Urethral Stricture : Causes, Symptoms and Treatment

A stricture is pathological or abnormal narrowing of a lumen. Therefore urethral stricture is a pathological narrowing of the urethral lumen due to scar tissue. As a result of this narrowing, a functional or anatomical obstruction can arise causing serious consequences of the urinary tract.

It produces obstructive and irritative urinary symptoms and can ultimately impair renal function.

In this article, we are going to have a detailed look at urethral stricture starting from the causes up to its management.

Causes and classification of Urethral stricture

They can be congenital or acquired or they can result from trauma, infection from either internal or external infections.

The majority of the acquired ones are iatrogenic and result from urethral manipulations such as a traumatic indwelling catheter, transurethral interventions, correction of hypospadias, prostatectomy, brachytherapy.

Another important cause of urethral stricture is the traumatic urethral rupture associated with pelvic fracture. Bacterial urethritis can also lead to a stricture in about 20% of cases; classically, these are cases of untreated gonorrhea.

Inflammatory disease associated with (distal) urethral stricture is balanitis xerotica obliterans, a chronic inflammatory disease whose exact etiology is unknown.

Some percentage of urethral strictures are idiopathic.

Bulbar strictures are most common (around 50%), followed by penile strictures (around 30%) and strictures of the navicular fossa.

The most common sites for its development are;

• Submental region and
• Bulbomembraneous region.

Morphologically, the stricture is an alteration of the urethra by scarring. In men, the corpus spongiosum in which the urethra is embedded is also involved in the scarring. This spongiofibrosis is a reaction to various extrinsic irritants and can lead to complete replacement of the spongy tissue by scar tissue.

Clinical Features

A narrowed or weak urine flow is the classical presentation of urethral strictures.

By the time the stream is noticeably thin, the luminal diameter has reduced considerably.

The main symptoms that patients with urethral stricture present with are those of obstructed and irritated urination, with increased urination time and a feeling of incomplete bladder emptying, increased micturition frequency and urgency.

Some patients do not present until they have acute urinary retention, since early on during stricture formation, the urinary bladder can compensate for the raised infravesical resistance by detrusor hypertrophy. This leads to a rise in intravesical pressure during urination, and may be noticed on ultrasonography as a thickening of the bladder wall.

Diagnosis

History taking like in any other disease condition is important in the diagnosis of urethral stricture.

uroflowmetry-The graph from a patient with a urethral stricture will show an extended urination time with a low-level plateau.

Strictures can be reliably diagnosed on the basis of uroflowmetry and cystourethrography.

Ascending urethrogram is the best diagnostic investigation in this case. The results of a urethrogram to be considered normal, the dye used should outline an anterior urethra of regular caliber and needs to be seen entering the bladder without any extravasation.

Treatment

In patients with urinary retention or large amounts of residual urine, blind transurethral bougienage of the urethra with an indwelling catheter must absolutely be avoided, as the tissue trauma would make the condition of the urethra worse. These patients should be given a suprapubic bladder fistula.

Treatment of urethral strictures is by dilatation using either rigid or flexible dilators.

Flexible dilators may be introduced to the urethra with a direct urethroscopic view or blindly with an experienced urologist.

Also, the patients may keep the urethra lumen patent by performing self-catheterization once or twice a week. When these catheters are being inserted, they should go completely up to the bladder. This is important because it will be an indicating factor that the whole of the urethra has been traversed.

If there if full-thickness bulbo-spongio-fibrosis, urethrotomy under supervision is unlikely to be successful.

For some short strictures, excision and re-anastomosis can be useful with substitution urethroplasty employed in other strictures.

The basic principle in the treatment of urethral stricture is that internal urethrotomy promises success only in short, first-time strictures.

In a recurrent stricture, treatment should be changed to open reconstruction, in order to avoid lengthening the defect by repeated urethrotomy.

Permanent elimination of a stricture often requires open reconstructive surgery.

What are the complications that may arise?

Restricturing. This is common after dilatation or urethrotomy.

Another important complication is bacteremia. This can result from the dilatation of the urethra. To prevent its occurrence its important that you administer prophylactic antibiotics before performing the procedure.

Antibiotics preferred are Gentamycin and amoxicillin.