Multiple Sclerosis | What Happens When Your Immune System Attacks Your Brain?

Multiple Sclerosis (MS) is a chronic autoimmune disorder that affects the central nervous system (CNS), which includes the brain and spinal cord. In MS, the body's own immune system mistakenly attacks and damages the myelin sheath. Myelin is a fatty, protective substance that insulates nerve fibers, much like the coating on an electrical wire. This insulation is crucial for the rapid and efficient transmission of electrical signals, or nerve impulses, between the brain and the rest of the body. When myelin is damaged, a process called demyelination occurs. This damage disrupts or completely blocks the flow of nerve signals, leading to a wide range of unpredictable neurological symptoms. The inflammation associated with these immune attacks can also cause the formation of scar tissue, known as sclerosis or lesions, which further impairs nerve function. Understanding the role of myelin is fundamental to comprehending how MS disrupts bodily functions, from movement and sensation to cognitive processes.

MS manifests in several forms, but the two main courses are Relapsing-Remitting MS (RRMS) and Progressive MS. RRMS is the most common form at diagnosis, affecting approximately 85% of patients. It is characterized by distinct attacks, or relapses, of new or worsening neurological symptoms. These relapses are followed by periods of partial or complete recovery, known as remissions. During remission, symptoms may disappear entirely, and there is no apparent progression of the disease. In contrast, Progressive MS is characterized by a steady worsening of neurological function from the outset, without distinct relapses or remissions. This category is further divided into Primary Progressive MS (PPMS), where symptoms gradually worsen from onset, and Secondary Progressive MS (SPMS), which follows an initial relapsing-remitting course but then transitions into a progressive phase with or without occasional relapses.

The initial symptoms of Multiple Sclerosis are highly variable and depend on which part of the central nervous system is affected. Common early signs include vision problems, such as blurred or double vision, or a painful condition called optic neuritis. Many individuals experience numbness, tingling, or a pins-and-needles sensation, often in the limbs. Muscle weakness, stiffness, and spasms are also frequent. Another hallmark symptom is profound fatigue that is disproportionate to the activity performed. Dizziness and balance problems, leading to difficulty with coordination and walking, are also reported. Because these symptoms can be subtle and may come and go, they are sometimes initially dismissed, which can delay diagnosis.

Diagnosing MS is a multi-step process, as no single test can definitively confirm the condition. A neurologist will typically start with a detailed medical history and a thorough neurological examination. The cornerstone of diagnosis is Magnetic Resonance Imaging (MRI) of the brain and spinal cord. MRI scans can reveal the characteristic lesions or plaques caused by demyelination. To confirm the diagnosis, evidence of damage must be present in at least two different areas of the CNS at different points in time. Other diagnostic tools include Evoked Potential (EP) studies, which measure the speed of nerve signal transmission, and analysis of cerebrospinal fluid (CSF) obtained via a lumbar puncture, which can show abnormal levels of immune proteins.

While there is no cure for MS, a variety of treatments can help manage the condition effectively. The primary therapeutic strategy involves Disease-Modifying Therapies (DMTs). These medications work to reduce the frequency and severity of relapses, slow the accumulation of lesions in the brain and spinal cord, and delay the progression of disability. DMTs are available in various forms, including injections, oral medications, and intravenous infusions. In addition to DMTs, specific treatments are used to manage the symptoms of MS. For example, corticosteroids may be prescribed to reduce the inflammation during a severe relapse. Other medications can address specific symptoms like muscle stiffness, pain, fatigue, and bladder issues. Rehabilitation therapies, such as physical, occupational, and speech therapy, are also critical components of a comprehensive treatment plan, helping patients maintain function and independence.