Clinically isolated syndrome (CIS)

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 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 is clinically isolated syndrome (CIS)?

• ‘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.

Clinically isolated syndrome causes

Like MS, CIS happens when your immune system attacks nerves in your brain or spinal cord. This causes inflammation and nerve damage. The fatty covering around the nerves (myelin) gets stripped away. Without this protection messages travel less easily along nerves, causing your symptoms.

What are the symptoms of CIS?

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.

Some common CIS symptoms are:

Pain and unusual sensations

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.

Optic neuritis

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.

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.

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:

• younger
• female
• 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.

MS 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.