The association of anti-aquaporin 4 (anti-AQP4) antibodies and myelin oligodendrocyte glycoprotein antibodies (anti-MOG) in Devic disease acute disseminated encephalomyelitis will be discussed further on.
The clinician is well advised to make the diagnosis of MS on the firmest grounds possible and to withhold judgment unless the combination of clinical and laboratory features allows this degree of certainty. In the past, the passage of time was necessary to clarify the situation but presently, it is considered preferable to use MRI and other tests to attempt to establish the diagnosis at the time of the first symptoms. Certainly, the disease is likely when one of the usual syndromes, such as optic neuritis, bilateral brainstem symptoms, or transverse myelitis, occurs in a younger person. However, the time-honored—and still valid— criteria for diagnosis proposed by McAlpine and colleagues (1972), requiring several lesions that were “separated in time and space,” have been broadened greatly by the ability to detect demyelinating lesions by nonclinical means. This approach, in essence, predicts the likelihood that a clinically isolated syndrome (“CIS”) will disseminate over time and space and conform to the diagnosis of MS.
Polman and colleagues in 2011 have provided one of several published diagnostic schemes based on previous consensus (2001, 2005, and 2010; also McDonald et al 2001) that incorporates MRI changes into the criteria and further revisions have increased sensitivity (Table 35-2). These criteria are provided for the reader because they are often cited but they may prove unwieldy for routine clinical work and will undoubtedly be frequently updated. Our colleague Kurtzke apocryphally is said to have quipped “MS is what the experienced neurologist says it is.” All such criteria are also relevant to predicting the course of illness, which is discussed in the following text.
The intermittency of the clinical manifestations—the disease advancing in a series of attacks, each permitting remission—is perhaps the most important clinical attribute of most cases of MS. Some patients will have a complete clinical remission after the initial attack, or, there may be a series of exacerbations, each with complete remission; rarely, such exacerbations may be severe enough to have caused quadriplegia and pseudobulbar palsy. The average relapse rate is 0.3 to 0.4 attacks per year according to the calculations of McAlpine and Compston, but the interval between the opening symptom and the first relapse is highly variable. It occurred within 1 year in 30 percent of McAlpine’s cases and within 2 years in another 20 percent. A further 20 percent relapsed in 5 to 9 years, and another 10 percent in 10 to 30 years. Not only the length of this interval is remarkable, but also the fact that the basic pathologic process can remain potentially active for such a long time.