This is the first study on the frequency, size, number, and location of plaques in clinically silent MS. Among the present 18 patients in whom MS was unexpectedly diagnosed at autopsy, it had been clinically silent in 13. An estimate of the prevalence of silent MS is about 25% of that diagnosed in vivo. In the silent group, the MS plaques were located mainly in the periventricular areas, and this may explain the silent nature of the disease.

Age at onset, debut symptoms, optic nerve signs, and severity of symptoms were evaluated from the medical records of 135 patients with MS. HLA-D/DR2 was significantly more frequent in rapidly progressive MS, and D/DR2 seemed to confer both susceptibility to the disease and to more rapid progression. However, D/DR3 seemed to protect against rapid progression.

The diagnosis of multiple sclerosis (MS) is clinical and verifiable at post mortem. Neuropathological examination of 518 consecutive patients with clinically definite MS revealed a correct diagnosis in 485 cases (94%). Clinical diagnosis had been established by a neurologist in all cases. Erroneous diagnosis included a variety of other neurological disorders. Also investigated was a randomly selected series of 33 patients with a clinical diagnosis of probable MS: post mortem confirmation of MS was obtained in circa 66%, for the remainder the error pattern was similar to the above. Clinical diagnosis of definite MS was correct in 94% cases. Laboratory tests and examinations have not radically improved diagnosis. Neuropathological examination may occasionally fail to demonstrate MS plaques if the optic nerves are not investigated.

No abstract

Periphlebitis retinae (PR) in multiple sclerosis (MS) is seen as transitory infiltrations around veins in the otherwise normal retina. Cellular infiltrations have been found around veins in the central nervous system (CNS), where it has been suggested that they are the first event in plaque formation. Technetium brain scans are usually normal in MS patients, but transitory abnormal scans of the cerebrum have been found in MS patients during acute attack or exacerbation. In order to test the hypothesis that active PR is a sign of simultaneous disease activity in the CNS, 29 technetium brain scans were carried out on 14 MS patients with active PR and on 15 MS patients without any signs of PR. Significantly more of the patients with active PR, compared with MS patients with previous PR, displayed abnormal brain scans. This indicates that a disruption of the blood brain barrier (BBB) and active PR occur simultaneously in MS.