People with multiple sclerosis may also develop:
- Muscle stiffness or spasms
- Severe weakness or paralysis, typically in the legs
- Problems with bladder, bowel or sexual function
- Cognitive problems, like forgetfulness or word finding difficulties
- Mood problems, such as depression, anxiety or mood swings
- Seizures, though very rare
There are four types of multiple sclerosis. You can think of the types as a way for your provider to describe your symptoms, instead of being four different conditions:
- Clinically isolated syndrome: When you have the first episode of symptoms suggestive of multiple sclerosis, but don’t meet criteria for having multiple sclerosis, healthcare providers often categorize it as clinically isolated syndrome. Inflammation and myelin damage cause your symptoms. Clinically isolated syndrome may develop into multiple sclerosis.
- Relapsing-remitting multiple sclerosis: This is the most common way that multiple sclerosis begins — an estimated 85% of people diagnosed with relapsing-remitting multiple sclerosis have this type. Multiple sclerosis causes flare-ups (relapses or attacks) of new or old symptoms. Periods of remission follow (when symptoms stabilize or go away).
- Secondary progressive multiple sclerosis: In many cases, relapsing-remitting multiple sclerosis eventually progresses to secondary progressive multiple sclerosis. In the secondary progressive stage of multiple sclerosis, nerve damage accumulates and symptoms gradually worsen. You may still experience some relapses or flares, but periods of remission (when symptoms stabilize or go away) are less likely to happen.
- Primary progressive multiple sclerosis: In some cases, multiple sclerosis symptoms may start off slowly and gradually worsen over time from the very beginning, without any periods of clear relapses or remission.
The cause of multiple sclerosis is unknown. It’s considered an immune mediated disease in which the body’s immune system attacks its own tissues. In the case of multiple sclerosis, this immune system malfunction destroys the fatty substance that coats and protects nerve fibers in the brain and spinal cord (myelin).
Myelin can be compared to the insulation coating on electrical wires. When the protective myelin is damaged and the nerve fiber is exposed, the messages that travel along that nerve fiber may be slowed or blocked.
It isn’t clear why multiple sclerosis develops in some people and not others. A combination of genetics and environmental factors appears to be responsible.
These factors may increase your risk of developing multiple sclerosis:
- Age. multiple sclerosis can occur at any age, but onset usually occurs around 20 and 40 years of age. However, younger and older people can be affected.
- Sex. Women are more than 2 to 3 times as likely as men are to have relapsing-remitting multiple sclerosis.
- Family history. If one of your parents or siblings has had multiple sclerosis, you are at higher risk of developing the disease.
- Certain infections. A variety of viruses have been linked to multiple sclerosis, including Epstein-Barr, the virus that causes infectious mononucleosis.
- Climate. multiple sclerosis is far more common in countries with temperate climates, including Canada, the northern United States, New Zealand, southeastern Australia and Europe. Your birth month may also affect the chances of developing multiple sclerosis, since exposure to the sun when a mother is pregnant seems to decrease later development of multiple sclerosis in these children.
- Vitamin D. Having low levels of vitamin D and low exposure to sunlight is associated with a greater risk of multiple sclerosis.
- Your genes. A gene on chromosome 6p21 has been found to be associated with multiple sclerosis.
- Obesity. An association with obesity and multiple sclerosis has been found in females. This is especially true for female childhood and adolescent obesity.
- Certain autoimmune diseases. You have a slightly higher risk of developing multiple sclerosis if you have other autoimmune disorders such as thyroid disease, pernicious anemia, psoriasis, type 1 diabetes or inflammatory bowel disease.
- Smoking. Smokers who experience an initial symptom that may signal multiple sclerosis are more likely than nonsmokers to develop a second event that confirms relapsing-remitting multiple sclerosis.
Multiple sclerosis signs and symptoms may differ greatly from person to person and over the course of the disease depending on the location of affected nerve fibers.
Common symptoms include:
- Numbness or weakness in one or more limbs that typically occurs on one side of your body at a time
- Tingling
- Electric-shock sensations that occur with certain neck movements, especially bending the neck forward (Lhermitte sign)
- Lack of coordination
- Unsteady gait or inability to walk
- Partial or complete loss of vision, usually in one eye at a time, often with pain during eye movement
- Prolonged double vision
- Blurry vision
- Vertigo
- Problems with sexual, bowel and bladder function
- Fatigue
- Slurred speech
- Cognitive problems
- Mood disturbances
There are no specific tests for multiple sclerosis. Instead, a diagnosis of multiple sclerosis often relies on ruling out other conditions that might produce similar signs and symptoms, known as a differential diagnosis.
Your doctor is likely to start with a thorough medical history and examination. Your doctor may then recommend:
- Blood tests, to help rule out other diseases with symptoms like multiple sclerosis. Tests to check for specific biomarkers associated with multiple sclerosis are currently under development and may also aid in diagnosing the disease.
- Spinal tap (lumbar puncture), in which a small sample of cerebrospinal fluid is removed from your spinal canal for laboratory analysis. This sample can show abnormalities in antibodies that are associated with multiple sclerosis. A spinal tap can also help rule out infections and other conditions with symptoms like multiple sclerosis. A new antibody test (for kappa free light chains) may be faster and less expensive than previous spinal fluid tests for multiple sclerosis.
- MRI, which can reveal areas of multiple sclerosis (lesions) on your brain, cervical and thoracic spinal cord. You may receive an intravenous injection of a contrast material to highlight lesions that indicate your disease is in an active phase.
- Evoked potential tests that record the electrical signals produced by your nervous system in response to stimuli may be done. An evoked potential test may use visual stimuli or electrical stimuli. In these tests, you watch a moving visual pattern, as short electrical impulses are applied to nerves in your legs or arms. Electrodes measure how quickly the information travels down your nerve pathways.
In most people with relapsing-remitting multiple sclerosis, the diagnosis is straightforward and based on a pattern of symptoms consistent with the disease and confirmed by brain imaging scans, such as an MRI.
Diagnosing multiple sclerosis can be more difficult in people with unusual symptoms or progressive disease. In these cases, further testing with spinal fluid analysis, evoked potentials and additional imaging may be needed.
