Male Lower Urinary Tract Symptoms and Assessment

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Male Lower Urinary Tract Symptoms and Assessment

Henry Tran,¹ Matthew P. Rutman,² Doreen E. Chung,³ & Jerry G. Blaivas⁴

¹ Department of Urology, Columbia University Medical Center, New York, NY, USA

² Columbia University, New York, NY, USA

³ Department of Urology, Female Pelvic Medicine & Reconstructive Surgery, Columbia University, New York, NY, USA

⁴ Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA

Introduction

Benign prostatic hyperplasia (BPH) is an age‐dependent pathoanatomic condition with an initial histopathologic development after 40 years of age, and prevalence rates of approximately 50% and 90% by 60 and 85 years of age, respectively. Cell proliferation associated with BPH is composed of both epithelial and stromal elements and may result in benign prostatic enlargement (BPE), bladder outlet obstruction (BOO), and a constellation of lower urinary tract symptoms (LUTS) that are commonly classified as voiding or storage symptoms.

In most instances, the patient has more than one complaint. It has generally been assumed that voiding symptoms are caused by prostatic obstruction and that storage symptoms are caused by inflammation or detrusor overactivity. Despite the logic implied, most clinical studies that document the relationship between symptoms and underlying pathophysiology have established no such correlation.

Although existing medical and surgical interventions attempt to reduce the obstructive component to provide symptomatic relief, the association between BPH, benign prostatic obstruction (BPO), and BOO is complex. For example, it is unclear whether urethral obstruction is the primary mechanism by which BPH causes symptoms. Nor is it known whether the relief of the obstruction is a prerequisite to successful treatment of symptoms. Likewise, the relationship between symptoms and commonly used indices (to measure LUTS suggestive of prostatism), such as uroflow and postvoid residual (PVR) urine, is unknown.

Recent evidence suggests that the etiology of prostatic symptoms is multifactorial involving (i) prostatic urethral obstruction, (ii) impaired detrusor contractility, and (iii) detrusor overactivity [1]. The best method to definitively diagnose BOO is the detrusor pressure–uroflow flow study (PFS), but there is much more to be obtained from urodynamics than simply diagnosing obstruction.

This chapter describes existing urodynamic techniques used in the diagnosis of BPH, and reviews the role of urodynamics in the evaluation of LUTS and urinary incontinence.

Background

LUTS are generally categorized into storage, voiding, and postmicturition symptoms [2]. Storage symptoms include daytime frequency, nocturia, urgency, and urinary incontinence. Voiding symptoms are composed of slow stream, splitting or spraying, hesitancy, intermittency, and straining to void. Postmicturition symptoms include feeling of incomplete emptying and postmicturition dribbling. In men, BOO associated with BPH is only one of many causes of LUTS. Other causes include overactive bladder (OAB), neurogenic bladder, impaired detrusor contractility, low bladder compliance, and polyuria. It is not possible to make the diagnosis of BOO on symptom assessment alone. In patients with LUTS and BPH, urodynamic evidence of BOO exists in only 50–66% of patients [3–6]. Furthermore, a number of studies have demonstrated a lack of correlation between symptoms, the American Urological Association (AUA) symptom score or the Danish Prostate Symptom Score, and urodynamic data in patients with suspected BPH and BOO [7–10].

Determining the urodynamic abnormalities responsible for LUTS is important so that treatment can be directed at the underlying pathophysiology. Currently, the majority of medical and surgical interventions target the reduction or elimination of prostatic obstruction, yet only about two‐thirds of men are actually obstructed according to urodynamic criteria. In fact, therapies should be specific for detrusor overactivity, urgency, and impaired detrusor contractility. Urodynamics are necessary to make the distinctions between these entities.

The most definitive method of diagnosing urethral obstruction and impaired detrusor contractility is the detrusor pressure–uroflow study, whereas only cystometry is necessary to assess urgency and detrusor overactivity. Although questionnaires, symptom analysis, uroflow, and postvoid residual urine volumes (PVR) all play a role in evaluating men with suspected BOO, only urodynamics can make the necessary distinctions to allow therapy to be tailored to the underlying condition.

Defining and quantifying symptoms

Defining and quantifying symptoms are important for two reasons. First, there is an imperfect correlation between symptoms, symptom severity, bother, and underlying pathophysiology. It is therefore important to quantify each of these variables separately in order to tailor the treatment to the individual patient’s wants and needs. Second, in order to evaluate treatment outcomes in any meaningful way, it is necessary to tabulate this data before and after treatment (Table 140.1). There are numerous LUTS questionnaires and patient‐reported outcome instruments, but no single questionnaire contains all of the domains necessary to define and quantitate the necessary data for clinical care or outcomes research. In our judgment, the two best are the ICIQmale LUTS‐SF and the Lower Urinary Tract Symptom Score (LUTSS) [11, 12]. The latter is divided into six subscores: voiding, storage, OAB, incontinence, nocturia, and bother. It is also available as a mobile app that can be completed remotely by the patient and displayed in a graphic format that allows visual comparison of treatment outcomes (Figure 140.1).

Table 140.1 Relevant data before and after treatment.

Structured micturition history
Symptom severity score, such as the Lower Urinary Tract Symptom Score, American Urological Association symptom score, or ICIQmale LUTS
Physical examination, including:	General examination
	Brief screening neurologic examination (to discriminate normal, paraplegic, quadriplegic, hemiplegic, dementia, etc.)
	Focused meurologic examination (perianal sensation, anal sphincter tone and control, and bulbocavernosus reflex)
	Prostate examination
A micturition diary including:	Time of micturition
	Description of symptoms
	Voided volume
Uroflow (Q) and postvoid residual determination (PVR):	Urodynamic parameters: the following parameters permit patients to be objectively classified as having prostatic obstruction or impaired contractility:
	Maximum uroflow (Q_max)
	Detrusor pressure at maximum flow (P_det at Q_max)
	Other useful urodynamic parameters include:
	Presence or absence of detrusor overactivity
	Bladder sensation and ability to abort involuntary detrusor contractions
	Bladder capacity
	Voided volume

Image described by caption. — **Figure 140.1** Lower Urinary Tract Symptom Score (LUTSS) and bladder diary displayed via a mobile app. The patient is a 58‐year‐old man who presented with severe lower urinary tract symptoms. (a) Graphic representation of the LUTSS. The LUTSS is a 14‐question questionnaire composed of six subscores: voiding symptoms, storage symptoms, overactive bladder (OAB), incontinence, nocturia, and LUTS bother. All scores are normalized on a scale of 0–100 (100 is the worst possible symptoms). The top graph in blue was competed prior to TURP; the bottom one in brown three months postop shows dramatic improvement in all scores. (b) Twenty‐four‐hour bladder diary pre and post TURP. Abnormal values are in red.

Preparation for urodynamic study

The main purpose of urodynamic evaluation is to document the underlying cause of the patient’s complaints and to correlate symptoms with urodynamic findings. From a clinical standpoint, the purpose of urodynamic testing is to measure and record various physiologic variables while the patient is experiencing those symptoms that constitute his usual complaints. Thus, in this context, urodynamics should be considered to be a provocative test of vesicourethral function, and it is the responsibility of the examiner to ensure that the patient’s symptoms are reproduced during the study. To this end, it is important that the examiner has all relevant clinical information prior to and during the urodynamic study. For example, the examiner should have results of fairly extensive evaluation including (i) a focused history (including symptom questionnaire), (ii) focused physical examination, (iii) urinalysis ± culture, (iv) a 24‐hour bladder diary, (v) a 24‐hour pad test (for patients with incontinence), (vi) uroflow, and (vii) PVR.

Furthermore, in order to interpret urodynamic studies more accurately, the following information should be available to the examiner before the start of the study:

What symptoms are you trying to reproduce?
What is the functional bladder capacity (maximum voided volume on the voiding diary)?
What is the PVR?
What is the uroflow? (Is there likelihood of either urethral obstruction or impaired detrusor contractility?)
Is there a neurologic disorder that could cause neurogenic bladder?

The specifics of urodynamic techniques and parameters may confound the practicing physician, but in principle there are only five: cystometry, uroflow, leak point pressure, sphincter electromyography, and radiographic visualization of the lower urinary tract (if video is performed). Each technique may be performed alone or synchronously with one another. The tests are called multichannel urodynamics when done synchronously, and called video‐urodynamics when performed with fluoroscopic visualization of the lower urinary tract. In the following section, use of each urodynamic technique in the evaluation of lower urinary tract symptoms will be explained.

Evaluation of lower urinary tract symptoms

Voiding symptoms with uroflowmetry

In general, voiding symptoms have one or more of three basic underlying etiologies: BOO, impaired or absent detrusor contractility, and/or trying to void when there is insufficient bladder volume. BOO is characterized by a detrusor contraction of adequate magnitude (pressure) and duration, and a diminished flow. Impaired contractility is characterized by a weak or poorly sustained detrusor contraction and a low flow. If a patient tries to void when there is an insufficient bladder volume, it may be difficult for him to initiate the stream and the flow is likely to be low because of the well‐known correlation between bladder volume and urinary flow rate [13].

Uroflowmetry is a simple, objective, and noninvasive method to evaluate LUTS. Uroflowmetry is not used to evaluate filling symptoms. It should be performed in a private setting with the patient sitting or standing to reproduce normal voiding patterns. From simple uroflowmetry, the maximum urinary flow (Q_max), flow pattern, voided volume, and shape of flow curve can be obtained. After voiding, the PVR is recorded with ultrasound or catheterization if invasive urodynamics are to follow.

Uroflowmetry is best performed when the patient experiences a normal desire to void. A minimum urine volume of 150 ml provides an accurate study [13]. Existing nomograms provide values with age‐ and volume‐adjusted flow rate [7, 8, 14]. A Q_max of greater than 15 ml/s is considered normal, and approximately 95% of patients with this parameter will not be obstructed [15]. A Q_max of less than 10 ml/s is considered abnormal, and of 10–15 ml/s is equivocal [15]. However, it should be noted that uroflowmetry cannot distinguish a low flow due to outlet obstruction from that due to impaired detrusor contractility [16]. A variety of normal uroflow tracings with normal curves and parameters are shown in Figure 140.2. Normal flow patterns have a bell‐shaped curve, while patients with obstruction usually have a flattened curve. Interrupted flow patterns can be seen in patients with any of impaired bladder contractility, obstruction, or abdominal straining/voiding [17].

Image described by caption and surrounding text. — **Figure 140.2** Normal continuous uroflows. (a) Normal uroflow in a 52‐year‐old man. The pattern is continuous and the curve is very slightly fluctuating. Maximum flow (Q_max) = 31 ml/s; average flow rate (Q_ave) = 22 ml/s; voided volume = 269 ml; postvoid residual volume (PVR) = 0 ml. (b) Normal uroflow in a 53‐year‐old man. The pattern is continuous and the curve is fluctuating. Q_max = 24 ml/s; Q_ave = 13 ml/s; voided volume = 190 ml; PVR = 0 ml. (c) Normal uroflow in a 59‐year‐old man. The pattern is continuous and the curve is slightly fluctuating. Q_max = 15 ml/s; Q_ave = 10 ml/s; voided volume = 200 ml; PVR = 10 ml.

An equivocal uroflow may be seen in patients with significant obstruction and an abnormal flow may also be seen in those with poor detrusor function. It is obvious that BOO is usually accompanied by a low urinary flow rate, but a low flow may also be due to impaired detrusor contractility. In patients who are obstructed, uroflowmetry cannot differentiate between different types of urethral obstruction (BPH, urethral stricture, etc.). Figure 140.3 displays two similar abnormal uroflowmetry patterns despite their having different etiologies.

Despite these limitations, uroflowmetry remains a useful initial evaluation of men with LUTS. The AUA guidelines (2010; validated 2014) recommend uroflowmetry as an optional test in men with LUTS as initial diagnostic assessment or follow‐up assessment after treatment. Ideally two flow rates should be obtained and each should have a voided volume of >150 ml [18]. However, the European Association of Urology Guidelines on BPH recommend uroflowmetry in the assessment and diagnostic workup of men with LUTS and it is considered mandatory prior to surgical intervention [19]. We recommend uroflow for all men as part of the diagnostic evaluation of LUTS and as an outcome measure when evaluating response to treatment.

Filling symptoms with cystometry

Filling symptoms may be caused by detrusor overactivity, urgency, low bladder compliance, reduced bladder capacity, or polyuria. It is imperative to exclude other underlying causes of filling symptoms, such as urinary tract infection, bladder and prostate cancer, urolithiasis, and neurogenic bladder, prior to urodynamic testing. Polyuria can be caused by excessive fluid intake, diabetes mellitus, diabetes insipidus, and other less common conditions. Nocturia may be the result of abnormal drinking patterns, a reversal of the normal diurnal antidiuretic hormone cycle, congestive heart failure, venous insufficiency, sleep apnea, lower extremity edema, diabetes mellitus, or hypertension.

Filling cystometry is the only method that can document detrusor overactivity and low bladder compliance; however, it is not useful as a standalone procedure in men with LUTS. Currently, the AUA guidelines recommend that cystometry be done as part of the PFS. In men experiencing LUTS, up to two‐thirds may be found to have detrusor overactivity. Despite poor physiologic explanation, resolution of detrusor overactivity can be expected in 50–70% of patients after outlet reduction [20, 21]. Figure 140.4 demonstrates an idealized cystometrogram as well as an actual cystometrogram from a patient: note that without abdominal pressure tracings, the cause of vesical pressure increase cannot be determined accurately.

Multichannel urodynamics and video‐urodynamics

The simultaneous measurement and display of multiple urodynamic parameters is the most precise diagnostic tool for evaluating abnormalities of micturition. As described earlier, the addition of radiographic visualization of the lower urinary tract with multichannel urodynamics is termed video‐urodynamics. In these studies, radiographic contrast is used as the infusant for cystometry and other urodynamic parameters, including abdominal pressure, uroflow and sphincter electromyography, are recorded as well. By measuring multiple urodynamic variables, a better insight into the underlying pathophysiology is gained, as well as a better appreciation of their interrelationships and of artefacts. The International Continence Society has recommended standards for the performance of these studies [17, 22].

The main purpose of urodynamic evaluation is to recreate the patient’s complaints and to correlate symptoms to the urodynamic findings. Thus, it is essential to understand the nature of a patient’s complaints and to use the urodynamic evaluation as a provocative test to mimic those symptoms, as alluded to above. During the interactive process, the examiner should document whether or not the patient’s symptoms are reproduced and, if they are, the underlying cause should be clearly understood before completion of the study.

Urodynamic technique

A uroflow should be obtained prior to the urodynamic evaluation. Then, a 7 Fr double‐lumen bladder catheter and rectal balloon catheter are passed into the bladder and rectum, respectively, to measure vesical and abdominal pressure. PVR is measured via the urethral catheter. Proper calibration is imperative to produce an accurate and clinically meaningful evaluation. Pressure transducers are zeroed to atmospheric pressure at the level of the symphysis pubis. Newer air‐charged catheters have an air‐filled balloon placed around a polyethylene catheter. Pressure measurements are made directly from the balloon to the air‐filled catheter lumen and directly to the external pressure transducer; this conveniently eliminates the need for calibration to the symphysis pubis and flushing of the catheters, which was required in traditional fluid‐filled systems. During calibration the patient should be asked to cough or Valsalva to ensure proper reading of instruments on the computer display. Vesical pressure (P_ves) and abdominal pressure (P_abd) are measured directly from the urethral and rectal catheters and displayed on a computer screen. Detrusor pressure (P_det) is electronically calculated by subtracting P_abd from P_ves and displayed on a third channel. Other channels display sphincter electromyelogram (EMG), infused bladder volume, filling rate, voided volume, and uroflow. For video‐urodynamics, fluoroscopic images are sampled periodically as well as at times of events such as urgency and during voiding. Standard urodynamic parameters measured include bladder compliance (C = change in bladder volume (ΔV)/change in detrusor pressure (ΔP_det)), maximum detrusor pressure, detrusor pressure at maximum flow (P_detQ_max), and bladder capacity. Bladder compliance should be measured with starting point at initiation of bladder filling and endpoint at either cystometric capacity or immediately prior to any detrusor contraction causing leakage based on International Continence Society (ICS) recommendations [2, 23]. Normal bladder compliance should be greater than 20 ml/cmH₂O, but there is no consensus on a strict value of normal or impaired compliance [23, 24]. The range in normal compliance is likely because compliance is highly dependent on bladder capacity. Impaired compliance is typically accepted as any value <20 ml/cmH₂O, but more importantly should be interpreted based on clinical context. The important components of urodynamic evaluation include presence of involuntary detrusor contractions, incontinence episodes, sphincteric coordination, and activity during storage and emptying, and bladder sensation. Bladder sensation is assessed at three standard points: volume at first sensation of bladder filling, first sensation of urgency, and strong sensation of urgency [23].

Evaluation of filling symptoms

During bladder filling, the presence or absence of detrusor overactivity is noted and bladder compliance recorded. If detrusor overactivity is documented, the patient’s awareness, concern, and ability to contract the sphincter, abort the stream, and prevent incontinence are noted. These characteristics are used to classify the type of overactive bladder [25] (Figure 140.5).

Detrusor overactivity is seen in over 50% of patients with BPH, but its presence does not correlate with urethral obstruction [1, 26–28]. A patient with clinical BPH may have detrusor overactivity in the presence of prostatic obstruction, but even in the absence of prostatic obstruction, detrusor overactivity may cause obstructive symptoms. For example, a patient may develop involuntary bladder contraction at a relatively low bladder volume, which is perceived as an urge to void. The patient rushes to the bathroom, however, by this time the involuntary contraction has subsided and there is no longer an urge to void. Attempts to void by the patient with straining and pushing will be unsuccessful due to the small bladder volume. Thus, once it has been determined that there are overactive detrusor contractions, it is important to determine the degree of the patient’s awareness, concern, and control.

Evaluation of voiding symptoms

BOO and urethral resistance are defined by PFS parameters. The BOO index (BOOI) is used to measure the degree of obstruction. It is calculated using the following formula: