Rupture of the spleen in naturally acquired malaria is considered by Osler1 to be a very rare complication. Manson-Bahr2 finds that in naturally acquired malaria the mortality from ruptured spleen is only about one in every hundred thousand infections. Davidson3 found 3 cases of ruptured spleen in 30,000 cases of malaria.
A review of the literature on malarial therapy for syphilis of the central nervous system, however, reveals a greater number of cases of ruptured spleen than would be expected, judging both from the statements referred to and from the observations of such authorities as Wagner-Jauregg (the father of induced malarial therapy), Weygandt, Driver and others. In a communication to Trömner4 dated July 9, 1925, Wagner-Jauregg stated that, in more than 1,200 cases treated by induced malaria since 1919, neither he nor his assistants found a single case of splenic rupture. Driver,5 in a review
POLAYES SH, LEDERER M. RUPTURE OF SPLEEN IN MALARIAL THERAPY IN SYPHILIS. JAMA. 1931;96(14):1127-1129. doi:10.1001/jama.1931.02720400025007