A demyelinating disease affects the nervous system and the neuronal myelin sheath, thus damaging the conduction of signals between nerves. The reduced conductibility leads to a loss of cognition, sensation, movement and others. Multiple sclerosis (MS) or disseminated sclerosis is an inflammatory disease that affects the myelin sheath around the axons located in the spinal cord and brain, leading to a destruction of the immune system.
The occurrence of MS is between 2 and 150 per 100,000 people, based on the region. Young adults in their 30s and women are more likely to develop the ilness. MS is three time more common in women than in men in the US, with numbers increasing. Men and women over 50 are equally affected. A patient suffering from this demyelinating disease can present almost any neurological symptom, with a prevalence of visual, sensory and motor impairments.
Multiple sclerosis can take many forms and develop new symptoms that occur in subtle attacks, or progress over time. No symptoms are experienced between attacks, although they can leave permanent neurological damage. Depression, an unstable mood and cognitive difficulties are often seen in MS patients. Higher than usual temperatures can cause Uhthoff’s phenomenon, a worsening of the symptoms. Lhermitte’s sign is an electric sensation that runs down the back when the patient bends the neck. Other symptoms include very pronounced reflexes, muscle weakness, ataxia, fatigue, bladder and bowel difficulties, problems with speech and muscle spasms.
The causes of MS are unknown, although it is most likely triggered by a combination of environmental and genetic factors. Many theories try to explain this demyelinating disease, but so far none was proven. Despite the fact that it is not considered a hereditary disease, some genetic variations can increase the predisposition. Family history, smoking and a low vitamin D production increase the risks. Some believe that microbes or viruses such as the Epstein-Barr virus or other human herpes viruses can trigger MS.
Because signs and symptoms are very similar to those of other conditions, multiple sclerosis is difficult to diagnose, especially in the early stages. The McDonald criteria for MS uses magnetic resonance imaging (MRI) techniques to facilitate the diagnosis. Occasionally a biopsy is required. Neuroimaging is the most commonly used tool, along with evoked potentials, analysis of cerebrospinal fluid, magnetic resonance imaging and contrast substance administered intravenously. There is no known cure for MS, although some therapies can prevent disability and return function after an attack.