Secondary Progressive Multiple Sclerosis (SPMS) is a stage of the condition that follows an initial period of relapsing remitting activity. In this phase, the disease transitions from a pattern of distinct attacks and recoveries to a more steady and gradual increase in disability over time. Clinically, this change represents a shift from a primarily inflammatory process to one dominated by neurodegeneration. While the immune system may still cause occasional flare-ups, the hallmark of SPMS is the persistent accumulation of symptoms regardless of whether new relapses occur. Understanding this transition is essential for adapting treatment plans to protect nerve function and maintain independence.
What we will discuss in this article
- The transition from Relapsing Remitting MS to SPMS
- Biological mechanisms behind the progressive phase
- Distinguishing between active and non active SPMS
- Common symptoms and how they evolve over time
- Clinical assessment tools for tracking progression
- Management strategies and modern treatment options
- Emergency guidance for sudden neurological changes
The transition from RRMS to SPMS
Most people diagnosed with Multiple Sclerosis are initially identified as having the relapsing remitting form.
Over time, often a decade or more after the initial diagnosis, the disease behaviour may change. In the earlier stages, the body is often able to repair the myelin damage caused by immune attacks, leading to periods of remission. However, in SPMS, the cumulative damage to the axons (the nerve fibres themselves) becomes more pronounced, and the body natural repair mechanisms can no longer keep pace. This leads to the gradual worsening of physical or cognitive function that characterises the progressive stage.
Biological mechanisms of progression
The shift to SPMS is driven by complex changes within the central nervous system that go beyond simple inflammation.
While the early stages are characterised by immune cells crossing from the blood into the brain, SPMS often involves smouldering inflammation that is trapped behind the blood-brain barrier. This chronic activity, along with the loss of energy support for the nerves and the accumulation of iron in the brain, contributes to the slow death of nerve fibres. In clinical terms, this is often referred to as PIRA (Progression Independent of Relapse Activity). It means that even if a person has not had a clinical relapse in years, their neurological function may still slowly decline due to these underlying biological processes.
Defining SPMS: Active versus Non active
To provide the most effective care, clinicians further categorize SPMS based on current disease activity.
Neurologists look for two specific indicators:
- Active SPMS: This occurs when a person experiences occasional relapses or when new lesions appear on an MRI scan during the progressive phase. This activity suggests that there is still a significant inflammatory component that can be targeted with specific medications.
- Non-active SPMS: In this state, there are no new relapses or MRI changes, but the person is still experiencing a slow increase in disability. Management for this type focuses more on neuroprotection, rehabilitation, and symptom control.
Identifying which subtype a person has is vital because many modern disease modifying therapies are specifically licensed only for the active form of SPMS.
Common symptoms and their evolution
The symptoms of SPMS often mirror those found in earlier stages, but they may become more persistent and less likely to resolve.
As the condition progresses, individuals may notice:
- Mobility Changes: Increased stiffness (spasticity) in the legs and changes in balance that make walking more taxing.
- Cognitive Fatigue: Difficulty with processing speed, memory, or multitasking, often referred to as brain fog.
- Bladder and Bowel Issues: Increased urgency or frequency that becomes a daily management concern.
- Neuropathic Pain: Persistent tingling, burning, or aching sensations in the limbs.
Clinical management emphasises the importance of a multidisciplinary approach, using physiotherapy, occupational therapy, and digital health tools to monitor and manage these evolving challenges.
Management and treatment options
The goal of treating SPMS is to slow down the rate of progression and manage symptoms to improve quality of life.
Disease Modifying Therapies
For those with active SPMS, specific oral and injectable medications are available that have been shown to reduce the risk of relapses and slow the accumulation of physical disability. These treatments work by targeting the specific immune cells responsible for ongoing inflammation.
Rehabilitation and Lifestyle
- Physiotherapy: Essential for managing spasticity and maintaining strength and flexibility.
- Cognitive Training: Exercises designed to improve focus and memory.
- Nutrition and Exercise: Maintaining a healthy weight and staying as active as possible can help reduce the overall burden on the nervous system.
Emergency guidance
While SPMS involves a slow progression, sudden neurological shifts still require urgent clinical evaluation.
Seek immediate medical help if you experience a sudden, total loss of vision, an acute inability to walk, or a rapid onset of confusion, as these may indicate a severe relapse or a different medical emergency.
Seek urgent medical advice if you notice:
- A sudden loss of bladder or bowel control that is new and persistent
- Signs of a severe infection, such as high fever and shivering, which can temporarily worsen MS symptoms
- Rapidly spreading weakness that moves up the body over a few hours
- Intense, sharp pain that prevents normal movement or sleep
- Symptoms of a severe systemic reaction to any ongoing medications
To summarise
Secondary Progressive Multiple Sclerosis is a phase of the disease characterised by a steady accumulation of disability following an initial relapsing period. It represents a shift from active inflammation to a more neurodegenerative process. While this transition can be challenging, modern clinical care offers various pathways for management, especially for those with the active form of the disease. By combining targeted medical treatments with dedicated rehabilitation and lifestyle adjustments, individuals can work to slow the progression and maintain their functional independence for as long as possible.
How do I know if I have transitioned to SPMS?
The transition is often recognised in hindsight. If you notice a gradual worsening of symptoms over at least six months that is not related to a specific relapse, your neurologist may discuss a change in diagnosis.
Can I go back to Relapsing Remitting MS?
No. Once the disease has entered the secondary progressive phase, the underlying biological process has changed. However, the progression can be slowed significantly with the right management.
Are there treatments for non active SPMS?
While many DMTs are for active disease, management for non active SPMS focuses on intensive rehabilitation, symptom management (like Botox for spasticity), and lifestyle interventions.
Does SPMS affect life expectancy?
Most people with SPMS have a life expectancy near that of the general population. The focus of care is on maintaining quality of life and mobility.
Why does heat make my progressive symptoms worse?
This is known as the Uhthoff phenomenon. Higher temperatures make it harder for damaged nerves to conduct signals. It is a temporary worsening, not a permanent progression.
Can exercise help with progression?
Yes. Clinical evidence shows that regular, adapted exercise can improve mobility, reduce fatigue, and may even have a neuroprotective effect on the brain.
Is cognitive decline inevitable in SPMS?
Not necessarily. While some cognitive changes are common, many people maintain excellent cognitive function throughout the progressive phase by using compensatory strategies and staying mentally active.
Authority Snapshot
This article was reviewed by Dr. Stefan Petrov, a UK trained physician with an MBBS and extensive experience in general medicine, surgery, and emergency care. Dr. Petrov has worked in intensive care environments and has a strong background in performing diagnostic and therapeutic procedures. He is dedicated to medical education and providing evidence based health content to help patients navigate complex chronic conditions like Multiple Sclerosis with clarity and confidence.
