Iatrogenic short segmental stricture urethra

Clinical History

A 35-year-old male patient presented with acute retention of urine. The patient had a significant history of similar episodes of retention of urine in the past. Many of those episodes were managed by catheterization. There were 3-4 episodes of haematuria in the past year. There was no history of trauma, diabetes or hypertension.

Imaging Findings

Radiography of the pelvis was done to rule out any old healed fractures of the pelvis which may point towards the traumatic aetiology of urethral stricture. There was no evidence of any old healed fracture on control radiograph. On ultrasound there was evidence of minimal hydronephrosis of both kidneys. There was significant post-void residual urine. There was no evidence of benign prostatic enlargement or urolithiasis. An ascending urethrogram was done, which showed good opacification and good distensibility of anterior urethra. Contrast failed to ascend to membranous urethra but showed blind rounding. Micturating urethrogram showed minimal reflux changes on the left side. Posterior urethra was found to be dilated with irregular blind end. Sandwich film obtained demonstrated stricture segment involving bulbar and membranous part of urethra and the length of the involved segment could be determined.

Discussion

A urethral stricture is a narrowing of a section of the urethra. This narrowing of the urethra may be secondary to infections, instrumentation, congenital, or secondary to malignant growth. The most common cause of urethral stricture is iatrogenic [1]. The common causes of iatrogenic urethral stricture include repeated and forceful catheterizations, brachytherapy and prostatic resection. The incidence of urethral stricture following transurethral prostatic resection is approximately 5% [2]. Other causes include trauma and post-radiotherapy strictures [3, 4].
The pathogenesis of urethral stricture is poorly understood. Irrespective of the aetiological insult, formation of microscopic submucosal scars followed by extensive squamous metaplasia seems to be the responsible mechanism [5]. Urethral strictures are most commonly found in the bulbar part (50%), penile part (30%) and navicular fossa (20%). The strictures of the posterior urethra are usually rare and their aetiology is usually traumatic or neoplastic [6].
The patient usually presents with difficulty in micturition, incomplete evacuation of bladder, urgency of urine, symptoms related to urinary tract infections. In late stages the patient may develop end stage renal disease [7].
There are various imaging modalities which are useful in determining the aetiology and the extent of urethral stricture. As far as posterior urethral injuries are concerned, X-ray pelvis may show pelvic fracture [8]. Ascending urethrogram is one of the gold standard tests to diagnose urethral stricture. In this technique pre-warmed contrast medium is injected distal to fossa navicularis using a balloon catheter under fluoroscopic control and steep oblique films are taken. [9] It demonstrates the anterior urethra very well in terms of distensibility and contour. But in some patients, like in this patient, there is a blind ending pouch. In this situation it is not possible to ascertain the total segment involved in stricture formation because in this situation the proximal end of the stricture cannot be demonstrated. It is of paramount surgical importance to demonstrate the proximal and distal part of the stricture. To solve this problem a combination of micturating cystourethrography and anterior urethrography is simultaneously done. This procedure is known as sandwich urethrogram. This, like in this patient, can demonstrate the true length of urethral stricture which will help the clinician to decide on surgical options (endoscopic repair, single stage buccal mucosa or multistage repair) [10].
In developing countries like India where many patients cannot afford MR urethrogram, sandwich urethrogram (a combination of ascending urethrogram and micturating cystourethrography) can be a viable alternative.

Differential Diagnosis List

Final Diagnosis

Iatrogenic traumatic short urethral stricture involving bulb and membranous urethra

URL:	https://www.eurorad.org/case/12112
DOI:	10.1594/EURORAD/CASE.12112
ISSN:	1563-4086