How is multiple sclerosis diagnosed?
Multiple sclerosis is a complex and unpredictable disease. There is no single test, symptom, or physical finding which confirms a person has the disease. Some multiple sclerosis symptoms can also be caused by other diseases.
A diagnosis must be made by going through a careful process, making sure the findings are consistent with multiple sclerosis and ruling out other causes.
What should I do if I think I have multiple sclerosis?
If you're concerned you have multiple sclerosis symptoms please see your GP in the first instance. They may refer you to a Neurologist if they believe further tests are necessary. Remember, you can seek support from health professionals before, during and after a diagnosis.
Criteria for a diagnosis
While there is no exact formula, the basic "rule" for a diagnosis has two criteria:
- There must have been two attacks at least one month apart. An attack, also known as an exacerbation, flare, or relapse, is a sudden appearance or worsening of one or more multiple sclerosis symptoms, lasting at least 24 hours.
- There must be more than one area of damage to the sheath that protects your nerves, called myelin. These are the scars or ‘sclerosis’ caused by the disease. The damage to myelin must have occurred at more than one point in time. It’s also important to ensure the damage hasn’t been caused by another disease.
MRI (magnetic resonance imaging)
MRI is the preferred method used to detect lesions (also known as scarring or damage) caused by multiple sclerosis in the central nervous system (made up of the brain, the optic nerves and the spinal cord).
A multiple sclerosis diagnosis may not always be made solely on the basis of MRI.
There are other diseases that cause lesions in the central nervous system that look like those caused by multiple sclerosis. There are also lesions found in healthy people, particularly in older people, that are not related to any ongoing disease.
A normal MRI doesn’t absolutely rule out multiple sclerosis either. Sometimes your medical history and the results of other clinical testing can indicate multiple sclerosis. There are many factors that create a clear diagnosis.
Clinical examination
Other symptoms of multiple sclerosis are evaluated during a clinical exam from a physician. This covers an extensive review of mental, emotional and language functions, movement and coordination, vision, balance and the functions of the five senses. The person’s history is also taken into consideration.
Sometimes other tests are needed
It’s not usually necessary to do all diagnostic tests for every person. Sometimes if a clear-cut diagnosis can’t be made based on MRI and clinical exams, additional tests may be ordered. These include:
- electrical diagnostic studies which can show if there is a slowing of messages in the various parts of the brain
- cerebrospinal fluid studies which test for the presence of oligoclonal bands, indicating an abnormal autoimmune response (these are present in other diseases as well so they can’t be used as positive proof of multiple sclerosis)
- blood tests which may rule out other causes for various neurological symptoms.