Types of MS

Relapsing-Remitting MS (RRMS)

RRMS is characterized by unpredictable relapses during which new appear or existing symptoms become more severe. These relapses can last for varying periods and there is partial or total recovery. The periods between relapses are characterized by a lack of disease progression. The disease may be inactive for months or years.

Secondary Progressive MS (SPMS)

SPMS may affect individuals who were initially diagnosed with RRMS. This is characterized by the development of progressive disability later in the course of the disease, and may include occasional relapses and minor remissions and plateaus.

Primary Progressive MS (PPMS)

PPMS is characterized by slow onset and steadily worsening symptoms, despite a lack of distinct attacks. There is an accumulation of disability, which may level off at some point or continue over months and years.

Progressing-Relapsing MS (PRMS)

PRMS may begin as a progressive disease, but may be interrupted by acute attacks (flare-ups) during subsequent years. This pattern of MS shows progression from onset, with clear acute relapses that may or may not resolve with full recovery.

The common theme now among healthcare professionals is early therapy initiation. It is believed that an early diagnosis, combined with therapy from the outset, can at the very least delay symptoms and flare-ups.

CIS and MS

When you first experience an MS relapse, it may seem like a sudden event – like getting hit by a bus. In reality, MS, like many other illnesses, is a process. To continue with our analogy of the common cold, after being exposed to a virus, you don’t develop cold symptoms right away. It typically takes a few days before you get a scratchy throat or a runny nose, and a few days more before you get a full-blown cold.

Similarly, an MS relapse can be thought of as the time when you first become aware of your illness. But the disease process had already been at work for many years. Researchers have not yet determined when MS starts. Some people are diagnosed with MS as early as childhood. It is likely that many people first develop the disease during adolescence, but it takes many years before the symptoms become severe enough for a person to pay attention to them.

When first diagnosed with MS, people often say that they remember having symptoms many years ago but they didn’t recognize the problem at the time. But eventually, the symptoms became severe or troubling enough that they went to see a doctor. For example, optic neuritis is a common early symptom of MS seen in doctor’s offices. In part, this is because the optic nerve is especially vulnerable to attack. However, in some cases it may be that optic neuritis, with its loss of vision, is so disturbing a symptom that people are more likely to report it to their doctor. It is harder to downplay than something like tingling or numbness, which may be explained away as simply a pinched nerve.

An attack of optic neuritis, nerve tingling or other MS symptom indicates to a doctor that demyelination is occurring. However, a single episode isn’t initially diagnosed as MS. It is first called a clinically isolated syndrome (CIS) suggestive of MS. Doctors may also refer to it as a monosymptomatic presentation, i.e. there is only one symptom. CIS may be thought of as an early-warning sign of the MS disease process. People with CIS have a very high risk of developing clinically-definite MS over the next few years. This is especially true if there is also evidence of inflammatory activity in the CNS, which can be seen using magnetic resonance imaging (MRI).

For example, in the Optic Neuritis Treatment Trial, about one in seven people with the symptom of optic neuritis went on to develop MS over the next five years. However, if they had optic neuritis as well as three or more inflammatory lesions on their MRI, just over 50% of them developed MS. Similarly, in the CHAMPS study, 50% of untreated people with CIS and at least two brain lesions developed clinically-definite MS within three years.

A single attack of optic neuritis isn’t sufficient for a diagnosis of MS since (as in the above example) many medical conditions can cause optic neuritis. According to the International Panel on the Diagnosis of Multiple Sclerosis, which developed the most recent criteria for diagnosing MS (called the McDonald criteria), a doctor needs evidence that repeated demyelinating events are occurring over time in different parts of the brain. So to be diagnosed, a person must have:

• At least two MS attacks at least 30 days apart and clinical evidence of two or more brain lesions occurring at different times; or
• One attack, clinical evidence of at least two lesions and MRI evidence of a lesion elsewhere in the CNS; or
• One attack, clinical evidence of one lesion and new lesions on two MRIs taken at least three months apart (or one MRI and a second relapse).

If there are no relapses but there are symptoms of MS, a diagnosis is made with a positive cerebrospinal fluid (CSF) analysis and two MRIs taken at least three months apart that show multiple lesions in different parts of the CNS. One of the MRIs may be replaced by a visual evoked potential (VEP) test (sometimes called a visual evoked response [VER] test).

Find out more about CIS - 8 Questions You Need to Ask CIS