Understanding Multiple Sclerosis
Most patients first seek medical help after an initial attack of symptoms called a clinically isolated syndrome (CIS). Not all patients who have a CIS go on to develop MS, and it is difficult to predict which patients will or will not.
Multiple sclerosis can be challenging to diagnose as there is no one test for it, and a number of other conditions may mimic its symptoms. To confirm a diagnosis of multiple sclerosis the doctor needs to find:
- Evidence of nerve damage in at least two different areas of the central nervous system (brain, spinal cord, and optic nerves)
- Evidence that the damage occurred in episodes that happened at least one month apart
- No evidence that the damage is caused by other conditions
A diagnosis of multiple sclerosis is based on results from a combination of various tests. These include the patient’s medical history, neurological exam, magnetic resonance imaging (MRI) scans, evoked potential tests, and possibly a spinal fluid test.
The doctor will ask about the patient’s personal and family medical history, including lifestyle factors, prescription or other drug use, and other medical conditions that the patient or relatives may have had. The doctor will ask the patient to describe the symptoms experienced, when they occurred, and how long they lasted.
In a neurological exam, the doctor will test the patient’s vision and reflexes and evaluate balance, coordination, and muscle strength.
Evoked Potential (EP) Tests
This is a simple and painless electrical test of nerve function that assesses how long it takes nerve impulses from the eye, ear, or skin to reach the brain. It involves having electrodes placed on the scalp over specific areas of the brain that process sensory information. Evoked potential tests can be used to evaluate nerve transmission for vision, sound, or muscle responses in the legs or arms.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) scans are important diagnostic tools in MS and are used for diagnosing multiple sclerosis, tracking changes over time, and helping to determine treatment effectiveness.
Click the icon to see an image of a brain MRI.
MRIs scans can detect bright patches that indicate areas of damaged myelin and injured tissue (lesions) caused by MS. However, about 5% of people who are confirmed to have multiple sclerosis based on other diagnostic criteria, do not show evidence of lesions in an initial MRI.
Once diagnosed, periodic follow-up MRIs can be used to track the disease and effectiveness of treatments in two ways:
- By distinguishing new lesions from old ones
- Revealing increasing or decreasing numbers of lesions within the central nervous system over time
Cerebrospinal Fluid Analysis
A spinal fluid test by itself cannot confirm or exclude multiple sclerosis but it can be useful when combined with other tests. Obtaining a sample of spinal fluid requires a lumbar puncture (also called spinal tap). Spinal fluid in patients with MS usually contains unusually high levels of immunoglobulin G (IgG) antibodies as well as other proteins and fragments of myelin. These can be signs of an autoimmune disorder, but not necessarily multiple sclerosis.A lumbar puncture, or spinal tap, is a procedure to collect cerebrospinal fluid to check for the presence of disease or injury. A spinal needle is inserted, usually between the 3rd and 4th lumbar vertebrae in the lower spine. Once the needle is properly positioned in the subarachnoid space (the space between the spinal cord and its covering, the meninges), pressures can be measured and fluid can be collected for testing.
Ruling Out Other Disorders
The symptoms of MS overlap with a number of other diseases that must be ruled out. These conditions include stroke, alcoholism, emotional disorders, Lyme disease, chronic fatigue syndrome, fibromyalgia, AIDS, cervical spondylosis, certain neurologic degenerative illnesses, transverse myelitis, and certain other autoimmune disorders (hypothyroidism, scleroderma, Sjogren syndrome, vasculitis, and systemic lupus erythematosus).