Why is it uncomfortable to urinate?

Why does a urethra get constricted?

I have difficulty emptying my bladder, what could this mean?

Causes of Urethral Strictures

Straddle Injury

A common urethral stricture cause is straddle trauma injury to the urethra. This may be a specific impact injury associated with bleeding and an inability to urinate. More often patients do not develop symptoms until months or years after an injury. These strictures are typically in the bulbar urethra (the portion of the urethra discussed in the previous section). In some cases, our patients are found to have bulbar strictures and do not recall a specific trauma. The bulbar urethra is relatively unprotected, and many boys and young men have some trauma to this area from a bicycle bar, a fence, being kicked, hit by a ball or any other impact to the scrotal area. In the absence of prior urologic procedures, we believe it is very unusual for a man to develop a bulbar stricture in the absence of trauma.

Pelvic Bone Fracture Posterior Urethral Disruptions

Common causes of pelvic fractures in men include automobile and motorcycle motor vehicle accidents and crush injuries, often work related. When the pelvis is fractured, in some cases there is an associated tear of the membranous portion of the posterior urethra. In most cases the ends separate, and the patient is completely unable to urinate.

Lichen Sclerosus (LS) = Balanitis Xerotica Oblitarans (BXO)

This is also known as Balanitis Xerotica Oblitarans or BXO. This is often a debilitating disease of unclear etiology. Men with LS have whitish discoloration of the penile skin and can develop strictures involving the meatus alone, or longer strictures.

Hypospadias Surgery

When a boy is born with an incomplete development of the urethra, called hypospadias, treatment with surgery to add tissue to the urethra and bring the opening to the tip of the penis can be complicated by urethral stricture development. This is more fully discussed in the Hypospadias section.

Urologic Procedures

When catheters or instruments are advanced through the urethra into the bladder to treat urologic or other diseases, the instrumentation can cause damage to the urethra and subsequent stricture formation. In particular, the fossa navicularis, the portion of the urethra close to the urethral opening at the tip of the penis, is the area most often affected. In addition, prostate surgery or radiation can be associated with very complex strictures involving the bladder neck and/or membranous urethra.

Other Causes

The above represents the most common causes of strictures. Other causes include foreign body insertion into the urethra and urologic surgeries such as penile implant surgery. We have noticed that certain large medical information websites that include a brief section on urethral strictures mention urinary tract infections an gonorrhea as causes of strictures and even suggest the cause is often infectious. While infections such as gonorrhea may be related to stricture formation, this is at most a very rare cause.

Urethral Stricture Symptoms

A common consequence of urethral stricture disease is a reduction in urine flow rate and a prolonged time needed to empty the bladder. This is similar to the way stepping on a garden hose or a kink in the hose is associated with a low flow of water out the end even when the affected area is a small segment of a long hose. Symptoms can develop suddenly or very gradually. In some cases, patients are so “used to” their slow flow rate, they do not appreciate that there was a problem, but when asked, recall that when standing next to others at a urinal, the sound is different, and others require less time to urinate.

If the only problem associated with stricture disease were a slow flow rate, it would be very reasonable for many patients to not pursue treatment and just “live with” the condition. Unfortunately, the obstruction to urine flow caused by urethral strictures can lead to many serious problems and consequences.

Bladder during urination
This is a normal bladder during urination after being filled with contrast material that appears white on an x-ray film. Notice that the contour of the interior of the bladder is smooth
Bladder after urination
This is a film obtained immediately after urination. Very little contrast remains. The amount of urine that remains in the bladder immediately after urination is called the post-void residual (PVR). It is normal for the PVR to be 0 or close to 0.

When there is urethral obstruction, the bladder has to squeeze harder to overcome the resistance. Eventually, the bladder thickens. This represents damage to the bladder. The interior of the bladder is no longer smooth. Visualization of the inside of the bladder reveals an abnormal strand like appearance, and imaging reveals significant irregularity of the bladder wall. This is called trabeculation.

bladder-trabeculation-08
Trabeculation on seen from within the bladder
trabeculation
Bladder imaging showing trabeculation

In some cases, as the bladder is further damaged, the high pressure required to overcome the resistance of urethral obstruction can actually cause the inner lining of the bladder to herniate through the muscle of the bladder leading to one our more outpouchings. These outpouchings, called bladder diverticula, are not surrounded by muscle and therefore may not empty during urination. This can lead to infections.

bladder diverticulum
Multiple diverticula
bladder diverticulum
Single very large diverticulum

In addition, the bladder can become enlarged. As this enlargement progresses, the bladder often becomes less able to empty during urination. Although, as previously mentioned, it is normal for the bladder to completely empty with urination, many of our patients are noted to have high residual urine volumes. It is not uncommon for patients to have residuals (PVRs) of 100-200cc. Some have such extensive bladder damage from prolonged obstruction, that their PVRs of over 700-800cc, twice the normal bladder capacity when a normal bladder is full.

This patient (film shown below) with stricture disease had a PVR of over 1000cc

PVR of over 1000cc
As the bladder becomes progressively damaged, additional symptoms can include frequent urination during the day and at night (called nocturia), sudden urges to urinate (urgency) and a sensation of incomplete emptying. Urine infections can occur. It should be remembered that although urine infections are not uncommon in women, they are rare in men and when a man develops even a single infection of the urine, evaluation is indicated to determine the reason as there is often an underlying cause that can be identified and addressed.

As was previously mentioned, the prostate gland and sperm from the testicles enter the urethra during ejaculation. This is generally a one-way flow towards the urethra. When there is distal blockage of the urethra, as is the case when there is a bulbar stricture for example, the pressure during urination within the bladder and urethra (i.e. the prostatic urethra) before the blockage is higher. This can lead to a flow of urine urination towards the prostate and/or epididymis/testicle, the wrong direction. When this happens, patients can develop infections of the prostate (called prostatitis), the epididymis (called epididymitis) or the testicle (called orchitis).

In some cases, urethral stricture disease is diagnosed when a man develops an infection and is evaluated, leading to the finding of urethral obstruction. Eventually, there can be a “backup” where some of the urine travels from the bladder back towards the kidneys.

Reflux Stricture Cause
This is called reflux (as shown).
Kidney infections and kidney and/or bladder stones can then occur. In severe cases, the kidneys can be reversibly or irreversibly damaged (renal failure).