It’s crucial to understand how doctors assess MS symptoms and how the severity of the disease increases over time. MS occurs when the body’s immune system attacks myelin. Myelin is a fatty substance that surrounds nerve fibers in the central nervous system like a sheath. Myelin acts like the protective insulation on an electrical wire. Disturbing the myelin sheath disrupts signals traveling to and from the brain. This causes the various symptoms of MS, such as weakness. Inappropriate immune system activity sometimes damages the nerves themselves, leaving scar tissue or sclerosis. This may cause permanent damage and can lead to disability.
Among other symptoms, MS may cause:
- blurred vision
- tingling and numbness
- partial or total paralysis
- speech difficulties
- hearing loss
- elimination problems
- memory and cognition difficulties
All of these symptoms are challenging to cope with. MS presents the added challenge of being a highly unpredictable condition. Symptoms vary greatly from one person to the next, frequently waxing and waning. Major symptoms may disappear entirely, only to be followed by relapse later. It can be very difficult to get a handle on the disease.
MS symptoms frequently mimic other nervous system disorders. Doctors usually conduct neurological tests to rule out other possibilities. These tests focus on checking reflexes, sensations, body movements, vision and pupil responses, and eye movements. Five types of tests are commonly used to assist with the diagnosis of the condition. These tests are described below.
Neurologic Exam and Interview
A physician gathers a detailed medical history and uses a variety of tests to evaluate cognition, emotional clues, language function, and physical abilities. Physical abilities examined include balance, coordination, vision, and other senses. Doctors often rely on the Expanded Disability Status Scale (EDSS) to measure the physical disability associated with MS. By asking a series of questions they’re able to assess where a patient may be on the MS spectrum.
Cerebral Fluid Analysis
A spinal tap (lumbar puncture) allows doctors to collect a sample of cerebrospinal fluid (CSF) and perform various tests. These tests are used to confirm a diagnosis of multiple sclerosis. They can also help rule out diseases that may mimic MS. One important test that your doctor may order is an oligoclonal band screen. The presence of oligoclonal bands suggests inflammation within the central nervous system. This is a strong indicator of MS.
Other tests may include myelin basic protein (MBP) and IgG index. The MBP test is now considered to be of little use in the diagnosis of MS. An IgG index measures proteins in CSF that indicate ongoing inflammation. IgG stands for immunoglobulin gamma. It is one of the human immune system’s major antibody types.
Magnetic resonance imaging (MRI) of the brain and spinal cord can detect lesions. These lesions signal damage from the exacerbation of MS. However, some patients who display a normal MRI may have MS. Others with lesions—particularly the elderly—may not have MS. Patients are often given a contrast medium containing a compound that includes a metallic element called gadolinium. This element makes lesions more distinct in MRI images. MS lesions detected this way are referred to as “gadolinium-enhancing lesions.” The contrast agent is given by injection into a vein. Gadolinium is not radioactive and is considered quite safe.
Evoked Potential (EP) Test
This type of assessment records the nervous system’s electrical response to stimulation across different pathways. The residual damage from MS attacks can be detected by slower neurological response times. This test can detect nerve pathways that a neurologic exam cannot.
A blood test cannot diagnose MS. However, blood tests can be used to rule out other conditions that produce similar outcomes. These other conditions include collagen vascular diseases, hereditary disorders, and HIV. Sometimes blood is drawn so doctors can compare the amounts of IgG antibodies in CSF and blood serum. The ratio of these two numbers is the IgG index. It is frequently high among people with MS.
MS is a challenging disease to diagnose. A doctor must detect damage in two separate areas of the central nervous system. These areas include the brain, spinal cord and optic nerves. They must also verify that instances of damage occurred at least one month apart. It’s also necessary to rule out all other possible diagnoses. There are specific guidelines for using diagnostic tools such as MRI and visually evoked potential (VEP) tests. These guidelines, referred to as the McDonald Criteria, were created in 2001 and updated in 2010. The aforementioned EDSS uses whole and half numbers and a ranking from one to 10 to assess the level of disability.
Disease Types and Progression
Four common types of multiple sclerosis are described below. All can vary across mild, moderate, and severe symptoms.
Relapsing-Remitting MS (RRMS)
This is the most common form of the disease. If you have RRMS, you experience clearly defined attacks of worsening neurologic function. Relapses and flare-ups occur and they’re followed by recovery periods.
Primary-Progressive MS (PPMS)
This form of MS causes steadily worsening neurologic function. However, distinct relapses or remissions do not occur. Only minor and occasional plateaus and improvements occur.
Secondary-Progressive MS (SPMS)
Some patients with relapsing-remitting MS develop secondary progressive MS. If you have SPMS, you no longer have relapses and recovery periods. The disease is characterized by a steadily worsening state. There may or may not be flare-ups, plateaus, or remissions. Many people who are diagnosed with RRMS develop SPMS down the road. It isn’t known whether recent treatments reduce progression from RRMS to SPMS.
Progressive-Relapsing MS (PRMS)
A small percentage of people with MS experience PRMS. These individuals experience steadily worsening conditions with attacks that are clearly identifiable. Some PRMS patients experience remissions or recoveries following a relapse. The disease progresses regardless.
Some MS patients also suffer from idiopathic thrombocytopenic purpura (ITP). This is an autoimmune bleeding disorder that results in abnormally low levels of platelets. These low platelet levels create a condition known as thrombocytopenia. The lack of these specialized blood cells leads to poor clotting, easy bruising, and excessive bleeding.
Unfortunately there’s no cure for MS. Treatments can help you manage the condition more effectively. Most people with MS have a normal or near-normal life expectancy.