How doctors diagnose multiple sclerosis

How doctors diagnose multiple sclerosis
February 23, 2014 11:28 PM

Multiple sclerosis is a disease of brain characterized by the formation of multiple plaques or lesions. In this disease there is loss of the myelin sheath surrounding the neurons as the result of which the conduction between different parts of the brain gets impaired. If you experience any symptoms that match multiple sclerosis like muscle spasms, altered sensations, poor vision, decreased learning and concentration then you should consult your general practitioner (GP). Your GP is going to start with taking history and general physical examination afterwards. If he thinks that you’re signs and symptoms are positive for MS, he’ll refer you to a neurologist for further investigations.

A diagnosis is considered positive if following criteria are fulfilled:

  • If the age of patient lies between 20-50 years, as the symptoms of MS usually appear between these ages.
  • The signs and symptoms should indicate that the person is suffering from certain disease of brain or spinal cord.
  • The MRI scans show at least 2 or more areas of lesion in brain or spinal cord.
  • Physical examination of patient gives positive finding. One such examination is asking the patient to bend his/her neck. Doing so produces a feeling as if a current is running down the spine. Moreover, the practitioner can examine the patient for his co-ordination, visual acuity, verbal skills and mental performance.
  • There must be recurrence of symptoms at least once or twice a month and the symptoms should repeat after a month or so. Or there must be worsening of condition over six months or one year.
  • The possibility for any other disease is ruled out and all the findings point in the direction of MS.

Diagnostic tests for MS

There is no single test that could positively diagnose multiple sclerosis. There are a number of conditions that have symptoms similar to multiple sclerosis so your neurologist will first try to rule out those conditions.

Diagnosis of MS becomes very difficult if the symptoms have appeared only once. MS is usually diagnosed only when there is a relapse of symptoms i.e. the symptoms come back after sometime. Your neurologist will carry out following tests and examinations:

Neurological examination

As explained earlier, MS affects brain, eyes and muscles. That’s why your neurologist will first check for any sign of weakness in the movement of your eyes, impaired co-ordination between your legs and hands, poor balance, slurred speech and abnormal reflexes. This will show if your nerves and pathways associated with those nerves are damaged or not- MS leads to damage of nerves.

Magnetic resonance imaging (MRI) scans

An MRI scan is meant for creating detailed image of your brain and spinal cord. This scan helps show if the myelin sheath covering your neurons is damaged or not. This test is very useful as 9 out 10 sufferers of MS are diagnosed on the basis of MRI scans. This procedure takes 10 to 30 minutes to complete and is completely painless.

Evoked potential test

MS is characterized by poor understanding of things and vision. This is meant to know if you’ve some impairment in seeing and understanding the things around you. Normally whenever you see something, your brain processes that information to derive a meaning out that information. This activity of brain can be shown in the form of several brain waves. Under normal circumstance, these waves follow a normal pattern. This test uses small electrodes placed on head. When the patient sees something, the activity of his brain produces several brain waves. These waves are compared with normal waves and any abnormality is noticed. This process is also painless.

Lumbar puncture

In the later stages of MS, body starts producing antibodies against its own tissues. These antibodies (also called auto antibodies) start to target body’s own tissues, brain and spinal cord cells in particular. High level of these antibodies in body fluids means that body is destroying its own tissues from within. In MS the level of these antibodies increase significantly in cerebrospinal fluid i.e. the fluid that fills our spine. Lumbar puncture is a procedure also known as spinal tab. In this procedure a needle is used to drain cerebrospinal fluid from the vertebral column (spine). This procedure might sound painful but actually this procedure is totally painless as it is carried under local anesthesia. The patient is usually awake during this process and only the area in which needle has to be pricked is numbed using medicines. A small amount of cerebrospinal fluid is collected and is tested for the presence of antibodies.

Blood tests

Blood tests are performed to obtain following objectives:

  • To confirm that the symptoms of the patient are due to MS and not due to the deficiency of certain vitamin.
  • To show the presence of antibodies in blood.
  • To differentiate between different types of MS.

Diagnosing the different types of MS

Once your neurologist has positively diagnosed you with MS, his next step would be to differentiate between different types of MS. Different types of multiple sclerosis that your neurologist would try to differentiate between would include:

  • Relapsing remitting multiple sclerosis (RRMS).
  • Primary progressive multiple sclerosis. (PPMS).
  • Secondary progressive multiple sclerosis (SPMS).

A diagnosis of relapsing multiple sclerosis (RRMS) is made on the following grounds:

  • If you’ve experienced two relapses of your symptoms in period more than 30 days apart.
  • If you’ve one relapse and magnetic resonance imaging (MRI) shows newly damaged myelin sheath or scarring of brain or spinal cord 3 months later.

A diagnosis of primary progressive multiple sclerosis (PPMS) is made if the following criteria are fulfilled:

  • If you had no previous relapse of symptoms.
  • You’ve experienced a progressive worsening of your symptoms over one year or so.
  • An MRI scan shows definite scarring of brain and spinal cord.
  • A lumbar puncture shows the presence of antibodies in cerebrospinal fluid.

A diagnosis of secondary progressive multiple sclerosis (SPMS) is made if the following criteria are fulfilled:

  • If you’ve had relapse of symptoms in past as well.
  • You’ve experienced worsening of your condition over last 6 months, with or without relapse of symptoms.
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Written by: Michal Vilímovský (EN)
Education: Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
Published: February 23, 2014 11:28 PM
Next scheduled update: February 23, 2016 11:28 PM
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