There are many causes of cystitis, including the following: the first is intrinsic to the bladder, such as bladder stones, bladder foreign bodies, and bladder tumors, and the most common cause is indwelling catheters, which disrupt the mucosal defenses of the bladder and lead to inflammation of the bladder. The second is a downstream infection, which is an infection of the bladder secondary to a kidney. The bladder can be caused by infection of neighboring organs, by lymphatic spread or by direct spread, divided into bacterial and non-bacterial, bacterial generally refers to some of our common infecting bacteria, the most common being Escherichia coli, followed by Staphylococcus. Non-bacterial is generally a specific one, such as Mycobacterium tuberculosis, and bladder tuberculosis can also cause the manifestation of inflammatory bladder disease. The third mainly refers to neurological damage, men with neurological lesions, which can also cause inflammation of the bladder secondary to the disease.