that x-rays tell us about fractures, dislocations, and abnormally shaped bones. The term ‘congenital’ may be used to describe the way your bones or joints were originally formed before you were born.

X-rays can also show normal changes in the bone size, shape and joints which are related to growing older. Doctors, nurses, radiographers and physiotherapists may use many different terms for these normal, ageing changes, including spondylosis, old age, wear and tear, arthritis and osteoarthritis. Reports from radiologists may include comments about the bone size, shape of the joint, and the gap between the bones.

X-rays do not clearly show soft tissues like muscles, ligaments, tendons, nerves, discs and cartilage and do not show pain.

If you have an x-ray, you will be told that the result is normal, positive or negative:

DO I NEED AN X-RAY?

There are guidelines from the Royal College of Radiologists about which x-rays are the most helpful for which problems or symptoms. For example, the radiation dose in a CT scan is equal to 500 chest x-rays. Doctors use these guidelines, along with a history of symptoms and the results of clinical examinations, in order to decide whether or not a scan may help find any specific factors or causes for the pain. Doctors want to be sure that scans are going to be useful because they don’t wish to expose people to increased levels of radiation from unnecessarily high numbers of x-rays or scans.

Doctors do not request x-rays of the spine very often. This is because spinal x-rays do not give much information about the reasons for chronic pain. They are useful when you have had an accident, to ensure that no fracture or dislocation has occurred. They are also helpful when symptoms, including pain, suggest infection or inflammation.

Scans

An MRI scan shows all the structures of the body very clearly. It shows skin, bones, soft tissues (including discs, large nerves, muscles, joints, cartilage, ligaments, blood vessels) and organs such as the heart, stomach, etc. It shows how parts of the body are changing because of age or disease. Repeated MRI scans can also show the speed of changes in the body tissues. These scans are taken at different angles, and sections through the body, to give a series of views. An MRI scan has no risk of radiation doses unlike CT Scans.

A CT scan also shows all the structures of the body clearly and is available in many places. It is used for specific problems in the brain, especially after head injury or strokes. CT scans are used when MRI scans are not available or for very specific assessment of spinal problems with myelography. On the whole, MRI scans are used, as they have less radiation risk. An MRI scan is the first-choice investigation for spinal cord symptoms or for chronic or persisting spinal pain problems.

A positive MRI or CT scan result may indicate that there is damage or pressure on nerve fibres.

A negative result can be helpful because it tells you that the structures scanned are normal. However, it does not tell you why you still have persistent or chronic pain. A negative result also means that it will do no harm to gradually increase physical activity despite pain. Chronic pain does not mean that you will harm or damage the pain areas or body tissues if you gradually increase your activities (see Chapters 8 and 9 for more on pacing skills and getting fitter).

BONE SCANS

There are two types of bone scan, a bone densitometry scan and an isotope bone scan.

A bone densitometry (or DEXA) scan finds out how dense your hip, wrist and spine bones are. The doctor will only request this test if you have significant risk factors for osteoporosis (see Useful Information for more on osteoporosis). Some of these factors are:

•   An early (under 45) menopause

•   Prolonged bed rest

•   Being a smoker

•   Having taken daily steroid drugs for many months or years

If you have no osteoporosis risk factors, there is no need to have this type of scan. If you are uncertain about whether or not a bone densitometry scan would be helpful in your case, talk to your doctor.

An isotope bone scan shows whether or not there is inflammation or increased bone cell activity. It helps find bone tumours that can occur within the bone tissue. It also helps find tumours that have spread from a cancer problem elsewhere in the body, e.g. from the lung, breast or kidney.