This is a common question that particularly newly diagnosed patients bring to us at the center. The MS diagnosis is usually quite a shock. In most cases, it also comes as quite a surprise, as most affected individuals have been quite healthy until the point of diagnosis. This makes it all the more difficult to process a diagnosis of this magnitude. The variety of information available on the Internet about MS and possible differential diagnoses further contributes to uncertainty – and not infrequently, the competence of neurologists is questioned in chat forums or blogs of various providers and fear of misdiagnosis is stirred up. In the worst case, this uncertainty leads to avoidance behavior – one does not want to face reality and pursues the ostrich strategy. It is much better to seek a “second opinion” from another expert if there are fears and doubts about the diagnosis.
But what are actually the alternatives? Patients often worry that an infectious disease is being overlooked. Although most infectious diseases of the central nervous system follow a very different kinetics and are often much more serious than an MS relapse, there are of course also some chronic infections of the CNS that can resemble MS – here, for example, neuroborreliosis comes to mind (see also blog Neuroborreliosis). It can be said that in the cerebrospinal fluid examination (“nerve water examination”), which should always be carried out at the initial diagnosis of MS, borrelia is routinely tested for. In addition, borrelia leave a very specific signature in the cerebrospinal fluid, which an experienced neurologist usually does not overlook.
Other important differential diagnoses are other autoimmune diseases or diseases from the rheumatic spectrum, which can cause similar symptoms to MS when the central nervous system is involved. These include, for example, (neuro)sarcoidosis, systemic lupus erythematosus or various forms of systemic vasculitis (vessel inflammations) with CNS involvement. First and foremost, it must be noted that these diseases often progress much more unpleasantly and seriously than MS and their drug therapy, especially with CNS involvement, is not nearly as structured and clear as that of MS. On the other hand, the diseases mentioned above are systemic diseases, i.e., the patient often also suffers from involvement of other organs, such as the skin, the lungs or the kidneys. In addition, unlike MS, these diseases often stand out due to a significant reduction in general condition – so general feeling of illness, fever, night sweats. Despite these (often clear) clinical differences, these diseases are routinely screened for at the initial diagnosis of MS. We determine autoantibodies, examine the function of various organs in the laboratory and – if necessary – investigate any uncertainties.
Sometimes patients are assigned the differential diagnosis of a so-called “primary cerebral vasculitis of the CNS”, a very rare isolated vascular inflammation of the central nervous system. This disease does not show any systemic indications of the disease, like MS it only affects the central nervous system. However, it is usually a very aggressive disease that causes severe neuropsychological deficits and leads to rapid destruction of brain tissue without consistent therapeutic intervention – so a rather unlikely differential diagnosis when an otherwise healthy young patient sits across from you, who reports structured about his medical history.
An important differential diagnosis is undoubtedly Neuromyelitis optica (NMO). In the past, NMO was classified as a subtype of MS, but it is now considered a separate disease that also requires a different therapeutic strategy. Therefore, differentiation from MS is important for practical considerations. A characteristic of NMO in many cases is the presence of anti-aquaporin-4 antibodies, which are now routinely tested for (at least in MS centers). I will dedicate a separate post to NMO due to its special importance.
So it can be stated that although there are a considerable number of possible differential diagnoses, they can usually be distinguished quite well from MS with a structured clarification. If there are still doubts, it makes sense to obtain a “second opinion” from another MS center. This is always better than independently searching for alleged alternatives on the Internet and embarking on therapeutic missteps.
