Understanding the Stages of Multiple Sclerosis

Multiple sclerosis (MS) affects everyone differently, and there is no way to precisely predict how someone's MS will progress. That said, experts have identified four MS types to help classify and better understand the disease, and also to guide treatment. These types are sometimes referred to as stages because a person's MS may transition from one type to another.

MS occurs when a person's immune system attacks myelin (the fatty sheath that insulates nerve fibers) within their central nervous system (CNS). The CNS is composed of your brain, spinal cord, and the optic nerves of your eyes.

As a demyelinating disease—which is any condition that develops as a result of myelin damage—the transmission of nerve signals between the CNS and the rest of the body is impaired in MS. This leads to a variety of symptoms like numbness, pain, muscle weakness, and vision problems.

This article will review the four types, or stages, of MS, including how they differ in symptom presentation. You'll also learn about symptoms that may materialize in the final or advanced stages of MS.

Early Symptoms of MS

The symptoms of MS vary from person to person, but some symptoms generally occur earlier in the disease course than others.

For example, a classic early manifestation of MS is optic neuritis, which is inflammation of one of your two optic nerves. This condition causes blurry vision and pain with eye movement.

Other common, early symptoms of MS include:

• Sensory disturbances like numbness and tingling (paresthesias)
• Vertigo (a sensation of dizziness, spinning, or unsteadiness)
• Balance problems
• Vision changes (e.g., blurry or double vision or abnormal eye movements called nystagmus)
• Headache
• Fatigue
• Bladder dysfunction
• Muscle weakness or paralysis
  

Clinically Isolated Syndrome (CIS)

Clinically isolated syndrome describes a person's first episode of neurological symptoms caused by damaged myelin in the CNS. CIS is often referred to as the first stage of MS, even though it doesn't meet the MS criterion for dissemination in time (MS damage that occurs on different dates).

Symptoms of CIS last more than 24 hours, are not accompanied by fever or infection, and eventually improve or go away.

CIS is considered a monofocal episode when only one neurological symptom is present—for example, an attack of optic neuritis.

CIS is considered a multifocal episode when more than one neurological symptom is present—for example, optic neuritis along with paresthesias in the legs that are suggestive of MS.

Relapsing-Remitting MS (RRMS)

Relapsing-remitting MS (RRMS) is the initial diagnosis for most patients (85%) with MS. In RRMS, patients experience flare-ups (relapses) of new or worsening neurological symptoms followed by periods of symptom recovery, called remission.

Relapses are confirmed by detecting one or more enhancing lesions on a brain or spinal cord MRI. The symptoms of an MS flare-up or relapse last at least 24 hours and usually persist for days or weeks (sometimes months) before they improve or resolve.

As with CIS, the symptoms of an MS relapse depend on what nerve signaling pathway in the CNS is being attacked. For instance, if the myelin within the spinal cord is damaged, tingling, numbness, muscle weakness, or bladder problems may occur.

Secondary Progressive MS (SPMS)

Many patients with relapsing-remitting MS (RRMS) transition to a progressive form of the disease called secondary progressive MS (SPMS). This transition signals a shift in disease biology from one of inflammation to one of neurodegeneration, when nerve cells slowly stop working and die.

In SPMS, symptoms are the same as those in RRMS, but they gradually worsen or increase over time. That said, patients with SPMS can still experience occasional relapses and periods of symptom stability. This typical slow shift from relapses to symptom progression can make the diagnosis of SPMS challenging.

Primary Progressive MS (PPMS)

Around 15% of patients with MS only experience a progressive course from the start of their disease. They are described as having primary progressive MS (PPMS) because they experience an accumulation of disability over time.

The biology of PPMS is similar to that of SPMS—more of a smoldering, neurodegenerative process instead of an inflammatory one, which is seen in RRMS. PPMS also strikes at an older age (mid to late 30s on average) compared to RRMS and tends to more aggressively affect the spinal cord.

Spinal cord involvement results in slowly worsening leg stiffness, walking problems, and fatigue. Sexual and bladder and bowel problems may also occur.

Less commonly, PPMS manifests from primary damage to an area of the brain called the cerebellum. This may result in tremor (uncontrolled shaking) and ataxia (loss of muscle coordination).

Final Stages

In the final stages of MS, a person is severely disabled by their symptoms. They are also usually dependent on a care partner or nursing facility for their personal and medical needs.

While symptoms in the final stages of MS are similar to those in the early stages of MS, they are usually more severe, and there are more of them occurring at the same time.

Such symptoms may include:

• Bladder and bowel problems, like urinary incontinence (involuntary loss of urine) or constipation
• Pain associated with nerve damage and muscle spasms
• Problems swallowing, speaking, and breathing
• Extreme mobility limitations (e.g., bedbound or restricted to a wheelchair)
• Cognitive problems, such as memory loss and poor concentration
• Depression and emotional changes (e.g., mood swings or out-of-character episodes of anger)

Despite the debilitating nature of the above symptoms, MS is not considered a fatal disease. If MS is the cause of death, it usually stems from a complication of the disease, like a urinary tract infection (UTI) or aspiration pneumonia (lung infection caused by inhaled food particles).

Research has also found that the combination of MS with common health conditions like heart disease, diabetes, or depression increases your chances of dying at a younger age. This finding emphasizes the importance of addressing and managing all of your health needs, in addition to your MS.

Summary

MS can be classified into four different types, or stages:

• Clinically isolated syndrome (CIS)
• Relapsing-remitting MS (RRMS)
• Secondary progressive MS (SPMS)
• Primary progressive MS (PPMS)

CIS is a first-time episode of neurological symptoms and does not technically meet the criteria for a diagnosis of MS. Patients with CIS may or may not go on to develop MS.

Patients with RRMS—the most common type of MS—experience flare-ups of new or worsening neurologic symptoms that eventually improve or go away. SPMS and PPMS are characterized by slowly worsening symptoms and disability over time.

A Word From Verywell

Gaining knowledge about the different types of MS may help you or a loved one receive an early diagnosis of MS. Once diagnosed, you can focus your energy on creating a treatment plan with your neurologist that addresses your unique symptoms.

Treatment plans also usually involve taking a disease-modifying medication to slow your disease down and improve your future outlook living with MS.