The narrowing of the urethra – causes, symptoms and treatment
In most cases, the urethral stricture is noticeable by classical symptoms: Due to the constricted structure there is a weak urinary stream, moreover, also a painful urination and the tendency to recurrent infections of the urinary tract are characteristic. Early detection and the initiation of a consequent treatment are important to prevent that the disease leads to the complication of renal injury.
Urethral stricture – how does it develop?
The urethra is an important part of the urogenital tract. As the connection from the bladder to the outside, it ensures the excretion of urine. Whenever the narrow tube is reduced by a constriction in its inner diameter, the urine can not drain properly from the bladder and there is a risk of retention with all its consequences for the health. There are several possible causes for an urethral stricture, which occurs more frequently in men than among women because of their anatomical characteristics.
Often a scarring is the cause
A common reason for the urethral strictures are scarred structures that occur inside the urethra and restrict in this way the physiological drainage of urine from the bladder. Damages of the sensitive mucous membrane that lines the urethra from the inside, which lead to scarring, can be carried out from the outside or from the inside. 
External influences are usually injuries of a mechanical nature that may arise in case of accidents, especially in the area of sport. An unpleasant accident in this context is the slipping of cyclists from the pedals and the fall on the rod of the bicycle with the genital area. In cases of a fracture of the pelvis, for example as a result of a car accident, or open injuries in the region between perineum and penis or vagina the healing can also be associated with scarring, which then causes problems with urination due to urethral stricture.
Internal triggers contribute to the formation of scars inside the urethra area, too. A classic reason for urethral strictures in this context are medical examinations or interventions in the urogenital area. For example, the urethra is the path which the endoscope takes, a thin and flexible hose with a small camera at its tip, for urological mirroring such as the cystoscopy. Even in the case of cautious investigation so-called micro-injuries inside the urethra not always can be avoided. The often small damages of the mucous membrane of the urethra can lead to a scar and thus cause a stricture of the urethra.
Catheter as a classic trigger
After surgeries of any kind or in nursing, it may be temporarily or permanently necessary to use a urinary catheter for the patient, which controls the discharge of urine. How fine the small plastic tube may be, which is pushed through the urethra to the bladder, mucosal injuries are nevertheless possible, which may have small scars and a narrowing in the urethra area as a result. This is especially the case if a permanent catheter is inserted, as it may be necessary for example for treatments following difficult operations with a longer regeneration period. Here, the damage to the urethral mucosa can be done in two ways: On the one hand it is possible, that a permanent catheter leads to a circulatory disorder in this area via the pressure on the urethra, leading to an insufficient supply of blood and therefore degeneration of the affected tissue. On the other hand, catheters that contain latex may contain substances on their own, which may have a negative impact on the physiological structure of the fabric.
In order to avoid damages during the use of catheters which are in use for a longer period, resulting in constrictions of the urethra, so-called suprapubic catheters can be placed as an alternative to transurethral catheters, that are passed through the urethra. Here the urine is transported outwards via a thin hose through the abdominal wall.
Treating inflammations consistently
In addition to mechanical triggers such as catheters or injuries, the mucosa may be irritated by inflammations. These include the classical urinary tract infections, but also the sexually transmitted disease gonorrhea, colloquially known as clap, which is caused by bacteria, nowadays coming less frequently into appearance. 
During the healing of the inflammatory responses, scarring and a urethral stricture are possible as an additional complication, too. Germs in the area of the urogenital tract therefore should be carefully treated for two reasons – on the one hand, to prevent a rise of the germs in the kidney region, sometimes with serious complications, on the other hand, in order to prevent scarring of the urethral mucosa and thus prevent outflow obstructions.
Mucosa replaced by connective tissue
The process, by which the scarred narrowing of the urethra takes place, thereby happens regardless of the cause: The structural changes in the area of the tube lining mucosa cause the affected area to be completely or partially replaced by scars. The resulting tissue is significantly more rigid and stronger than the mucosa. 
The result is a shrinking and a narrowing of the urethra at the scarred places, while the degree of the urethral stricture depends on different factors such as the severity of the injury, the treatment made and not least on the regeneration abilities of the individual body.
In addition to scarred changes as the cause of urethral stricture in men, the benign prostatic hyperplasia is a common reason. In this disease there is an enlargement of the prostate through the new formation of tissue in this area. These changes are indeed benign, but because of taking space they result in the narrowing of the urethra, which manifests itself usually by an increasingly less pronounced urine. Of course, tumors can cause the stricture in the urethra area in the same way.
Congenital and acquired causes
In rare cases a narrowing of the urethra and thus an urinary obstruction is caused by a malformation of the urinary system or the sex organs, with which the child is already born. The hypospadias is an example. This is a developmental disorder that causes the mouth of the urethra to be located in the direction of the penis base. In addition there are often narrowings of the mouth, foreskin anomalies or undescended testicles.
However, most of the reasons for the clinical picture of urethral stricture are acquired strictures by scars, new formations of tissue or inflammatory diseases.
The symptoms of the narrowed urethra
It is a natural consequence of a stricture in the urethra that the stream of urine will become increasingly thinner over time, because the inner diameter of the urethra has narrowed by the constriction. Frequently, the weakened urinary flow is the first symptom, that is perceived by the persons concerned. In addition to the strength of the beam also its shape can change: A twisted manifestation of the beam or a split into several parts, reminding of the beam of a watering can, indicate a possible narrowing in the urethra. However, these symptoms are dependent on the location of the strictures and their individual severity. Also the so-called dribbling is a classic sign, which occurs only after the actual process of urination. This may indicate that a small bulge behind the narrowed point in the urethra has formed to restore the normal flow of urine.
Always take pain seriously
At the latest when pain occurs, the persons concerned are strongly advised to visit a doctor. 
If the patient feels the pain in the area of the perineum or penis, it is possible that this is caused by an urinary obstruction. Pain associated with urination is, furthermore, always a warning signal with regard to a bladder infection. This is a very typical result of a urethral stricture and is closely associated with the incomplete emptying of the bladder, arising therefrom, that occurs not infrequently: A bit of residual urine always remains in the bladder after urinating. The risk that in this amount of urine there are bacteria, which may multiply in their favorable environmental conditions, is immense. Indications of an already occurred urinary tract infection are painful urination, often with much less urine than usual, a reddish-colored urine and the frequent urge to urinate at night, that makes it often impossible for the patient to stay asleep and thus significantly limits the qualities of his life. When the infection has already reached the renal pelvis, it may be noted based on flank pain. Even the prostate and the epididymis may be affected by an inflammation and can indicate this by pronounced pain symptoms.
Complications must be strictly avoided
The urethral stricture causes not always significant discomfort, especially not during its initial stage. 
This is not necessarily just an advantage as consequential damage can be effectively prevented with a rapid and adequate course of therapy. Therefore it is all the more important to deal with emerging symptoms promptly, mainly because pain can be a signal for an incomplete emptying of the bladder and an infection in the area of the urogenital tract. To what extent complications occur depends on the degree of obstruction and the ability of the immune system to defend itself against bacterial infections.
Generally, however, a retention of urine causes negative influences on the rest of the urogenital tract in many cases. In men, inflammations of the prostate and the epididymis are painful complications. In both sexes, the residual urine, with its bacteria present in the liquid, can be damned up not only in the bladder, but also in higher-lying areas of the body such as the ureters that connect the bladder and kidneys and the renal region. Pain in the flanks and fever indicate an infection with renal involvement and are the reason for an immediate visit to the doctor, if the patient wants to prevent a permanent damage of the kidneys, possibly with the consequence of lifelong dialysis.
The complication of an unnoticed or untreated or improperly treated urinary tract infection is the urosepsis. Under certain circumstances life-threatening, the blood poisoning manifests itself by high fever and is an emergency, which can lead to multiple organ failure without timely treatment.
Retention of urine as an alarm signal
Also important as an emergency, the complete urinary retention is triggered by a very pronounced narrowing of the urethra. The patient recognizes it because of abdominal pain, caused not least by the massive overexpansion of the bladder that can not empty itself. Here not only the discharge of urine via a catheter through the abdominal wall and the elimination of the bottleneck are important for the treatment of the acute situation. It is also necessary to avoid the long-term effects of a chronic overstretched and flaccid bladder, as such a limited functional bladder constitutes a risk for infections due to the remaining residual urine again and again.
How is the urethral stricture diagnosed?
Care physicians and urologists often already suspect a narrowing due to the complaints of the patients such as the weak urinary stream and the trickling of residual urine. In addition, the diagnosis of urethral stricture can be backed up by specific studies:
The classical research method is the pressure flow measurement during which the urine is examined while urinating. The urine flow rate measurement can narrow down the causes of the weak urinary stream, since the beam always behaves the same in case of a urethral stricture. Using these diagnostics, the doctor can even get evidence of the possible existence of benign hyperplasia of the prostate.
During sonography, an experienced physician can depict changes in the regions of the bladder and the urethra on the ultrasound image. This applies not only to constrictions in the urethra, but also to the hypertrophied, thus thickened bladder. An advantage of the ultrasound examination is furthermore, that any remaining residual urine after urination becomes visible.
The ultrasonic diagnosis is often followed by a radiograph with a contrast medium which is introduced into the urethra, the so-called retrograde urethrography. Through the presentation of cavities in the radiograph, constrictions in their actual size become visible. The disadvantage of this examination is however, that changes – for example, expanded urethral areas near the stricture in relation to bladder pressure – can not be detected. Especially when planning an operation, a voiding cystourethrogram is made often. With this dynamic method of investigation recordings of urethra and bladder are made at the time of urination.
By mirroring the narrowing in the urethra can be viewed immediately. This is done using a thin and flexible endoscope. There is a small camera at the tip whose recordings are transferred directly to the monitor of the physician. The invasive endoscopy is usually performed in local anesthesia of the urethra and takes place only when there are still uncertainties due to the previous investigations.
In order to recognize and treat infections promptly – especially involving the kidneys – blood and urine tests are also included in the comprehensive diagnosis of urethral stricture.
Different treatment options
The treatment of the urethral stricture depends on a number of factors. First of all, the doctor will include the extent and the location of the constriction and the associated restrictions in his treatment recommendations. The cause of the narrowing also plays a major role. 
A tumor is of course to be removed as far as possible, while in case of a fresh injury with acute inflammation the healing process is awaited with conservative treatments before deciding for or against surgery. During this time the urethra is protected if necessary using the suprapubic bladder catheter. Depending on the cause of the disease (for example, injury or inflammation) appropriate medications like decongestants or antibiotics will be administered. The condition and the medical history of the patient also are important for therapeutic decisions. The age and significant comorbidities of the patient are taken into account, but also the fact whether it is a primary disease or a relapse.
Urethral stricture – invasive methods at a glance
Depending on the location of the stricture and the risk of a relapse, the optimal treatment for the individual patient can be selected from one of the following treatment options.
The dilation of the urethra (bougienage) is a relatively simple treatment method, proven in numerous applications and therefore established since a very long time. In some cases it can even be carried out by the patients themselves using disposable catheters that are coated with a special lubricant. With regular use, the method is referred to as long-term dilatation. But the bougienage entails considerable disadvantages, so therefore this measure is not the treatment of choice in most cases: On the one hand, the success of the distention is only temporary, on the other hand, the disease is often worsened in the long run by the repeated irritation of the mucous membrane, or by resulting micro-injuries.
With the help of a stent, however, it is possible to prevent permanently that a widened urethra narrows again. This is a small support, made of fine wire, which can keep the channel open. But even this method is not recommended because of the following reasons: The intrusion of scarred tissue in the wire mesh and chronic infections of the urinary tract due to the settlement of germs on the stent have been observed as disadvantages.
For a certain group of patients the endoscopically performed slitting of the urethra is suitable. Usually, the preconditions for this intervention are a first-time occurrence of urethral stricture and an affected area which should have an extension of no more than 1.5 centimeters. The advantage of this method of treatment, which requires a splint for about a day after the operation, lies in the relatively short time of the surgery and subsequent treatment. Each additional slitting leads to a further scarring of the urethra, and has a negative impact on the success of a urethroplasty performed later. Therefore repeated slits are to be judged critically, especially in younger patients.
The removal of portions of the urethra in conjunction with the insertion of a urethral plastic can only be done in an open operation. If the affected piece of urethra is at most two centimeters long and is located in the penile shaft, the surgeon can simply join the two ends, caused by the excision, and sew them together within the framework of a so-called anastomosis. The disadvantages of this method are however, that there may be a curvature of the penis and erection problems for a prolonged period.
A greater distance is usually bridged by the urethroplasty, for which usually a piece of oral mucosa of the patient is used. The advantage of this method lies in the comparatively low rate of recurrence. Disadvantages are the damages and risks that arise from the removal of oral mucosal flaps in the oral cavity.