How is MS diagnosed?

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When a person has symptoms that are similar to the symptoms of MS, a neurologist – a specialist who treats diseases of the brain, spinal cord and nerves – will need to collect a detailed medical history, order a range of tests, and perform a physical examination to check certain reflexes and responses. This information is then used to determine what is happening within the central nervous system, what may have happened in the past, and whether a person meets the international criteria for a diagnosis of MS. This involves excluding any other possible causes for the symptoms the person is experiencing. If the results do not meet the criteria for a definitive diagnosis of MS, a doctor may diagnose clinically isolated syndrome or they may not be able to make a definite diagnosis.  For some people it takes many years to be given a diagnosis and they may need to be monitored for a while; however, for others, a diagnosis is given when they first experience symptoms. In some instances there may even be enough information for a doctor to identify a particular type of MS.  It is important to remember the process is different for everyone.

International diagnostic criteria

The criteria used to diagnose MS are agreed upon by an international committee of experts. The criteria specify the evidence a doctor needs to make a diagnosis of MS. The most important detail required is evidence of lesions in different parts of the central nervous system, at different times, with no alternative explanation other than MS. The criteria are updated regularly as better technology becomes available and as researchers learn more about MS. Today, an accurate diagnosis of MS can be achieved much quicker than it was in the past.

Medical history

Once diagnosed with MS, many people realise their symptoms actually started many years before. That is why medical history is important. A person’s neurologist will usually ask about
any symptoms experienced in the past. Some of the symptoms might be evidence of existing lesions and lesions in different parts of the central nervous system. People are sometimes doubtful about telling their neurologist about symptoms, particularly unusual ones like tingling sensations or dizziness. It is important to remember neurologists are specialists who understand the central nervous system and the unusual symptoms it can produce.

Magnetic resonance imaging (MRI)

MRI scans are a specific type of diagnostic imaging used to produce images of the brain
or spinal cord. On the scans, areas of damage may show up as spots known as lesions. If
there are lesions, your neurologist will examine what type of lesions they are as well as their location. More than one lesion might be evidence of lesions in other parts of the central nervous system. Different types of MRI scans can also be used to provide different types of information. Some MRI scans can show older lesions which are remyelinating, or areas where scarring has occurred at a different time.

Blood tests

Your neurologist may order a range of blood tests. Generally these will be to exclude other possible causes of your symptoms. MS cannot be diagnosed by a single blood test, but test results can contribute information to the diagnostic process. They can also provide important information your neurologist will need to prescribe treatments.

Lumbar punctures

A lumbar puncture (sometimes called a spinal tap) is a test which involves taking a small amount of fluid from your spine using a needle. The fluid is then sent to a laboratory to test for a number of things that can help the neurologist to build a picture of what is happening inside your body. One of the things your neurologist might be looking for is oligoclonal bands, which can provide evidence of inflammation occurring in the central nervous system.

Evoked potentials (EPs) and visual evoked potentials (VEPs)

Evoked potentials are tests which measure the time it takes for messages to travel along nerve fibres to the brain. If messages are delayed, it can indicate scarring to nerves even if you are not experiencing symptoms. Visual evoked potentials (VEPs) provide information about how well messages are travelling along your optic nerve. These tests measure the time between when you are shown an image to when the message registers in the part of your brain that processes information from your eyes. VEPs are one of the more common EPs used to diagnose or monitor MS. Your doctor may order other types of EPs such as somatosensory evoked potentials, which measure messages travelling from your skin, or auditory evoked potentials, which measure messages travelling from your ears.

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