Clinically isolated syndrome (CIS)
In the years before they’re diagnosed with MS, it’s possible that some people may get a diagnosis of one of two syndromes. These are clinically isolated syndrome (CIS) and radiologically isolated syndrome (RIS).
Lots of people are diagnosed with these and never go on to get MS. But for some they’re an early sign that they’ll later develop MS.
Clinically isolated syndrome (CIS) and MS
You can be diagnosed with clinically isolated syndrome (CIS) if:
- you’ve had one occasion when you had symptoms like the ones people with MS get
- an MRI scan shows damage in your brain or spinal cord that’s like MS
Usually the MRI scan will show damage in the shape of lesions. But it is possible to have CIS and have a scan that looks normal.
CIS can be an early sign of MS. If people go on to have further symptoms, they get diagnosed with MS. But some people diagnosed with CIS don’t ever get symptoms again, so never get an MS diagnosis.
If an MRI scan shows damage that looks like MS, but you haven’t noticed any MS-like symptoms, you can be diagnosed with radiologically isolated syndrome (RIS) instead.
What does clinically isolated syndrome mean?
- ‘Clinically’ means you have symptoms that a doctor can notice. With CIS these are very like MS symptoms
- ‘Isolated’ means these symptoms have, so far, only happened once.
- A ‘syndrome’ is a collection of symptoms or signs that something’s not right in your body.
What are the symptoms of CIS?
- The most common symptom is when inflammation in your spinal cord causes pain or strange feelings in your arms or legs, or makes them weak.
- The second most common is optic neuritis. This is when the main nerve in your eye gets inflamed. Usually this affects your sight in one eye for a few weeks.
- CIS symptoms are like the ones people get with MS. And just like MS, they can affect almost any part of the body. They can range from being very mild to quite disabling.
- CIS symptoms come on over a few days or weeks, then usually go away. To be classed as CIS symptoms, they must last for over 24 hours. They must be caused by inflammation to the nerves or damage to the myelin around them. And these symptoms must only happen once.
How is CIS diagnosed?
Only a neurologist (a nerve specialist) can diagnose CIS. There’s no one test for CIS, so first they’ll run tests that rule out other possible causes for your symptoms, like an infection. You’ll have an MRI scan of your brain or spinal cord. The doctor will test your reflexes, balance, how you move, your eyesight and other senses. They’ll also give you a lumbar puncture, to collect and test fluid from around your spinal cord.
MRI scans can show if there’s damage to your brain or spinal cord. These are areas of inflammation and damage to the myelin around the nerves. Myelin is the fatty covering around nerves that protects them and helps signals pass along them. When it’s damaged, it causes MS-like symptoms.
You can be diagnosed with CIS if:
- you’ve had only one occasion of symptoms typical of MS
- an MRI scan shows damage that looks like the damage you see with MS
Usually there are lesions on the MRI scan, but not always.
What’s the difference between CIS and MS?
The main difference is to do with how many times you’ve had symptoms.
With CIS you can have signs on your MRI scan of damage (a lesion) in one or more parts of your brain or spinal cord. This damage hasn’t happened at different times. So you’ve only ever had MS-like symptoms once.
With MS you have lesions in two or more parts of your brain or spinal cord. This damage has happened at different times. So you’ve had symptoms more than once.
In 2017 doctors changed how they diagnosed MS. Since then fewer people get a diagnosis of CIS. Instead more people get diagnosed with MS earlier. One change was to do with old lesions on someone’s MRI scan. If this person had had only one occasion of MS-like symptoms, but doctors can see older lesions, these can be used to make a diagnosis of MS.
The other change was to do with whether your neurologist finds certain signs in the fluid around your spine. If you have a test called a lumbar puncture, and in this fluid they find oligoclonal bands, that’s a sign your immune system has been active there. This only happens in people who have MS. So if they find these bands, this helps a neurologist diagnose MS, instead of CIS. An oligoclonal band is a type of protein (called immunoglobulin).
If I have CIS, does it mean I now have MS, or will get it later?
If you’re told you have CIS, it’s because, for the time being, you don’t meet all the tests for a diagnosis of MS.
CIS is a one-off event. But doctors now see CIS as an early part of MS for many people. If the symptoms happen again, this will lead straight to a diagnosis of MS. That said, for many people their CIS won’t lead to MS. Only time will tell.
Once you've been diagnosed with CIS, your neurologist should plan regular reviews with you to check it's not become MS. They should talk over with you when these happen, for example, once a year. When you get your CIS diagnosis, you should be given information about it, and told who to contact for advice if your existing symptoms change or you get new ones.
If doctors see on your scans certain types of lesions common with MS, your chances of developing MS are higher. Around 60% to up to 85% of these people get MS in the years to come. If you have few or no lesions on your scans, then your risk of MS is much lower, at about 20%.
You’re also at higher risk of going from CIS to MS if you have:
- a bigger number of lesions on your MRI scans
- any lesions on your spine
- low levels of vitamin D
- symptoms in different parts of your body
- or if a lumbar puncture finds oligoclonal bands in the fluid around your spinal cord
It’s also more likely if you’re:
- from an ethnic background that’s not white
- a smoker (not smoking might lower your risk of CIS leading to MS).
Your risk of getting MS is much lower if scans show few or no lesions, and a lumbar puncture finds no oligoclonal bands.
If you’re at high risk of getting MS after CIS, there’s a treatment that can delay this.
Are there treatments for CIS?
Most people get over their CIS symptoms on their own, with no need for treatment. A short course of steroids can help if symptoms are especially bad, like if your eyesight is affected. They dampen down the inflammation that happens when your immune system attacks your nerves.
Steroids speed up your recovery by a couple of weeks. Whether you take them or not, your long-term recovery will be just as good. Steroids also don’t seem to make a difference to whether you develop MS in the longer term.
After you’ve had CIS, you’ll be diagnosed with MS if something similar happens again. To delay this, you can take a disease modifying therapy (DMT). You’ll be offered this only if your scans show you’re at a higher risk of getting MS. And you must keep taking it long term.
The DMTs you can take are glatiramer acetate (its brand names are Copaxone or Brabio), or one of the beta interferons. You inject these under your skin using an injector pen or a pre-filled syringe.
Radiologically isolated syndrome (RIS) and MS
You might be diagnosed with radiologically isolated syndrome (RIS) if an MRI scan of your brain or spinal cord shows damage that looks like MS, but you haven’t noticed any MS-like symptoms.
Lots of people are diagnosed with RIS and never get MS. But for some it’s an early sign that they’ll go on to develop MS.
But what if a scan shows damage that’s typical of MS and you also get a one-off occasion of symptoms like MS? Then you’ll be diagnosed with clinically isolated syndrome (CIS) instead.
What does radiologically isolated syndrome mean?
- ‘Radiologically’ means doctors can see signs that something is wrong on an MRI scan.
- ‘Isolated’ means what has happened is, so far, a one-off event.
- A ‘syndrome’ is a collection of signs or symptoms that something’s not right in your body.
When is RIS diagnosed?
RIS is usually spotted when someone has a scan of their brain or spinal cord for something unrelated to MS. This could be something like an injury or headaches.
How is RIS diagnosed?
Only a neurologist (a nerve specialist) can diagnose RIS. On your scan they see signs of damage to your brain or spinal cord called a lesion. This is an area of inflammation and damage to the myelin around the nerves. Myelin is the fatty covering around nerves that protects them and helps signals pass along them.
These lesions look very much like what neurologists see on scans of people with MS. The difference is that with RIS you don’t get any obvious MS-like symptoms. That said, there might be subtle signs that something is wrong. When doctors look closely, they see that about 1 in 3 people with RIS show signs that their memory, thinking or concentration are affected in a mild way. Sometimes anxiety and depression might be a sign of RIS, too.
Will RIS lead to a diagnosis of MS?
A lot of people with RIS never go on to be diagnosed with MS. But in one study around half of those with RIS were diagnosed with some type of MS within ten years. There’s no agreed treatment yet to stop RIS leading to MS, or to delay this.
Some things make it more likely that RIS will lead to someone’s first MS-like symptoms (called a clinically isolated syndrome (CIS).
- being younger when you’re diagnosed with RIS
- having lesions on your spinal cord
- if fluid around your spinal cord is tested and the test finds oligoclonal bands
An oligoclonal band is a type of protein (called immunoglobulin). If a test (called a lumbar puncture) of the fluid around your spine finds these bands, it’s a sign that your immune system has been active in your brain or spinal cord. This only happens with MS. If you have RIS which then leads to CIS, chances are very high that you’ll then be diagnosed with MS within a couple of years.
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