What is the most appropriate technique to determine the cause of a tender and edematous prepuce in a 68-year-old man with decreased urine output and a history of neurogenic bladder?

From the Guidelines

The most appropriate technique to determine the cause of a tender and edematous prepuce in this 68-year-old man with decreased urine output and neurogenic bladder is urethral catheterization. This patient's presentation strongly suggests urinary retention with possible balanitis or paraphimosis as complications. A urethral catheter (preferably 14-16 French Foley catheter) should be inserted to relieve the obstruction and allow for measurement of post-void residual volume. Prior to insertion, the genital area should be cleaned with antiseptic solution, and sterile technique must be maintained throughout the procedure. If catheterization is difficult due to preputial edema, gentle manual reduction of the edema may be necessary first. Once the catheter is placed, the initial urine output should be measured and monitored, with volumes exceeding 1 liter drained slowly to prevent post-obstructive diuresis. The catheter should remain in place until the underlying cause is addressed. This approach is indicated because neurogenic bladder predisposes to urinary retention, which can lead to proximal urethral distention, causing preputial edema and tenderness. Prompt catheterization not only diagnoses the condition but also provides immediate therapeutic benefit by relieving the obstruction and preventing further complications such as acute kidney injury or urinary tract infection, as suggested by the guidelines on adult neurogenic lower urinary tract dysfunction diagnosis and evaluation 1.

The patient's symptoms, including decreased urine output, are consistent with urinary retention, which is a common complication in patients with neurogenic bladder, as noted in the guidelines on adult neurogenic lower urinary tract dysfunction treatment and follow-up 1. The presence of a tender and edematous prepuce further supports the diagnosis of urinary retention with possible balanitis or paraphimosis.

In terms of diagnosis, the guidelines on urethral stricture disease amendment (2023) suggest that urethral stricture should be included in the differential diagnosis of patients who present with decreased urinary stream, incomplete emptying, dysuria, urinary tract infection, and rising post-void residual 1. However, in this case, the patient's presentation is more consistent with urinary retention due to neurogenic bladder rather than urethral stricture.

The guidelines on urinary infection management in frail or comorbid older individuals (2024) provide guidance on the diagnosis and treatment of urinary tract infections, but do not specifically address the diagnosis of urinary retention or urethral stricture 1. The European Association of Urology guidelines on urological infections (2024) also provide guidance on the diagnosis and treatment of urinary tract infections, but do not specifically address the diagnosis of urinary retention or urethral stricture 1.

Overall, the most appropriate technique to determine the cause of a tender and edematous prepuce in this 68-year-old man with decreased urine output and neurogenic bladder is urethral catheterization, as it provides both diagnostic and therapeutic benefits.

From the Research

Determining the Cause of Physical Examination Findings

To determine the cause of a tender and edematous prepuce in a 68-year-old man with decreased urine output and a history of neurogenic bladder, the following techniques can be considered:

• Urinalysis: This includes physical, chemical, and microscopic examinations of the urine sample 2. A midstream clean collection is acceptable, but the specimen should be examined within two hours of collection.
• Dipstick urinalysis: Although convenient, false-positive and false-negative results can occur 2, 3. Specific gravity provides a reliable assessment of the patient's hydration status.
• Microscopic urinalysis: This is likely comparable to dipstick urinalysis as a screening test 3.
• Urine culture: This is the gold standard for detection of urinary tract infection 3. However, asymptomatic bacteriuria is common, particularly in older women, and should not be treated with antibiotics.

Considerations for Patients with Neurogenic Bladder

In patients with neurogenic bladder, the management of asymptomatic bacteriuria and urinary tract infections is crucial:

• Bladder irrigation has been evaluated as a means of treatment for bacteriuria in persons with neurogenic bladder, but no advantages were detected for neomycin-polymyxin or acetic acid over saline in terms of reducing the urinary bacterial load and inflammation 4.
• Inappropriate diagnosis and treatment of asymptomatic bacteriuria and urinary tract infection are leading causes of antibiotic overuse in patients with neurogenic bladder 5.
• Factors associated with inappropriate management include peripheral vascular disease, chronic kidney disease, and cerebrovascular disease, while indwelling catheter and Physical Medicine & Rehabilitation provider are associated with decreased odds of inappropriate management 5.