Etiology and Epidemiology
Inflammation of the urinary bladder is the most significant clinical problem among all conditions affecting this organ. From an epidemiological perspective, this pathology has a distinct pattern: it is most frequently diagnosed in young women of reproductive age. However, in older age groups, gender differences even out, and inflammation becomes equally common in both sexes.
In the vast majority of cases, the etiology is linked to infectious agents. Intestinal flora play the leading role: E. coli, Proteus, Klebsiella, and Enterobacter. Viruses (particularly adenovirus), Chlamydia, and Mycoplasma initiate the inflammatory process significantly less often. Tuberculous cystitis warrants special attention, as in clinical practice it almost invariably leads to renal tuberculosis.
In addition to classic infections, there are iatrogenic (non-infectious) causes:
- Radiation cystitis: occurs as a direct consequence of irradiation of the bladder region.
- Hemorrhagic cystitis: develops during the administration of heavy cytotoxic drugs (cyclophosphamide, busulfan, methotrexate, ifosfamide, cisplatin).
Pathogenesis and Morphology of Acute Forms
The primary danger of infectious bladder involvement lies in the risk of ascending infection. Microorganisms are capable of retrogradely penetrating the pelvicalyceal system, causing a severe complication — bacterial pyelonephritis. Inflammatory diseases of the bladder are almost never fatal on their own (unlike bladder neoplasms, which are a significant cause of mortality).
Macroscopically and microscopically, the acute process in most cases represents nonspecific inflammation. Marked hyperemia of the mucosal membrane and an accumulation of inflammatory exudate are observed. Depending on the character of the exudate, the following morphological forms are distinguished:
- Hemorrhagic cystitis: characterized by a hemorrhagic component in the exudate. This form is typical for radiation therapy, chemotherapy, and adenovirus infection.
- Phlegmonous cystitis: manifests as an accumulation of purulent exudate.
- Ulcerative cystitis: develops under the influence of pyogenic flora and leads to ulceration of large areas or even the entire surface of the mucosa.
Chronic Progression and Specific Forms
If the infection persists for a long time, the process transitions to a chronic stage. The main morphological difference between chronic and acute cystitis lies in the composition of the inflammatory infiltrate. A prolonged course inevitably leads to structural remodeling: fibrous thickening of the lamina propria occurs. As a result, the bladder wall thickens and loses its elasticity.
Pathological anatomy distinguishes two specific histological forms of chronic inflammation:
- Follicular cystitis: a form in which lymphocytes accumulate in the mucosa and underlying layers, forming lymphoid follicles.
- Eosinophilic cystitis: characterized by eosinophil infiltration of the submucosal layer. This process is accompanied by the development of fibrosis and the appearance of giant cells in the tissues.