Multiple sclerosis: how to recognize the symptoms and which tests help with diagnosis?

Imagine temporarily losing your vision, feeling weakness on one side of your body, or experiencing disabling fatigue without an apparent explanation. For millions of people around the world, these may be some of the first signs of multiple sclerosis, an autoimmune disease that affects the brain and spinal cord. Considered the leading non-traumatic cause of neurological disability in young adults, multiple sclerosis represents a significant challenge for patients, families, and healthcare professionals. 

In recent decades, major advances in diagnosis and treatment have improved disease control and patients’ quality of life. Today, several disease-modifying therapies can reduce the frequency of relapses and slow the progression of neurological disability.

From the earliest signs to long-term monitoring, accurate diagnosis plays a fundamental role in multiple sclerosis care. In this article, you will learn about the symptoms of the disease and the advances that support more individualized care and clinical management. 

What is multiple sclerosis?

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system characterized by focal demyelination and diffuse neurodegeneration in both the white and gray matter of the brain and spinal cord. In other words, it is a condition in which the immune system attacks myelin, the protective layer that surrounds nerve fibers, impairing the transmission of nerve impulses between the brain, spinal cord, and the rest of the body (1, 2). 

When this inflammatory process occurs, areas of damage known as demyelinating plaques develop. These lesions can disrupt communication between different regions of the nervous system, leading to a wide range of symptoms such as visual disturbances, tingling, muscle weakness, balance problems, and fatigue (3). 

Multiple sclerosis is usually diagnosed between the ages of 20 and 40, although it can occur at other ages. The disease is more common in women and has a highly variable course, which may present as relapses interspersed with periods of recovery or as a gradual progression of symptoms over time. 

Is multiple sclerosis a degenerative disease?

Multiple sclerosis is not only a demyelinating disease but also a neurodegenerative disease of the central nervous system, characterized by the loss of neurons and their extensions, known as axons. Although it is often described as an inflammatory condition, that is, involving an immune response that leads to lesion formation and myelin destruction, it is now well established that progressive damage to neuronal structures also occurs in parallel (4). 

For this reason, multiple sclerosis is not considered solely an inflammatory disease. It is currently understood that inflammatory and neurodegenerative mechanisms coexist from the earliest stages of the disease. While inflammation is more closely associated with relapses and the formation of new lesions, neurodegeneration contributes to the progression of neurological disability over time (1, 5). 

This broader understanding of the disease has driven the development of new therapeutic strategies and biomarkers capable of monitoring both inflammatory activity and neuronal damage, enabling increasingly personalized patient management. 

What are the causes and risk factors of multiple sclerosis?

The exact cause of multiple sclerosis (MS) is not yet fully understood, but it is believed to result from the interaction of genetic, environmental, and immunological factors that lead the immune system to attack structures within the central nervous system (2, 6). 

Although it is not considered a hereditary disease, genetic predisposition plays an important role in its development. 

The risk of developing MS is higher among first-degree relatives of affected individuals, ranging from 2% to 4%, compared with approximately 0.1% in the general population. In addition, studies in monozygotic twins show a concordance rate of 30% to 50%, reinforcing the influence of genetic factors (6). 

To date, more than 200 genetic variants associated with disease susceptibility have been identified, with the HLA-DRB1*15:01 haplotype being the genetic risk factor most strongly linked to MS (6, 7). 

In addition to genetic predisposition, several environmental factors have been associated with an increased risk of developing the disease. 

One of the most studied is infection with the Epstein-Barr virus (EBV), which causes infectious mononucleosis. Recent evidence suggests that virtually all patients with multiple sclerosis have had prior EBV infection, supporting its possible role in triggering the autoimmune response (8). 

Other factors include higher latitudes, where MS incidence is greater, smoking, obesity, low vitamin D levels, and reduced exposure to sunlight (6, 7). 

These factors are believed to influence the immune response, contributing to disease onset in genetically susceptible individuals. 

What are the symptoms of multiple sclerosis?

Multiple sclerosis can present in very different ways among patients, since signs and symptoms depend on the location and extent of lesions in the central nervous system. While some individuals experience transient episodes with significant recovery, others may develop more persistent manifestations over time (1, 5). 

A hallmark feature of the disease is the occurrence of neurological relapses, defined as the appearance of new symptoms or the worsening of pre-existing symptoms lasting more than 24 hours, in the absence of infections or other identifiable causes (1). 

Early signs may include visual disturbances, tingling sensations, numbness, muscle weakness, balance difficulties, and severe fatigue. In many cases, especially in the early stages, these episodes may partially or completely resolve after a relapse. 

The most common manifestations can be grouped according to the affected neurological function. 

Visual symptoms: among the most frequent manifestations and may include:

• Blurred vision;
• Eye pain;
• Partial vision loss;
• Double vision (diplopia);
• Difficulty distinguishing colors.

Sensory symptoms: often among the first signs of the disease and include:

• Tingling;
• Numbness;
• Burning sensation;
• Electric shock sensation when bending the neck (Lhermitte’s sign);
• Changes in temperature and touch perception.

Motor symptoms: when lesions affect areas responsible for movement control, the following may occur: 

• Muscle weakness;
• Stiffness or spasticity;
• Difficulty walking;
• Impaired motor coordination;
• Tremors.

In addition to these symptoms, some individuals may experience urinary and bowel disturbances, cognitive difficulties, emotional changes, and chronic fatigue, which is considered one of the most disabling symptoms of the disease. 

What are the types of multiple sclerosis?

Multiple sclerosis is classified into four main types based on the initial clinical course of the disease (pattern of relapses and progression over time) (1, 9, 10). 

This classification helps define prognosis and guide the selection of the most appropriate treatment for each patient. 

Clinically isolated syndrome (CIS)

This corresponds to the first neurological episode suggestive of central nervous system demyelination and may represent the initial manifestation of multiple sclerosis. This event may present optic neuritis, myelitis, or brainstem involvement, causing symptoms such as visual disturbances, weakness, numbness, or balance problems. 

Not all individuals with CIS will go on to develop multiple sclerosis. However, the presence of characteristic lesions on MRI is associated with a higher risk of new demyelinating events and progression to clinically definite disease (1). 

For this reason, neurological follow-up and additional testing are essential to assess the risk of progression and guide appropriate patient management. 

Relapsing-remitting multiple sclerosis (RRMS)

This is the most common form of disease, accounting for approximately 85% to 90% of cases at diagnosis. It is characterized by the occurrence of neurological relapses, defined as episodes of neurological dysfunction lasting more than 24 hours in the absence of fever or infection, followed by periods of remission (9). 

During remission, symptoms may completely resolve or only partially improve, leaving residual neurological deficits. Between relapses, there is typically no continuous progression of disability, although the accumulation of lesions over time may contribute to permanent impairments (9). 

RRMS usually begins in young adults, with an average onset around 30 years of age, and is approximately three times more common in women than in men (9). 

Primary progressive multiple sclerosis (PPMS)

This form accounts for approximately 10% to 15% of multiple sclerosis cases. Unlike the relapsing-remitting form, it is characterized by a gradual and continuous worsening of neurological disability from disease onset, without clearly defined relapses in most patients (1, 9). 

Clinical manifestations typically develop insidiously and progress slowly over time. The most common symptoms include muscle weakness, difficulty walking, balance impairment, and gait disturbances, reflecting progressive damage to motor pathways.

PPMS usually presents around the age of 40. In addition, unlike other forms of the disease, there is no significant sex predominance, affecting men and women similarly (9). 

Secondary progressive multiple sclerosis (SPMS)

This represents a later stage of relapsing-remitting multiple sclerosis. In this phase, patients experience a gradual and continuous worsening of neurological disability over time, reflecting a greater contribution of neurodegenerative mechanisms to disease progression. 

Although some patients may continue to experience relapses during this phase, the defining feature of SPMS is the progression of disability independent of acute inflammatory activity. As a result, motor impairment, walking difficulties, balance problems, and functional limitations may become more pronounced over the years. It is estimated that between 15% and 30% of individuals initially diagnosed with RRMS will develop the secondary progressive form in the long term (1, 5). 

Which tests help diagnose multiple sclerosis? 

Currently, there is no single test capable of definitively diagnosing multiple sclerosis on its own. Diagnosis is based on the McDonald Criteria (2017, updated in 2024), which require evidence of inflammatory lesions disseminated across different areas of the central nervous system and occurring at different points in time, along with the exclusion of alternative diagnoses (11, 12). 

The most commonly requested tests include: 

Magnetic resonance imaging (MRI):

Considered the key test for investigating multiple sclerosis. It allows the identification of characteristic lesions in the brain, spinal cord, and optic nerves. In addition to supporting diagnosis, MRI plays a crucial role in monitoring disease activity and response to treatment (11). 

Cerebrospinal fluid (CSF) analysis:

CSF analysis can provide important information when the diagnosis is not fully established. One of the most characteristic findings is the presence of oligoclonal bands of immunoglobulin G (IgG), observed in approximately 85% to 95% of patients with multiple sclerosis (13). 

Although this finding is not exclusive to the disease, its presence can increase diagnostic confidence when interpreted alongside other clinical data (13, 14). 

The assessment of free light chains can serve as a marker of intrathecal inflammation and is included in the McDonald Criteria as a complementary tool to support the diagnosis of multiple sclerosis (11). 

Evoked potentials:

Evoked potentials are neurophysiological tests that evaluate the speed of nerve impulse conduction. They can detect abnormalities in seemingly asymptomatic neural pathways and help demonstrate lesions in different regions of the central nervous system (11). 

Tests to exclude differential diagnoses:

Since there is no single definitive test for multiple sclerosis, diagnostic evaluation also aims to exclude other conditions that may cause similar symptoms. These may include tests for neuromyelitis optica (anti-aquaporin-4 and anti-MOG antibodies), systemic autoimmune diseases, infections such as syphilis and HIV, vitamin B12 and folate levels, and, in selected cases, genetic testing—such as when Fabry disease is suspected (12). 

Neurofilaments and their relationship with multiple sclerosis

Neurofilaments are structural proteins found in neurons, especially in axons, and play a key role in maintaining cellular integrity. When neuroaxonal damage occurs, as seen in multiple sclerosis, these proteins are released into the cerebrospinal fluid and the bloodstream. 

Among them, neurofilament light chain (NfL) has emerged as an important biomarker of neuronal damage and can be measured in both cerebrospinal fluid and blood (plasma or serum) (15, 16). 

Studies show that elevated NfL levels are associated with inflammatory disease activity, including clinical relapses and the appearance of new lesions on MRI. In addition, increased concentrations may be detected even in the absence of symptoms, reflecting subclinical inflammatory activity and ongoing neuroaxonal damage (16). 

Although NfL is not used alone to confirm the diagnosis of multiple sclerosis, it is increasingly recognized as a complementary tool for prognostic assessment and disease monitoring. 

Higher levels are associated with an increased risk of future disease activity, disability progression, and brain atrophy, while a reduction in levels after treatment initiation may indicate an adequate therapeutic response. Therefore, NfL has the potential to support more individualized clinical follow-up and treatment decision-making in patients with multiple sclerosis (17, 18). 

On the SYNLAB blog, we discuss the growing importance of neurofilaments as biomarkers for neurological diseases. Learn more about how they contribute to diagnosis and clinical monitoring here. 

Treatments for multiple sclerosis

Although there is currently no cure for multiple sclerosis, therapeutic advances over recent decades have significantly transformed disease management. Today, treatment aims to reduce the frequency of relapses, control inflammatory activity, slow disability progression, and preserve patients’ quality of life (1, 12). 

In general, multiple sclerosis treatment is based on three main pillars: disease-modifying therapies, management of acute relapses, and rehabilitation with multidisciplinary care. 

Disease-modifying therapies: These therapies involve medications that act on the immune system to reduce inflammatory activity in multiple sclerosis. Their goal is to decrease the occurrence of relapses, reduce the development of new lesions in the central nervous system, and slow the progression of disability. Currently, several therapeutic classes are available, allowing treatment to be tailored to the characteristics and disease activity of each patient (19, 20). 

Management of relapses: During relapses—when new symptoms appear or existing symptoms worsen—anti-inflammatory treatments, particularly corticosteroids, may be used to accelerate clinical recovery. In specific situations, other approaches may be considered when the response to initial treatment is insufficient (1, 12). 

Rehabilitation and multidisciplinary care: Rehabilitation is a fundamental part of multiple sclerosis treatment. Depending on each patient’s needs, care may involve professionals such as physiotherapists, occupational therapists, speech therapists, psychologists, nutritionists, and neurologists. Evidence shows that rehabilitation programs and supervised physical activity can improve mobility, functional independence, fatigue, and quality of life (21). 

In addition to medical treatment, healthy lifestyle habits—such as regular physical activity and continuous follow-up with a multidisciplinary team—also play an important role in disease control and maintaining well-being over time (20). 

Which tests does SYNLAB offer for the investigation and monitoring of multiple sclerosis?

SYNLAB offers laboratory biomarkers that can support both the diagnostic investigation and ongoing monitoring of multiple sclerosis. 

The main available tests include: 

• CSF IgG oligoclonal bands: a marker of intrathecal immunoglobulin synthesis, present in approximately 95% of patients with multiple sclerosis;
• Free kappa light chains: a biomarker of intrathecal inflammatory activity, used as a complementary test in disease investigation;
• Neurofilaments (NfL) in CSF and plasma: a marker of axonal damage, useful for assessing disease activity and monitoring treatment response;
• GFAP (Glial Fibrillary Acidic Protein): a biomarker of astroglial damage, with potential application in evaluating progression and monitoring multiple sclerosis.

Get to Know SYNLAB Group, a Reference in Medical Diagnostic Services!

Performing precise and updated tests is essential for more accurate diagnoses and better treatment guidance. SYNLAB is here to help you. 

We provide diagnostic solutions with strict quality control to the companies, patients, and physicians we serve. We have been in Brazil for over 10 years, operate in 36 countries across three continents, and are leaders in service provision in Europe. 

Contact the SYNLAB team and explore our portfolio. 

Frequently Asked Questions (FAQ)

What are the first signs of multiple sclerosis?

The first signs of multiple sclerosis can vary from person to person but often include visual disturbances such as blurred vision or pain when moving the eyes, as well as tingling, numbness, muscle weakness, difficulty walking, loss of balance, and severe fatigue. As these symptoms may occur in other conditions, medical evaluation is essential to determine the cause. 

How do I know if I have multiple sclerosis?

Suspected multiple sclerosis should be evaluated by a neurologist, especially when neurological symptoms persist for more than 24 hours or occur in recurrent episodes. Diagnosis is based on a combination of clinical history, neurological examination, MRI findings, and, in some cases, laboratory tests and cerebrospinal fluid analysis. 

Can blood tests detect multiple sclerosis?

There is no blood test that can independently confirm a diagnosis of multiple sclerosis. However, laboratory tests can help exclude other conditions with similar symptoms and assist in monitoring treatment safety and response. 

Is there a cure for multiple sclerosis?

Currently, there is no definitive cure for multiple sclerosis. However, available treatments can reduce relapse frequency, control disease activity, slow disability progression, and improve patients’ quality of life. 

Is multiple sclerosis hereditary?

Multiple sclerosis is not considered a classical hereditary disease. Although genetic factors increase susceptibility, most patients do not have a family history of the condition. It is believed to result from the interaction between genetic, environmental, and immunological factors. 

When should I see a doctor?

It is recommended to seek medical evaluation if you experience symptoms such as sudden vision loss, double vision, persistent tingling, numbness, muscle weakness, balance problems, difficulty walking, or unexplained urinary changes. Early investigation increases the chances of timely diagnosis and appropriate treatment. 

References 

1) Thompson AJ, Baranzini SE, Geurts J, Hemmer B, Ciccarelli O. Multiple sclerosis. Lancet. 2018 Apr 21;391(10130):1622-1636. doi: 10.1016/S0140-6736(18)30481-1.

2) Rida Zainab S, Zeb Khan J, Khalid Tipu M, Jahan F, Irshad N. A review on multiple sclerosis: Unravelling the complexities of pathogenesis, progression, mechanisms and therapeutic innovations. Neuroscience. 2025 Feb 16;567:133-149.

3) Walton C, King R, Rechtman L, et al. Rising prevalence of multiple sclerosis worldwide: Insights from the Atlas of MS. Multiple Sclerosis Journal. 2020;26(14):1816-1821.

4) Dendrou CA, Fugger L, Friese MA. Immunopathology of multiple sclerosis. Nat Rev Immunol. 2015 Sep 15;15(9):545-58.

5) Filippi M, Bar-Or A, Piehl F, Preziosa P, Solari A, Vukusic S, Rocca MA. Multiple sclerosis. Nat Rev Dis Primers. 2018 Nov 22;4(1):49. doi: 10.1038/s41572-018-0050-3. PMID: 30410033.

6) Reich DS, Lucchinetti CF, Calabresi PA. Multiple Sclerosis. N Engl J Med. 2018 Jan 11;378(2):169-180.

7) Sarkar, Sujan Kumar, Willson, Annie M. L., Jordan, Margaret A., The Plasticity of Immune Cell Response Complicates Dissecting the Underlying Pathology of Multiple Sclerosis, Journal of Immunology Research. 2024, 5383099. https://doi.org/10.1155/2024/5383099

8) Bjornevik K, Cortese M, Healy BC, Kuhle J, Mina MJ, Leng Y, Elledge SJ, Niebuhr DW, Scher AI, Munger KL, Ascherio A. Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis. Science. 2022 Jan 21;375(6578):296-301.

9) Brownlee WJ, Hardy TA, Fazekas F, Miller DH. Diagnosis of multiple sclerosis: progress and challenges. Lancet. 2017 Apr 1;389(10076):1336-1346.

10) Katz Sand I. Classification, diagnosis, and differential diagnosis of multiple sclerosis. Curr Opin Neurol. 2015 Jun;28(3):193-205.

11) Montalban X, Lebrun-Frénay C, Oh J, Arrambide G, Moccia M, Pia Amato M, Amezcua L, et al. Diagnosis of multiple sclerosis: 2024 revisions of the McDonald criteria. Lancet Neurol. 2025 Nov;24(11):e13.

12) McGinley MP, Goldschmidt CH, Rae-Grant AD. Diagnosis and Treatment of Multiple Sclerosis: A Review. JAMA. 2021;325(8):765–779.

13) Thompson AJ, Banwell BL, Barkhof F, Carroll WM, Coetzee T, Comi G, Correale J, et al. Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria. Lancet Neurol. 2018 Feb;17(2):162-173.

14) Dobson R, Giovannoni G. Multiple sclerosis – a review. Eur J Neurol. 2019 Jan;26(1):27-40. doi: 10.1111/ene.13819. Epub 2018 Nov 18. PMID: 30300457.

15) Ferreira-Atuesta C, Reyes S, Giovanonni G, Gnanapavan S. The Evolution of Neurofilament Light Chain in Multiple Sclerosis. Front Neurosci. 2021 Apr 6;15:642384.

16) Chitnis T, Magliozzi R, Abdelhak A, Kuhle J, Leppert D, Bielekova B. Blood and CSF biomarkers for multiple sclerosis: emerging clinical applications. Lancet Neurol. 2025 Dec;24(12):1066-1078.

17) Bittner S, Oh J, Havrdová EK, Tintoré M, Zipp F. The potential of serum neurofilament as biomarker for multiple sclerosis. Brain. 2021 Nov 29;144(10):2954-2963.

18) Leppert D, Kropshofer H, Häring DA, Dahlke F, Patil A, Meinert R, Tomic D, Kappos L, Kuhle J. Blood Neurofilament Light in Progressive Multiple Sclerosis: Post Hoc Analysis of 2 Randomized Controlled Trials. Neurology. 2022 May 24;98(21):e2120-e2131.

19) Freeman L, Longbrake EE, Coyle PK, Hendin B, Vollmer T. High-Efficacy Therapies for Treatment-Naïve Individuals with Relapsing-Remitting Multiple Sclerosis. CNS Drugs. 2022 Dec;36(12):1285-1299.

20) Saguil A, Farnell Iv EA, Jordan TS. Multiple Sclerosis: A Primary Care Perspective. Am Fam Physician. 2022 Aug;106(2):173-183. PMID: 35977131.

21) Amatya B, Khan F, Galea M. Rehabilitation for people with multiple sclerosis: an overview of Cochrane Reviews. Cochrane Database of Systematic Reviews 2019, Issue 1. Art. No.: CD012732. DOI: 10.1002/14651858.CD012732.pub2.