When you open a textbook on neurology and look up MS, it usually says: “MS is a relapsing disease of the central nervous system.” – Nevertheless, quite a few patients in my clinic ask: “What exactly is a relapse?”If you refer back to the textbook, a relapse is a newly occurred neurological deficit or a significant worsening of an already known neurological deficit, persisting for at least 24 – 48h. Example: A patient notices a numbness in his right arm in the morning after getting up, which increases during the day and leads to a fine motor skills disorder that still persists unchanged the next day. If this patient does not simultaneously suffer from an infectious disease with fever (e.g., classic flu-like infection), then it is an MS relapse – a therapy with cortisone can be offered to shorten the duration of symptoms.
Another example: An MS patient who has previously suffered from inflammation of the optic nerve in the right eye and already has visual impairments in this eye, notices that he suddenly sees significantly worse with this eye. The next morning, this visual impairment is still present. This is also a classic relapse – in this case, one would also quickly offer a cortisone infusion to reverse the symptoms.
It is important to distinguish relapses from intermittent symptoms – in neurology we also speak of so-called paroxysmal symptoms. We understand these to be short-term neurological disorders – such as abnormal sensations in arms and legs, visual disturbances or sensitivity disorders – which last less than 24 – (48h), namely only a few hours and often depend on temperature fluctuations (both from outside and inside). Especially newly diagnosed patients sometimes find it difficult to correctly classify such paroxysmal symptoms. Therefore, it is always a good tip to wait and observe the situation for at least one day when symptoms occur (unless it is a very serious deficit – in that case, one should immediately seek medical help).
Furthermore, it should be ruled out that the observed relapsing deterioration occurs in connection with an infectious disease. It is known that through the general activation of the immune system and the increase in body temperature as part of an infection, symptoms of MS can worsen or, in the worst case, even trigger a relapse. In this case, the treatment of the infection is priority – an uncritical administration of cortisone can then even be counterproductive. In such a case, we do not speak of a “real MS relapse”, but of an infection exacerbation.
Another rule is important: You should only speak of a new relapse at least 30 days after a previous relapse. Before that, one must assume that the old symptoms may have flared up again.
These rules are important insofar as most therapeutic recommendations are based on the number of previous relapses. If you do not follow these rules, there is a risk of misjudging the situation and possibly inadequate therapy.