 |
|
||||||||||||||||||||||||||
Heat Temperature Sensitivity
Many people with MS experience a temporary worsening of their symptoms when the weather is very hot or humid or they run a fever, sunbathe, get overheated from exercise, or take very hot showers or baths.
For example, some people notice that their vision becomes blurred when they get overheated - a phenomenon known as Uhthoff's sign. These temporary changes can result from even a very slight elevation in core body temperature (one-quarter to one-half of a degree) because an elevated temperature further impairs the ability of a demyelinated nerve to conduct electrical impulses. Myelin is the protective sheath that surrounds and protects nerve fibers.
The destruction of myelin causes the formation of plaques - abnormal areas - on the nerves that slow nerve impulses and produce the symptoms of MS.
The "Hot Bath" Test Used for Years to Diagnose MS
For many years, the "Hot Bath" test was used to diagnose MS. A person suspected of having MS was immersed in a hot tub of water and the appearance of neurological symptoms or their worsening was taken as evidence that the person had MS.
Symptoms Are Generally Rapidly Reversed
It is important to remember that heat generally produces only temporary worsening of symptoms and does not cause more actual tissue damage (demyelination or damage to the nerves themselves). The symptoms are generally rapidly reversed when the source of increased temperature is removed.
Air Conditioning Can Ease Effects of Heat
People with MS who are planning to move to a very warm climate should try to visit first. Plans may have to be changed if the weather seriously worsens MS symptoms. The adverse effects of heat may be eased if the person with MS remains in air conditioned surroundings as much as possible during periods of extreme heat.
Cold Can Also Be a Problem
Some people with MS notice that symptoms, particularly spasticity, become worse in cold weather. It is generally recommended that people with MS who are sensitive to temperature try to avoid extremes of either hot or cold and that people who are considering a move to a better climate try to visit first to see if the climate change is, indeed, beneficial. There are different cooling strategies that can be used, such as air conditioning and cooling vests. The MS Society can be a source of further information regarding these.
Exacerbation
An exacerbation (also known as an attack, a relapse) is a sudden worsening of an MS symptom or symptoms, or the appearance of new symptoms, which lasts at least 24 hours and is separated from a previous exacerbation by at least one month. The most common disease course in MS, called relapsing-remitting MS, is characterised by clearly defined acute exacerbations, followed by complete or partial recovery with no progression of the disease between attacks.
True Exacerbations Generally Last Days to Weeks
A true exacerbation of MS is caused by an area of inflammation in the central nervous system. This is followed by demyelination-the destruction of myelin, which is the fatty sheath that surrounds and protects the nerve fibers. Demyelination results in the formation of an abnormal area called a plaque and causes the nerve impulses to be slowed, distorted, or halted, producing the symptoms of MS. One example of an exacerbation of MS would be the development of optic neuritis, an inflammation of the optic nerve that impairs vision.
An exacerbation may be mild or may significantly interfere with the individual's daily life. Exacerbations usually last from several days to several weeks, although they may extend into months. It is generally accepted that a short course of corticosteroids will cause an exacerbation to be shorter and/or less severe.
Pseudoexacerbations Temporarily Aggravate MS Problems
Sometimes an increase in symptoms has nothing to do with the underlying MS, but is caused by factors such as fever, infection, or hot weather that can temporarily aggravate MS problems. This is referred to as a pseudoexacerbation. Some patients report a worsening of their symptoms during or after periods of intense stress. Researchers are exploring the effects of stress on the immune system and its possible involvement in MS.
Remission
A remission does not mean that all the symptoms of MS disappear, but rather that a person with MS returns to the baseline that existed before the last exacerbation began.
Source - NMSS Information Resource Center and Library. Compendium of Multiple Sclerosis Information (CMSI). © 2003, National Multiple Sclerosis Society. Reproduced with permission.
