Abstract

Studies of bladder histology were made in patients with recurrent urinary infection or symptoms of cystitis, with a view to establishing its relationship to symptoms, cystoscopic appearance, and bacilluria. Bladder biopsies were taken from the patients and compared with control material obtained at necropsy. Acute inflammatory changes were inconstant and sometimes sparse. Chronic inflammatory changes were often marked, and were ranked by severity into four grades. There was a statistically significant correlation between the more severe grades and the finding of bacilluria, which was not dependent on sex or age. The grades in patients with recurrent non-bacterial dysuria (`urethritis') lay between those of the controls and the infected patients, and were statistically different from both. There was no correlation between these grades and either symptoms or the finding of trigonal hyperaemia during cystoscopy. However, heavy lymphocytic infiltration, and particularly germinal follicle formation, frequently resulted in macroscopic tubercle-like nodules which were visible on cystoscopy. Such germinal follicles may contribute to local antibacterial defences by their production of immunoglobulins, and may explain the high antibacterial antibody titres sometimes found in the sera of subjects with infection confined to the lower urinary tract.