A Quick Overview of MS Terminology
What are the common types of MS?
On average, 80 percent of people with MS begin with the relapsing-remitting form of MS (RRMS). This type of MS has temporary symptom flare-ups (also known as "relapses" or "exacerbations"), followed by a complete or partial recovery ("remission"). If untreated, more than 90 percent of individuals with RRMS may eventually advance to secondary-progressive MS (SPMS), within 25 years. This phase is reached when the patient experiences a progressive worsening of symptoms.
While approximately 80 percent of individuals with MS are initially diagnosed with RRMS, the majority of the other 20 percent are diagnosed with primary-progressive MS (PPMS). This form of MS presents a gradual but steady accumulation of neurological problems from the onset, without the presence of relapses and remissions. Other types of MS exist, but these are less common.
Prior to a diagnosis of MS, individuals may be diagnosed with clinically isolated syndrome (CIS). This is a single attack (or the appearance of one or more symptoms characteristic of MS) with a very high risk of developing MS.
What causes the symptoms of MS?
Nerve fibers (or axons) have a protective, fatty-rich protein covering known as myelin, which insulates the nerve fibers. MS is thought to be an autoimmune disease, where the body's immune system malfunctions by sending disease-fighting cells into the central nervous system (CNS) to destroy the body's own myelin. The CNS consists of the brain, optic nerves and spinal cord.
White blood cells, including lymphocytes, are produced when the immune system perceives a foreign body and instructs the cells to eliminate it. With MS, as these damaging immune-system cells circulate in the blood, they are able to breakthrough the protective blood-brain barrier (BBB) and enter the CNS.
Once the damaging cells enter the CNS, inflammation occurs in the areas where myelin becomes damaged and scarred. Areas of activity are known as lesions (or plaques). Ultimately, axons may become damaged as well. The flow of nerve impulses is interrupted along damaged areas of the myelin and nerve, causing the symptoms of MS.
What are some of the common tools used to evaluate MS activity?
Lesions may be viewed by a magnetic resonance imaging (MRI) scan of the brain and/or spine. Inflammation with these lesions can be better evaluated with gadolinium-enhancement - a type of dye given to the patient via injection prior to the procedure. A lumbar puncture (also known as a spinal tap) is a procedure where a very thin needle is inserted at the base of the spine and a small amount of cerebrospinal fluid (CSF) is collected. The neurologist will particularly be looking for oligoclonal bands, which are abnormal immune proteins called immunoglobulins.
Evoked potential (EP) tests measure the speed of the brain's response to visual, auditory (sound), or sensory (feeling) stimuli, using electrodes taped to the patient's head. Delayed responses can indicate possible damage to the nerve pathways. The Kurtzke Expanded Disability Status Scale (EDSS) uses whole and half numbers from one to 10 to measure degree of disability, largely in terms of mobility.
For a full explanation of MS terms, please visit www.mymsaa.org/publications/summer-07/health.
|Last Updated on Monday, 25 March 2013 12:31|