Pathology and pathophysiology of painful bladder diseases

Painful bladder disease is an ill-defined disease presenting with chronic cystitis symptoms, despite sterile urine. This report includes only patients with painful bladder diseases of unknown etiology and pathogenesis. We have chosen to classify these patients pathoanatomically as follows: interstitial cystitis, detrusor myopathy, chronic unspecific cystitis and eosinophilic cystitis. The pathoanatomical appearance of the four groups of patients are described in details and certain clinical differences appear between the groups. The etiology and pathogenesis to the inflammatory reactions and muscle changes found in the detrusor biopsies are unknown, but many theories exist. It is suggested that something in the urine gains access to the bladder wall and initiates the pathoanatomical changes through a defective urothelium and glycosaminoglycans layer. In the interstitial cystitis patients, the inflammatory process and mast cell degranulation might be monitored by the urinary excretion of 1,4-methyl-imidazole-acetic acid and eosinophil cationic protein. It is concluded that no specific therapy for the disease exists, since etiology and pathogenesis are still unknown and therefore future research in this field is very important.