Around 9,000 people in Ireland have Multiple Sclerosis (MS), a progressive neurological condition of the central nervous system causing, among other symptoms, tremors, fatigue, visual problems and limb weakness. Those with relapsing forms of MS will experience both relapses (exacerbations) and remissions (or recovery/stability). During relapses, new symptoms may occur and last for more than 24 hours.

"The strict definition of a relapse is when new symptoms appear, caused by new or active inflammation of the nervous system.”

A change in previous or existing symptoms may not be a relapse and therefore a relapse isn't always easy to recognise. “For instance, if a person with MS contracts a urinary tract infection or even a cold, they may transiently experience a worsening of their neurological symptoms,” says Professor Christopher McGuigan, Consultant Neurologist at St. Vincent's University Hospital in Dublin. “But that is not a relapse. The strict definition of a relapse is when new symptoms appear, caused by new or active inflammation of the nervous system.”

 

Recovery prospects from relapses

 

The symptoms of a relapse vary depending on the part of the nervous system affected, if the optic nerve is involved, there may be a persistent blurring or loss of vision in one eye for a few days to a few weeks. If the spinal cord is involved, weakness or sensory change in the lower limbs may occur for a few weeks.

"By their very nature, relapses are unpredictable and can flare at any time."

The vast majority of people who experience a relapse will recover over a period of days to weeks; and those who have been recently diagnosed in particular may experience a complete reversal of symptoms. “However, some relapses may leave behind residual symptoms,” says Professor McGuigan. “So a person may not completely return to their pre-relapse baseline.”

 

Reporting your relapse immediately

 

If you have MS and experience a relapse, you should tell your GP, MS nurse specialist or neurologist promptly. Not all relapses require immediate treatment, for instance with corticosteroids, as they will recover with or without steroids but they indicate to your neurologist the need for a longer term change in treatment plan and the need for disease-modifying treatments. “A relapse is a red flag that the underlying inflammation in the nervous system is not fully under control,” says Professor McGuigan. “Numerous disease modifying drugs are now available and, since their introduction, we are seeing fewer clinical relapses.” Those who relapse while established on disease-modifying treatment may need to be given a more efficacious drug.

“A relapse is a red flag that the underlying inflammation in the nervous system is not fully under control.”

Inflammation can also appear and disappear in the nervous system without causing symptoms, which is known as silent activity and only detected with an MRI scan. Ideally, therefore, those with relapsing forms of MS should have an MRI scan once a year. “Longer term silent activity still needs to be controlled in order to treat MS adequately,” says Professor McGuigan “so it should prompt the same management changes as a clinical relapse.”