Non-fatal subacute sclerosing leucoencephalitis.

Subacute sclerosing leucoencephalitis (S.S.L.E.), by which is meant not only the type of disease described by van Bogaert (1945) but also the inclusion body type earlier described by Dawson (1933), usually runs a progressive and ultimately fatal course of a few months. Osetowska's (1961) 50 cases from van Bogaert's laboratory included 48 with durations of 1-5-18 months and a mean duration of 6 5 months. However, there were also two patients in this series who survived for four and five years respectively, and a number of such cases are reported in the literature, sometimes with long periods of apparent arrest of the disease followed by further progression to a fatal end. The cases which we intend to describe are certainly very rare, in that after a long period of slowly progressive illness each patient recovered his former capacities to some degree; it is this fact of recovery which encourages us to think that we are not concerrred with remissions which will ultimately be followed by relapse and death. On the other hand, the necessary lack of full pathological confirmation of the diagnosis in these cases contrasts with most previous reports; indeed, such a paper as that of Osetowska, from the viewpoint of a pathologist, could not have been written had the outcome in each case not been fatal. Nevertheless, we think that the evidence in our cases is sufficiently strong to make the diagnosis almost certain. Brief reports on both patients have already been made (Cobb, 1966).