Multiple sclerosis (MS) is a neurodegenerative disorder caused by the immune system mistakenly attacking the myelin sheath, or the protective protein coat around nerve fibers. This results in inflammation, which further damages the myelin sheath as well as the nerve cells themselves, and the cells that produce myelin.
The immune system attack on myelin causes a disruption in electric signals traveling along the nerve fibers from the brain to the body and back. As a result, patients with MS experience many symptoms, including fatigue, numbness and tingling, muscle spasms, walking difficulties, pain, and bowel or bladder problems. Many patients also experience emotional changes, including depression, anxiety, and mood swings.
There is no single test to diagnose MS. Physicians diagnose the disease based on a series of physical and neurological examinations that can help eliminate other conditions. These tests include magnetic resonance imaging (MRI), blood and cerebrospinal fluid tests, and tests that measure electrical signals from the brain.
Types of MS
Patients with MS are broadly classified into four groups based on disease progression.
Clinically isolated syndrome
Relapsing-remitting multiple sclerosis
Relapsing-remitting multiple sclerosis (RRMS) is the most common type of MS. Patients experience attacks of increasing neurological symptoms, called exacerbations or relapses, followed by periods of partial or complete recovery. At various times, patients may have active, not active, or worsening neurological symptoms.
Secondary progressive multiple sclerosis
Secondary progressive multiple sclerosis (SPMS) is the secondary stage of MS that follows RRMS. Patients may have relapsing-remitting episodes initially but then experience a steady worsening of neurological symptoms.