What is multiple sclerosis?
Multiple sclerosis (MS) is a chronic disease of the central nervous system, which includes the brain and spinal cord. It is an autoimmune condition in which the immune system mistakenly attacks the protective covering (myelin sheath) around nerve fibers. This damage disrupts the flow of information between the brain and the rest of the body.
Symptoms vary depending on the location and extent of nerve damage. They may include fatigue, numbness or tingling, muscle weakness or stiffness, balance and coordination problems, vision disturbances, pain, bladder and bowel issues, and cognitive difficulties. There is no cure, but treatments can manage symptoms, reduce relapse frequency, and slow progression. Most people with MS have a normal life expectancy.
Types of multiple sclerosis
- Relapsing-Remitting MS (RRMS): Relapses of new or worsening symptoms followed by periods of partial or complete recovery, with no progression during remissions.
- Secondary Progressive MS (SPMS): Begins as relapsing-remitting, then transitions to steady worsening of symptoms over time.
- Primary Progressive MS (PPMS): Steady progression of symptoms from onset, without early relapses or remissions.
- Progressive-Relapsing MS (PRMS): Steady worsening from the start, with acute relapses superimposed on that progression.
What causes multiple sclerosis?
The exact cause is unknown. It is thought to involve a combination of genetic susceptibility and environmental factors:
- Genetic factors: Family history and certain gene variants increase risk.
- Geography and vitamin D: MS is more common farther from the equator; low vitamin D levels may play a role.
- Infections: Viruses such as Epstein-Barr may trigger immune responses that damage myelin.
- Smoking: Increases risk and may accelerate progression.
- Other autoimmune conditions: Having another autoimmune disease can raise the likelihood of MS.
What are the symptoms of multiple sclerosis?
- Fatigue
- Numbness or tingling
- Muscle weakness and spasms
- Balance, coordination, and walking difficulties
- Vision problems, including blurred vision and optic neuritis
- Pain and spasticity
- Cognitive changes such as memory and concentration difficulties
- Bladder, bowel, and sexual dysfunction
- Dizziness and vertigo
- Emotional changes and depression
How is multiple sclerosis diagnosed?
Diagnosis combines clinical evaluation, imaging, and laboratory tests:
- Medical history and neurological exam
- MRI of brain and spinal cord to detect lesions
- Evoked potential tests to measure nerve response speed
- Cerebrospinal fluid analysis for immune markers such as oligoclonal bands
- Blood tests to exclude other conditions
- Criteria (McDonald Criteria) require evidence of lesions in multiple CNS areas and at different times, with other diagnoses ruled out
How is multiple sclerosis treated?
Treatment goals are to modify disease course, manage relapses, and address symptoms:
- Disease-Modifying Therapies (DMTs): Injectables, oral medications, and infusions to reduce relapse frequency and slow progression
- Corticosteroids: High-dose steroids for acute relapse management
- Plasma exchange: For severe relapses not responsive to steroids
- Symptom-specific treatments:
- Muscle relaxants for spasticity
- Pain relievers and neuropathic pain medications
- Fatigue-targeting drugs and lifestyle adjustments
- Bladder and bowel management strategies
- Rehabilitation: Physical, occupational, and speech therapy to maintain function
- Lifestyle and support: Regular exercise, balanced diet, smoking cessation, stress management, and counseling
Sources
- What is multiple sclerosis? National Multiple Sclerosis Society. Accessed Apr. 25, 2024.
- Multiple Sclerosis Overview. Multiple Sclerosis Association of America. Accessed Apr. 25, 2024.
- McDonald Criteria. MS Trust. Accessed Apr. 25, 2024.
- Multiple Sclerosis. National Institute of Neurological Disorders and Stroke. Accessed Apr. 25, 2024.
- Multiple Sclerosis. National Library of Medicine. Accessed Apr. 25, 2024.