A urethral stricture is a narrowing of the urethra caused by injury or disease such as urinary tract infections or other forms of urethritis.
During the early stages of the condition, the subject may experience pain during urination and the inability to fully empty the bladder. It is not uncommon for the bladder's capacity to significantly increase due to this inability to completely void.
Urethral strictures may cause problems with urination, including in certain cases the complete inability to urinate, which is a medical emergency.
Urethral strictures are generally caused by either injury-related trauma to the tract or by a viral or bacterial infection of the tract, often caused by certain STD's. The body's attempt to repair the damage caused by the injury or infection creates a buildup of scar tissue in the tract resulting in a significant narrowing or even closure of the passage. Instrumentation of the urethra, particularly before the advent of flexible uro-endoscopy, was (and remains) an important causative event.
Short strictures in the bulbar urethra, particularly between the proximal 1/3 and distal 2/3 of the bulb, may be congenital. They probably form as a membrane at the junction between the posterior and anterior urethral segments. It is not usually noticeable until later in life, as it fails to widen as the urethra does with growth, thus it only impedes urinary flow relative to the rest of the urethra after puberty. Moreover, the patient will often not "know any different", and so will not complain about poor flow.
The urethra runs between the legs very close to the skin, leaving it vulnerable to trauma. Simply falling off a bike and hitting between the legs may result in the formation of scar tissue within the urethra tract. This condition is often not found until the patient has problems urinating because these are painless growths of scar tissue.
Passage of kidney stones through the urethra can be painful and subsequently can lead to urethral strictures.