The problem of pyelocystitis in infancy and childhood has become more and more important as our knowledge of the frequency of the infection has increased, and the possible serious consequences that it may entail. A few facts regarding pyelocystitis have been pretty well established, namely, that the infection is very much more common in girls than in boys, that the infecting organism is most frequently the Bacillus coli, and that the symptomatology of the condition is so indefinite as to make a diagnosis practically entirely dependent on the examination of the urine.
Regarding the mode of infection there seems to be considerable difference of opinion. In practically all articles on the subject, three possible modes of infection are given, namely, (1) ascending infection in the lumen of the urethra; (2) infection by way of the anastomosing lymphatics of large intestines and urinary tract; (3) infection by way of blood stream.