Brain & Nervous System
MULTIPLE SCLEROSIS: Multiple sclerosis (MS) is a chronic neurological disorder, an autoimmune disease. It can be defined as damage to the insulating covers of nerve cells in the brain and spinal cord (Myelin). Myelin is composed of protein and fatty acids that make up a protective coating for nerve fibers (axons). In addition to causing damage to the myelin sheath, MS also damages the nerve cell bodies, as well as the axons themselves. As the disease progresses, the outermost layer of the brain, called the cerebral cortex, shrinks. MS affects people differently. A small number of people with MS will have mild symptoms with little disability, whereas others will experience worsening symptoms that will lead to increased disability over time. Most people with MS have short periods of symptoms that resolve fully or partially after they appear. These periods are followed by long stretches without noticeable symptoms. Most people with MS have a normal life expectancy. This damage disrupts the ability of parts of the nervous system to communicate, resulting in a wide range of signs & symptoms, including physical, mental, and sometimes psychiatric problems. MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms). Between attacks, symptoms may go away completely; however, permanent neurological problems often occur, especially as the disease advances. MS affects the brain and spinal cord. Early MS symptoms include weakness, tingling, numbness, and blurred vision. Other signs are muscle stiffness, thinking problems, urinary problems, clumsiness or lack of coordination, loss of balance, and weakness in an arm or leg. Patients may have their first symptoms between the ages of 20 and 40 years. Usually, the symptoms get better, but then they come back. Some may come and go, while others linger. Further symptoms may differ from patient to patient. Patients may have just a single symptom for months and years before other symptoms take place. However, symptoms in other patients may become worse within weeks or months. MS can be of either of the four types:
- Clinically isolated syndrome (CIS)
- Relapsing-remitting MS (RRMS)
- Secondary progressive MS (SPMS)
- Primary progressive MS (PPMS)
The symptoms of MS depend on the severity of the attacks as well as the location and size of the plaques. Early MS symptoms often include – Vision problems, such as double vision or optic neuritis (inflammation of the optic nerve), which causes pain with eye movement and vision loss, Muscle weakness, often in the arms and legs, and muscle stiffness with painful muscle spasms, Tingling, numbness, or pain in the arms, legs, trunk, or face, Clumsiness, especially difficulty staying balanced when walking, Bladder control problems, Intermittent or constant dizziness. MS may be associated with other symptoms also, such as – Mental or physical fatigue, Mood changes such as depression or difficulty with emotional expression or control, Cognitive changes, including problems concentrating, multitasking, thinking, or learning, or difficulties with memory or judgment, Muscle weakness, stiffness, and spasms may be severe enough to affect walking or standing. In some cases, MS leads to partial or complete paralysis. Many people with MS find that their symptoms are worse when they have a fever or are exposed to heat or following common infections.
Diagnostic Tests : Sclerosis is a medical term for the distinctive areas of scar-like tissue (also called plaques or lesions) that result from the attack on myelin by the immune system. These areas are visible on an MRI. A special dye or contrast agent may be injected into a vein to enhance the brain images. In addition, following tests may also be done : –
Lumbar puncture – This is done to obtain a sample of cerebrospinal fluid and examine it for proteins and inflammatory cells associated with the disease. This test can also indicate for diseases that may look like MS.
- Evoked potential tests – This is another test in which electrodes are placed on the skin and painless electric signals are given to measure how quickly and accurately the nervous system responds to stimulation.
- Optic Coherence Tomography (OCT) may also be done to detect optic nerve lesions, ,
In most cases, doctors can diagnose MS by assessing symptoms and identifying characteristic MS signs on an MRI. The patches of scar-like tissue can be as small as the head of a pin or as large as a golf ball.
Research indicates that people who spend more time in the sun, and those with relatively higher levels of vitamin D, are less likely to develop MS than those who do not. Additionally, people with MS who spend significant time in the sun and/or have higher vitamin D levels have a less severe course of disease and fewer relapses. Bright sunlight helps human skin produce vitamin D. Researchers believe that vitamin D may help regulate the immune system in ways that reduce the risk of MS and autoimmune disorders in general. Studies have also found that people who smoke are more likely to develop MS and have a more aggressive disease course. They also tend to have more brain lesions and brain shrinkage than non-smokers.