Which clinical manifestation would the nurse associate with a urethral stricture

» To understand the aspects of assessment and investigations used to diagnose urinary tract infections [UTIs] in men

While urinary tract infections [UTIs] are uncommon in healthy men aged under 50 years, their prevalence rises in men aged over 65 years. UTIs can be classified as uncomplicated or complicated. UTI in men is considered to be more complicated than in women, because it is often related to abnormalities of the urinary tract, such as prostatic enlargement or a urethral stricture. UTI is associated with a significant disease burden and cost to patients and healthcare organisations. It is one of the most common reasons for prescription of antibiotics in primary care; however, because antibiotic resistance is becoming increasingly widespread, it is essential that these drugs are used prudently. The main strategy for preventing UTIs in men is to avoid the use of indwelling catheters.

Nursing Standard. doi: 10.7748/ns.2018.e11039

Bardsley A [2018] Assessment, management and prevention of urinary tract infections in men. Nursing Standard. doi: 10.7748/ns.2018.e11039

This article has been subject to external double-blind peer review and checked for plagiarism using automated software

Urethral strictures cause obstructive urinary symptoms, which can be severe and affect the quality of life. They can be caused by many etiologies and can vary in severity. To avoid significant effects on life activities, urethral strictures should be diagnosed and investigated to offer the best treatment option. This activity describes the etiology, evaluation, and management of urethral strictures and highlights the role of the interprofessional team in providing care for patients with this condition.

Objectives:

• Describe the etiology and pathophysiology of urethral strictures.

• Review the appropriate history, physical, and evaluation of urethral strictures.

• Outline the management and current treatment options for urethral strictures.

• Summarize interprofessional team strategies for improving care for patients with urethral strictures.

Introduction

A urethral stricture is a narrowing of the urethra, causing obstructive symptoms. They usually result from injury to the urethral mucosa and tissues around it. It can develop anywhere along the length of the male urethra and can be due to many etiologies.[1] It is a common condition resulting in many office and hospital visits and admissions.[2] Urethral strictures can be classified into anterior and posterior, with the anterior ones comprising 92.2%. Most of them occur in the bulbar urethra alone [46.9%], followed by the penile urethra alone [30.5%], or a combined bulbar and penile stricture [9.9%], and finally pan-urethral strictures [4.9%].[3] Urethral strictures can occur in both sexes but are rare in females, which has led to lacking guidelines on how to diagnose and treat female strictures.[4] However, data on male urethral strictures is prevalent, and many treatment options are available. 

The male urethra extends from the external urethral meatus at the tip of the glans penis to the bladder neck proximally. It is contained within the corpus spongiosum, which lies in a groove below the two corpora cavernosa. The inside of the urethra is lined with stratified squamous epithelium. The urethra is divided into anterior [from the external urethral meatus to the distal membranous urethra] and posterior [from the distal membranous urethra to bladder neck] parts. However, the World Health Organization conference in 2002 recommended that this nomenclature should be discarded. According to the new nomenclature, the urethra is broken up into seven segments; the urethral meatus, followed by fossa navicularis, penile, bulbar, membranous, and prostatic urethra, and finally, the bladder neck.[5]

Etiology

The etiology of urethral strictures is divided into four major groups; idiopathic, iatrogenic, inflammatory, and traumatic, with the idiopathic and iatrogenic being the most common at 33% each. Following them are the traumatic causes comprising 19% and finally inflammatory, causing 15% of them.[6] 

With regards to idiopathic causes, there are clinical features that point towards the possibility of them being caused by unrecognized repetitive minor perineal traumas, eventually leading to the stricture.[7]

Iatrogenic causes are divided into five causes. Trans-urethral resections [TUR] comprise 41% of them.[6] During these procedures, the instruments are passed up and down the urethra repeatedly, leading to epithelial injury with stretching the urethra.[8] This urethral injury leads to stricture. Prolonged catheterization [36%] exerts pressure on the urethra leading to pressure necrosis in the epithelium.[6] Changes in the materials used for the make and design of catheters [using silicone instead of latex] has helped in reducing the incidence of strictures. Also, even with the use of intermittent catheterization techniques, strictures still do occur after prolonged periods of use.[5] Cystoscopy [12.7%] causes epithelial injury as well, leading to strictures.[6] Hypospadias repair causes 6.3% of the iatrogenic strictures.[6] Children who undergo repair have a 10% risk of developing urethral strictures later in life.[5] Prostatectomy [3.2%] is another cause of urethral strictures.[6] Urethral strictures complicate the cases of 8.4% of men who undergo treatment for prostate cancer, including prostatectomy, radiotherapy, and chemotherapy, causing stricture in the posterior or bulbar urethra.[9] The direct cause is not very clearly known, whether it is due to instrumental injuries during the procedure or postoperative bladder neck stenosis in the case of radical prostatectomy.[1] 

Inflammatory strictures can be the result of post-infectious inflammation leading to narrowing of the lumen and weakening of the epithelium, most commonly from recurrent gonococcal urethritis. These causes are becoming less common in the developed world due to public education, but some are still common in developing countries.[2] The connection of other infectious causes to urethral strictures is still unclear. There are suggestions that chlamydia, tuberculosis, and schistosomiasis can cause post-infectious inflammation and stricture.[5] Recurrent urinary tract infections [UTIs] can also cause urethral strictures, with the most isolated microorganism being Escherichia coli.[1] Lichen sclerosis [LS] is another cause of inflammatory urethral strictures. The cause and pathophysiology of the disease remain unclear; however, there is a possible genetic predisposition and an autoimmune factor. LS presents as pale, ivory lesions on the glans or vulva and surrounding the anus.[10] The lesions can extend into the urethral meatus and cause obstructive symptoms, leading to high pressure voiding against a narrowed urethra and causing further damage to the epithelium.[5] Inflammatory urethral strictures only affect the anterior part and do not extend to cause posterior urethral strictures.[2] Also, these strictures are significantly longer than the ones caused by other etiologies.[11] 

Post-traumatic anterior urethral strictures most commonly affect the bulbar urethra and are frequently due to straddle injuries compressing the bulbar urethra against the symphysis pubis. This pattern of injury is rarely associated with a pelvic fracture. Penile urethral strictures due to trauma are rare but can happen following a penile fracture.[2] Significant trauma leading to pelvic fracture causes a posterior urethral stricture almost exclusively in the bulbar or membranous urethra [almost 70 % of causes of membranous stenosis is traumatic pelvic future] as they are the site of urethral injury is these scenarios.[1] Although a small fraction of people who sustain a pelvic fracture develop structure [3%-25%], 84% of people with a traumatic posterior stricture have a pelvic fracture.[2] Moreover, post-traumatic urethral strictures tend to be short, with most of them less than four cm in length.[1]

Epidemiology

Urethral strictures are common, with its prevalence in the US being around 200/100,000 in younger men and more than 600/100,000 in men older than 65. The estimated annual incidence rate in The US is 0.9%.[2] Male urethral strictures account for 5,000 hospital admissions annually and 1.5 million visits to clinics.[3] In The UK, the prevalence is considerably less with an estimation of 40/100,000 in men up to 65 years of age and 100/100,000 afterward.[8] Worldwide, it is estimated that male urethral strictures have a prevalence of 229-627/100,000.[12]

Pathophysiology

The pathophysiology is an injury to the urethral epithelium attributed to any of the specific etiologies causing a leak of urine to the corpus spongiosum or by direct trauma to the corpus spongiosum. Either of which initiates inflammation and fibrous changes of the corpus spongiosum. This form of fibrous tissue causes contraction compressing the urethral lumen.[3] These also cause metaplasia of the urethral epithelium to stratified squamous epithelium, which is more affected by pressure changes and stretch causing tears in the mucosa, leading to a further leak of urine into the outer corpus spongiosum, which causes fibrous changes and stricture.[8] This process causes a vicious cycle of strictures and urethral injuries leading to further narrowing of the urethra, and so on.[2]

History and Physical

Most patients present with progressive obstructive voiding symptoms, mostly occurring as a weak stream. However, the severity of the symptoms can vary widely among patients. Especially in patients with slowly progressive or a discrete stricture. These can present with the absence of such symptoms. Usually, in this case, the patient will have detrusor hypertrophy compensating. Other obstructive symptoms can be hesitancy, intermittency, and dribbling.[13] The symptom most associated with strictures is the feeling of incomplete emptying. Patients can present with acute obstruction, more commonly hematuria, and even more commonly UTIs. But overall, 70% of all patients present with obstructive symptoms alone.[8]

Following the initial history taking, additional questioning should be focused on uncovering the underlying etiology. History of interventions, previous infections, and trauma should be sought as well. Finally, appropriate past medical history and comorbidities should be elucidated.[13]

Although that physical examination is usually unrewarding, performing a detailed one is still important. During the physical examination, the clinician should palpate the urethra feeling for any palpable fibrous tissue and look for any skin changes like pale patches pointing towards LS. On some occasions, these patches can be confined only to be surrounding the urethral meatus. Also, identify any scars indicating previous surgery. Examination of the prostate is very important, looking for benign prostatic hyperplasia [BPH], prostatic cancer, or prostatitis.[8][13]

Evaluation

Blood tests do not have a role in diagnosing urethral strictures. However, many lower urinary tract flow studies provide a detailed assessment of the urethra.

Uroflowmetry is the preferred initial investigation. It provides a good assessment of the urethral flow. Also, the interpretation of triphasic uroflowmetry provides data to distinguish patterns of healthy individuals, benign prostatic obstruction, and urethral strictures. A maximum flow [Qmax] of less than 15 mL per second raises the suspicion of lower urinary tract stricture. It is also of importance to study the curve shape to differentiate the cause. Urethral strictures typically produce a plateau at the level of Qmax. Ideally, uroflowmetry studies should be of more than 150mL in volume to yield reliable results.[13][14][15]

Urethroscopy or cystoscopy is a relatively easy and fast investigation to diagnose urethral stricture, and it can be done under local anesthesia [flexible cystoscopy]. It helps to determine the location of the stricture. However, it can be of limited use when it is unable to pass through the stricture to assess the length or the state of the urethra proximal to it. In this case, using a smaller caliber ureteroscope can sometimes help pass beyond the stricture and provide more information. Again, another limitation is its inability to provide information about the surrounding fibrosis. So, although it is of limited diagnostic value, it can provide a quick diagnosis in case of clinical doubt.[8][13][15]

Urethrography is the next investigation if the clinical picture and uroflowmetry suggest stricture to confirm the diagnosis. A retrograde urethrography [RUG] can visualize the entire urethra up to the bladder if the patient is relaxed. Frequently, especially when the stricture is significant and insufficient distention of the proximal urethra happens, RUG will not provide sufficient information about the proximal urethra and extent of the stricture. In such cases, a voiding cystourethrography [VCUG] will provide valuable additional information. This is by either asking the patient to void after the bladder is filled with contrast from the RUG or by introducing the contrast through a suprapubic catheter. The combination of RUG and VCUG yields a good image of the entire urethra. It provides information about the location, number, length, and severity of strictures. They are usually the most definitive diagnostic tools. However, these studies have limitations when interpreting the images. This relates to the position of the stricture and the state of the proximal urethra, as these techniques provide a 2D image of a 3D structure.[8][13] Some studies suggest that the use of computed tomography [CT] voiding urethrography or sonoelastography provides better images of the stricture and its characteristics.[16][17]

Ultrasonography [US] is mainly used to assess the bladder and upper urinary tract. It can show a thickened urinary bladder wall. Residual post-voiding urine can be seen on ultrasound as well, which may guide the clinician as to how significant the urethra is obstructed.[8][18] Also, ultrasonography may be useful when directly pointed at the area suspected to assess the presence of spongiofibrosis and possibly visualize the stricture zones when the urethra is filled with a physiologic solution through a Foley catheter.[13]   

Magnetic resonance imaging [MRI] scan use in diagnosing simple urethral strictures is debatable. However, it can provide excellent images when cancer is suspected to be the cause of the stricture, showing the location and extent of the tumor into surrounding tissues.[13]

Treatment / Management

When there are no complications, the treatment’s goal would be symptom relief only. The choice should be based on symptom severity and patient preference. If the symptoms are not troublesome, treatment should not be offered. However, if the patient presents with a complication like recurrent infections or acute retention, treatment would reduce the incidence of complications.[8] The normal urine flow rate in a healthy young male is greater than 15mL/s. Patients with stricture and flow rates between 10-15mL/s usually are asymptomatic. Provided that there is no increased bladder thickness or incomplete emptying, there is no need for any intervention. A flow rate of 5-10 mL/s is usually more associated with obstructive symptoms and complications. But again, this is not always the case. Treatment should only be offered for patients who have troublesome symptoms. If not, active monitoring should be undertaken. If the flow rate is below 5mL/s, there is an increased risk of acute retention, although this is not very common. This group of patients should be offered treatment, even if the symptoms are not significant.[18] In cases where patients present with acute complications, the acute complication should be dealt with first before offering treatment for the stricture. Patients presenting with acute urinary retention should be given a suprapubic bladder fistula. Any existing UTI is treated with antibiotics as well. Once this is dealt with, definitive treatment for the stricture should be undertaken.[15]

Generally speaking, urethral stricture treatment can be divided into transurethral [dilation, internal urethrotomy] and open surgical [stricture resection and anastomosis, urethroplasty, and perineal urethrostomy]. It should also be noted that with any of the treatment options, recurrence tends to happen. Especially with long strictures and previously treated ones.[15]

Urethral dilation using sounds and boogies has been the standard and initial treatment modality for a long time. Inserting urethral dilators and sequentially increasing the size leads to stretch and disruption of the stricture. When compared to direct vision internal urethrotomy, there was no demonstrable difference between them with regards to outcomes.[8][18][19] The need for re-treatment within three years for both is around 65%.[20] This procedure is usually performed under local anesthesia and can cause significant discomfort and bleeding. Some studies suggest that the use of balloon dilation would exert a radial force reducing urethral trauma. Initial numbers are pointing towards fewer recurrence rates compared to the previous methods. Sometimes it can be used as a regular dilatation of the urethra using the sounds or the catheter as clean intermittent self-catheterization [CISC] following the internal visual urethrotomy.[20]

Direct vision internal urethrotomy [DVIU] is performed by incising a transurethral incision to release the stricture and leave it to heal by secondary intention, increasing the caliber size of the urethra. It is the first-line treatment of choice for short [