« Pneumonia Basics | Main | Post Traumatic Stress Disorder »

Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating disease, a non-contagious chronic autoimmune disorder of the central nervous system which can present with a variety of neurological symptoms occurring in attacks or slowly progressing over time. It has no cure yet and the exact cause remains unknown. Due to its effects of the nervous system, it can lead to long-term impaired mobility and disability in the more severe cases.

Diagnosis and early symptoms of MS

A definite diagnosis of MS requires evidence for dissemination of lesions within the central nervous system both in space and in time. This means that not only must there exist evidence of at least two distinct lesions, verifiable by clinical symptoms or by Magnetic Resonance Imaging (MRI), there must also be evidence of an occurrence of new symptoms or lesions within a time interval of at least 30 days. A lumbar puncture, which is a procedure done to collect a sample of cerebrospinal fluid, is useful for providing evidence of chronic inflammation of the central nervous system, often indicated by oligoclonal banding. Nerve conduction studies of optic, sensory and motor nerves can provide further evidence for MS, as the process of demyelination results in reduced nerve conduction velocities. The diagnostic process is completed by several laboratory tests to exclude other diseases that can mimic MS, such as sarcoidosis, vasculitis, and Lyme disease.

Early symptoms of Multiple Sclerosis

Affected individuals may experience a wide variety of symptoms, such as vision loss, double vision, nystagmus, difficulty with speech, various kinds of tremor, clumsiness of the hands, unsteady gait, weakness, spasticity, numbness, and bladder, bowel, as well as sexual dysfunction. Various cognitive impairments are also common, such as difficulty performing multiple tasks at once, difficulty following detailed instructions, loss of short term memory, depression, and fatigue.

Disease course and clinical subtypes

In most cases MS starts with an acute flare-up of symptoms within hours to days, called a relapse, exacerbation, bout, episode, or attack. Inflammation of an optic nerve (optic neuritis), causing painfulness of eye movement and visual deterioration frequently is the first symptom. However, not all patients with optic neuritis develop MS. Sensory disturbances such as numbness or tingling sensations are other frequent initial symptoms. In principle, MS can start with any of the symptoms mentioned in the section above.

Especially in early phases of the disease, symptoms frequently decrease or resolve spontaneously within days to months. Therefore, this disease course is called relapsing remitting. New relapses can occur within weeks to many years and can include formerly experienced and/or new symptoms. However, MRI studies have shown that nerve damage can continue in relapsing remitting patients even if symptoms subside. It has long been known that "MS never sleeps". This highlights the importance of preventive treatment if and when it is available. In many cases, the disease course changes after several years and symptoms start to progress slowly with or without superimposed relapses. This course is called secondary chronic-progressive, or just secondary progressive. However, some patients stay in a relapsing remitting course for the rest of their lives. About 10% of all MS-affected individuals experience chronic progression without relapses from onset of symptoms. This course is called primary progressive and frequently comes along with weakness of the legs, gait and bladder disturbances. Degenerative processes and not inflammation are thought to play the most important role in this clinical disease course. Chronic progression from onset of symptoms with superimposed relapses is referred to as relapsing progressive.

Posted by Staff at May 13, 2005 6:49 AM

blog comments powered by Disqus

Comments Archive

Posted by: Luz María Arce Romero MD at July 27, 2006 5:38 AM