Multiple Sclerosis - Diagnosis
Sometimes a doctor can make a reliable diagnosis of MS fairly easily and quickly. The distribution of symptoms is important since MS affects many different areas of the body over a period of time. The pattern of symptoms is also important. A case of relapsing-remitting MS can often be diagnosed because of the way the symptoms come and go.
Since the symptoms of MS are similar to those of other diseases, diagnosis can often be difficult and complicated. Many tests and extended observation may be necessary to decide what is causing the patient's symptoms.
The usual medical procedures used to make a diagnosis include a medical history, a standard neurological (nervous system) examination, and several laboratory tests. Among the tests most commonly used to confirm or rule out a diagnosis of MS are:
- Magnetic resonance imaging (MRI) can show plaques on the brain and spinal cord. But plaques are present with other disorders as well. For example, the plaques caused by MS are sometimes difficult to distinguish from those caused by strokes (see stroke entry) or the simple process of aging.
- A lumbar puncture (spinal tap) is a process in which cerebrospinal fluid (CSF) is removed from the patient's spine with a long, thin needle. The CSF is then studied. The presence of white blood cells and other substances may be a clue to the presence of MS.
- Evoked potential tests (EPT) are tests that measure how quickly an electrical current passes through neurons. Scientists know the normal rate at which currents pass. If they move more slowly than normal, plaques may be present. An EPT can be conducted in various ways. One method is to apply a small electrical charge to the skin. A light can also be shined into a person's eyes. Or a tone can be sounded near his or her ears.
The neurologist (nerve specialist) conducting these tests may decide the patient is in one of three categories: "definite MS," "probable MS," or "possible MS." These three categories represent decreasing confidence in the accuracy of the diagnosis.