Diagnosis and Treatment Overview © 1991 Karger AG, Basel 0302-2838/91/0206-0036 $2.75/0
Eur Urol 1991;20(suppl 2):36-40
Benign Prostatic Hyperplasia: Symptoms and Objective Interpretation J.T. Andersen Department of Urology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark 1605954
Key Words. Benign prostatic hyperplasia • Prostatism • Intravesical obstruction • Urodynamic effect parameters Abstract. Considerable new knowledge about benign prostatic hyperplasia has been gained over the past two de cades, particularly with regard to its natural history, hydrodynamic changes in the lower urinary tract, and the symp tomatic and urodynamic results of treatment. A survey of the literature has been undertaken with special attention to the results of interventional studies and suggestions for future research.
Benign prostatic hyperplasia (BPH), a process related to aging, is the most common cause of bladder outlet ob struction in men. The etiology of BPH is still unknown, but autopsy studies have documented histopathologic changes of nodular hyperplasia in more than 70% of men aged 70 years or older [1, 2]. However, only 10-25% of elderly men develop symptoms and signs of obstructive BPH that necessitate prostatectomy [3, 4], Thus, the prostate can undergo hyperplastic growth without giving rise to symptoms or signs requiring medical attention (fig-1)Healthy elderly men without subjective voiding symp toms or signs of obstructive BPH do, however, expe rience changes in bladder and urethral function. To a cer tain extent, these changes overlap those seen in BPH, and this overlap represents one of the major problems in inter ventional studies of patients with obstructive BPH. An other problem is the paucity of information on the natural history of untreated, symptomatic BPH over longer peri ods of time. This lack of knowledge certainly complicates the design and interpretation of interventional studies in
BPH, with regard to both surgery and pharmacologic treatment. The importance of these problems is underscored by the continuing increase in the elderly male population, with a consequent increase in the number of prostatecto mies. In 1978, 297,000 prostatectomies were performed in the United States [5]. This number has since increased to over 350,000, representing a considerable workload and expenditure for the health services. This survey pro vides a summary of our current knowledge of the symp tomatic and urodynamic changes in BPH, with special emphasis on interventional studies.
Symptoms Voiding symptoms may occur when the growing pros tate alters the conductivity of the prostatic urethra, caus ing subsequent changes in bladder and urethral function. The term prostatism denotes a syndrome with irritative and obstructive voiding symptoms traditionally related to obstructive BPH [6]. The irritative symptoms are fre quency, nocturia, urgency, urge incontinence, small void-
Downloaded by: University of Exeter 144.173.6.94 - 6/7/2020 10:49:45 PM
Introduction
BPH - Symptoms, Urodynamics, Natural History
MALE AGING
AGE
BPH
upros1]/
VTATISM / Fig. l. Schematic diagram of the relation between male aging, development of benign prostatic hyperplasia (BPH), and the occur rence of prostatism symptoms. Areas of overlap in Venn diagram are arbitrary.
BPH
IRRITATIVE SYMPTOMS
OBSTRUCTIVE SYMPTOMS
INFRAVESICAL OBSTRUCTION
SURGERY FOR BPH Fig. 2. Venn diagram showing relations between irritative and obstructive prostatism symptoms and urodynamically documented intravesical obstruction in benign prostatic hyperplasia (BPH). Areas of overlap are arbitrary.
In conclusion, assessment of BPH symptoms must be quantitated using a symptom score and verified by a fre quency/volume chart, the most precise and objective parameters in the study of the symptomatic effects of treatment of BPH.
Natural History The symptoms of BPH fluctuate considerably over time. In a retrospective study, Clarke [15] found that sub jective improvement lasted a mean of 1.9 years in 25 of 36 patients with mild BPH. Nine of 15 patients with severe BPH noted improvement that lasted 1.5 years on average. More recently, 26 patients with obstructive BPH were followed prospectively by Birkhoff et al. [16] for 3 years. Control parameters were a subjective symptom score and
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ed volumes, and suprapubic pain. The obstructive symp toms are hesitancy, weak stream, prolonged voiding time, straining, a feeling of incomplete bladder emptying, post micturition dribble, and total urinary retention. Despite its traditional relationship to BPH, prostatism is not always linked to the presence of bladder outflow obstruction due to that pathology (fig. 2). It has been demonstrated that 25-33% of patients with prostatism and palpable BPH have unobstructed micturition [6, 7]. Further, disturbances of the complex innervation of the lower urinary tract often give rise to dysfunctions with symptoms and hydrodynamic changes that are difficult to distinguish from obstructive BPH, e.g. parkinsonism [8], which has a high prevalence among elderly men. Healthy elderly men of the ‘prostatic age’ (60-90 years) who claim to have a normal voiding pattern also demonstrate a high prevalence of prostatism symptoms that are apparently considered to be physiologic rather than pathologic [9]In obstructive BPH, irritative symptoms are good indi cators of the presence of detrusor reflex instability but are unrelated to the severity of urodynamically proven blad der outflow obstruction [10]. Conversely, the presence of obstructive prostatic symptoms has been demonstrated to correlate reasonably well with the presence of bladder outflow obstruction - but also with primary underactive detrusor function. Thus, the indication for treatment of BPH cannot be based on symptom analysis alone in the absence of mandatory indications for surgery (e.g. repeated urinary retention, postrenal uremia): instead, objective demonstration of intravesical obstruction due to BPH is required. The aim of surgery or other treatment modalities for obstructive BPH is to relieve intravesical obstruction and the associated symptoms. Relying on subjective assess ments of improvement, unchanged condition, or deterio ration to assess symptomatic relief after treatment for BPH is subject to bias and should be abandoned. A fre quency/volume chart over 24 hours or several days affords a more accurate assessment of symptomatic change [11]. The International Continence Society considers the fre quency/volume chart a specific urodynamic investigation useful in both the assessment of voiding disorders and the follow-up of treatment [12]. BPH symptoms may also be quantitated by a symptom score using a numeric grading of individual symptoms [13]. Several grading systems that assign different weights to individual symptoms and that also include paraclinical parameters in the scoring system have been proposed [14]-
37
Andersen
38
DOCTOR
large. Detrusor reflex instability and changes in pressure/ flow parameters seem to occur with the same incidence in healthy elderly males as in patients with prostatism [6], a factor that should be considered when populations with BPH are studied. However, urodynamic studies are essential to assess the presence or absence of infravesical obstruction in BPH and to grade infravesical obstruction, when present.
DOCTOR
DOCTOR ♦
t
FLOW RATE
1
2
3
YEARS
Fig. 3. Schematic illustration of the natural history of symptoms and maximum flow rate in benign prostatic hyperplasia (BPH) over years. ‘Doctor’ denotes that the patient seeks medical attention.
an objective score based on maximum flow rate, residual urine, renal function, and prostatic size (palpation). Con siderable variation was registered in both subjective and objective parameters, with eight of 26 patients improving subjectively and four of 26 improving objectively. Dete rioration was slow and fluctuating. Figure 3 illustrates these findings. In a larger series of 97 BPH patients, in whom surgery was primarily deferred on clinical grounds, 84% had unchanged or improved symptomatology over 5 years [17]. The changes in both irritative and obstructive symp toms were similar when separated by category. These studies of the natural history of untreated BPH, although limited, seem to explain the extremely high placebo effect in previous studies of the symptomatic effects of various drugs on BPH [18, 19]. These results further stress the need for adequate length of treatment and follow-up when the effects of medical management of BPH are being studied. They also seem to justify a ran domized study of the effect of transurethral prostatec tomy compared with follow-up alone in patients with mild symptoms.
Urodynamic Implications Several urodynamic parameters seem to change with age. Thus, both maximum flow rate and voided volume were found to decrease with age in a population study of 93 asymptomatic healthy males of the prostatic age (median, 64 years; range, 50-92) [20]. Mean maximum flow rate was below 15 mL/s after age 60, with a general decline until the age of 80. However, the ranges were
Uroflowmetry During the last two decades, uroflowmetry has achieved an indisputable role in the assessment of infra vesical obstruction in patients with symptomatic BPH. According to Abrams and Griffiths [21], a maximum flow rate exceeding 15 mL/s generally indicates unobstructed micturition, whereas values below 10 mL/s indicate infra vesical obstruction, provided detrusor insufficiency is absent. This concept has two principal limitations. First, patients with a maximum flow rate exceeding 15 mL/s may have high-flow infravesical obstruction, a condition found in 5% of men hospitalized for prostatic symptoms [22]. Thus, in the presence of prostatic symptoms, pressure/ flow studies should be performed to establish this diagno sis, even when the flow rate is normal. Second, patients with prostatism and maximum flow rates between 10 and 15 mL/s should be investigated fur ther with pressure/flow studies in order to confirm or exclude the presence of infravesical obstruction. Uroflowmetry is easy to perform, noninvasive, and mandatory as a screening procedure in patients with symptomatic BPH. Since its reproducibility has been shown to be reasonably good [13], one or two flow studies may be sufficient in daily clinical practice, provided the patient has a normal desire to void and that the voided volume exceeds 150 mL. Residual Urine It has been suggested [21] and confirmed [10, 23] that the amount of residual urine in BPH reflects detrusor dys function rather than infravesical obstruction. Thus, the opening pressure and the maximum micturition pressure, both of which reflect detrusor pressure and abdominal straining, were found to correlate with the residual urine volume [10]. Further, the contribution of abdominal straining correlated with the residual urine volume. This implies that residual urine reflects the condition of the detrusor muscle, which may be impaired by other condi tions, such as autonomic neuropathy. A large intraindividual variation in residual urine vol ume has been found on repeated measurements in
Downloaded by: University of Exeter 144.173.6.94 - 6/7/2020 10:49:45 PM
SYMPTOM SCORE
BPH - Symptoms, Urodynamics. Natural History
Cystometry The prevalence of detrusor reflex instability in popula tions with prostatism is 50-60% [6]. However, a similar prevalence has been found in healthy elderly males in the prostatic age group [9]. Whether age-related changes, i.e. deficient detrusor reflex control, are due to incipient infravesical obstruc tion, impaired spinocerebral control of the detrusor reflex centers, or combinations thereof is still unclear. Further more, the result of preoperative cystometry does not in any way predict the symptomatic outcome of surgery for BPH [6,13], Thus, cystometry must be considered super fluous in the routine diagnostic workup of patients with symptomatic BPH. Pressure/Flow Studies The main indications for pressure/flow studies in symp tomatic BPH are flow rates between 10 and 15 mL/s [13] and suspicion of high-flow infravesical obstruction. Fur ther analysis of pressure/flow parameters by computerassisted calculation of the urethral resistance relation [25] has a significant prognostic value for the results of surgery for BPH [13]. However, such analyses are rather compli cated for routine use and must still be regarded as investi gative.
Prostatic Size The size of the prostate estimated by weight or volume has no relation per se to the presence or severity of infra vesical obstruction. Thus, the gland may be considerably enlarged without giving rise to infravesical obstruction, whereas small glands may induce significant bladder outlet obstruction. This reflects the fact that the anatomic distortion of the prostatic urethra determines alteration of urethral conductance. Nonetheless, prostatic size may be a relevant param eter in interventional surgical or pharmacologic studies of BPH. Digital rectal examination has been shown to be highly unreliable in the assessment of prostate weight [26] ; transrectal ultrasonic scanning has been shown to be very precise [27], and must be considered the technique of choice for studies of BPH that consider the size of the gland as a critical parameter.
Future Research A major problem in the preoperative evaluation of BPH is identification of the 10-15% of patients who will experience an unfavorable outcome following prostatic surgery [13], As yet, conventional urodynamic studies have not solved this problem. Future investigations should focus on patients with only mild symptoms. In light of the morbidity and mortality associated with prostatec tomy, at present it is not clear whether surgical treatment is indicated at all for such patients. The place of the medical treatment of this group of patients must also be established by means of well-con ducted, placebo-controlled studies using relevant effect parameters to assess treatment effect, adequate drug doses, and sufficiently long treatment and follow-up periods to exclude changes due to the natural history of the disease. Coexistent neurologic disorders in patients with BPH, e.g. parkinsonism and cerebrovascular disor ders, also present a diagnostic and therapeutic challenge. Generally, although these patients undergo comprehen sive urodynamic testing prior to treatment, their post operative outcome is less favorable than that of patients with normal detrusor function [28]. The future manage ment of this patient group also awaits further research.
Summary BPH is found in the majority of males aged 70 years or more. However, only 10-20% of elderly men develop symptoms and signs of obstructive BPH leading to prosta tectomy. The common term for the whole spectrum of symptoms is prostatism, which may or may not be associ ated with the presence of bladder outflow obstruction due to BPH. Obstructive symptoms, such as hesitancy, slow stream, straining, and incomplete bladder emptying, must be verified by urodynamic studies, primarily uroflowmetry and pressure/flow studies. Objective assess ment of both irritative and obstructive prostatic symp toms is mandatory in the evaluation of all treatment modalities for BPH.
References 1 Franks LM: Benign nodular hyperplasia of the prostate. Ann R Coll Surg 1954;14:92-106. 2 Berry SJ, Coffey DS, Walsh PC. et al: The development of human benign prostatic hyperplasia with age. J Urol 1984;132'474-479.
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patients with BPH [24], Thus, determination of residual urine volume has no place in the workup or management of patients with BPH, provided suspicion of coexistent neuropathic detrusor dysfunction can be excluded.
39
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40
18 Caine M. Perlberg S, Gordon R: The treatment of benign prostatic hypertrophy with flutamide (SCH 13521) - a placebo-controlled study. J Urol 1975;114:564-568. 19 Abrams PH: A double blind trial of the effects of candicin on patients with benign prostatic hypertrophy. Br J Urol 1977:49: 67-71. 20 Jprgensen JB, Jensen K-ME. Bille-Brahe NE: Uroflowmetry in asymptomatic elderly males. Br J Urol 1986:58:390-395. 21 Abrams PH, Griffiths DJ: The assessment of prostatic obstruction from urodynamic measurements and from residual urine. Br J Urol 1979;51:129-134. 22 Gerstenberg TC, Andersen JT, Klarskov P, et al: High flow infravesical obstruction in the male. J Urol 1982;127:943-945. 23 Gammelgaard PA. Andersen JT, Meyhoff HH: Clinical signif icance of urodynamic measurements, in Hinman F, Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983. pp 502-506. 24 Bruskewitz RC, Iversen P, Madsen PO: The value of postvoid residual urine determination in evaluation of prostatism. Urology 1982;20:602-604. 25 Shafer W: The contribution of the bladder outlet to the relation between pressure and flow rate during micturition, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983, pp 470—196. 26 Meyhoff HH, Haid T: Are doctors able to assess prostatic size? Scand J Urol Nephrol 1978;12:219-221. 27 Hastak SM, Gammelgaard J, Holm HH: Transrectal ultrasonic determination of the prostate - a preoperative and postoperative study. J Urol 1975:127:1115-1118. 28 Cass AS: Prostatectomy in vesical neurological disturbances, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983, pp 776-781.
Jens Thorup Andersen, MD, PhD Department of Urology Hvidovre University Hospital DK-2650 Hvidovre (Denmark)
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3 Lytton B, Emery JM, Harvard BM: The incidence of benign pros tatic obstruction. J Urol 1968;99:639-645. 4 Birkhoff JD: Natural history of benign prostatic hypertrophy, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York. Springer-Verlag, 1983. pp 5-9. 5 Vital and Health Statistics - Utilization of Short Stay Hospitals. Series 13, No 46. US Department of Health, Education and Wel fare publication No. (PHS) 80-1797, 1980. 6 Andersen JT: Prostatism: Clinical, radiological and urodynamic aspects. Neurourol & Urodynam 1982:1:241-293. 7 Abrams PH, Feneley RCL: The significance of the symptoms asso ciated with bladder outflow obstruction. Urol Int 1978;33: 171-174. 8 Andersen JT, Bradley WE: Cystometnc, sphincter and clectromyelographic findings in Parkinson’s disease. J Urol 1976; 116: 75-78. 9 Andersen JT, Jacobsen O. Worm-Petersen J. et al: Bladder func tion in healthy elderly males. Scand J Urol Nephrol 1978;12: 123-127. 10 Andersen JT, Nordling J, Walter S: Prostatism I: The correlation between symptoms, cystometnc and urodynamic findings. Scand J Urol Nephrol 1979;13:229-236. 11 Claridge M: Assessment of medical treatment, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983, pp 308-312. 12 Abrams P, Blaivas JG, Stanton S, et al: The standardization of ter minology of lower urinary tract function. Scand J Urol Nephrol 1988;114(suppl):5-19. 13 Jensen K-ME: Clinical evaluation of routine urodynamic investiga tions in prostatism. Neurourol & Urodynam 1989;8:545-578. 14 Madsen PO, Iversen P: A point system for selecting operative can didates, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hyper trophy. New York, Springer-Verlag, 1983, pp 763-765. 15 Clarke R: The prostate and the endocrines: A control series. Br J Urol 1937:9:254-271. 16 Birkhoff JD, Wiederhorn AR, Hamilton ML, et al: Natural history of benign prostatic hypertrophy and acute urinary retention. Urol ogy 1976;7:48-52. 17 Ball AJ, Feneley RCL, Abrams PH: The natural history of un treated ‘prostatism’. Br J Urol 1981:53:613-616.
Eur Urol 1991;20(suppl 2):36-40
Benign Prostatic Hyperplasia: Symptoms and Objective Interpretation J.T. Andersen Department of Urology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark 1605954
Key Words. Benign prostatic hyperplasia • Prostatism • Intravesical obstruction • Urodynamic effect parameters Abstract. Considerable new knowledge about benign prostatic hyperplasia has been gained over the past two de cades, particularly with regard to its natural history, hydrodynamic changes in the lower urinary tract, and the symp tomatic and urodynamic results of treatment. A survey of the literature has been undertaken with special attention to the results of interventional studies and suggestions for future research.
Benign prostatic hyperplasia (BPH), a process related to aging, is the most common cause of bladder outlet ob struction in men. The etiology of BPH is still unknown, but autopsy studies have documented histopathologic changes of nodular hyperplasia in more than 70% of men aged 70 years or older [1, 2]. However, only 10-25% of elderly men develop symptoms and signs of obstructive BPH that necessitate prostatectomy [3, 4], Thus, the prostate can undergo hyperplastic growth without giving rise to symptoms or signs requiring medical attention (fig-1)Healthy elderly men without subjective voiding symp toms or signs of obstructive BPH do, however, expe rience changes in bladder and urethral function. To a cer tain extent, these changes overlap those seen in BPH, and this overlap represents one of the major problems in inter ventional studies of patients with obstructive BPH. An other problem is the paucity of information on the natural history of untreated, symptomatic BPH over longer peri ods of time. This lack of knowledge certainly complicates the design and interpretation of interventional studies in
BPH, with regard to both surgery and pharmacologic treatment. The importance of these problems is underscored by the continuing increase in the elderly male population, with a consequent increase in the number of prostatecto mies. In 1978, 297,000 prostatectomies were performed in the United States [5]. This number has since increased to over 350,000, representing a considerable workload and expenditure for the health services. This survey pro vides a summary of our current knowledge of the symp tomatic and urodynamic changes in BPH, with special emphasis on interventional studies.
Symptoms Voiding symptoms may occur when the growing pros tate alters the conductivity of the prostatic urethra, caus ing subsequent changes in bladder and urethral function. The term prostatism denotes a syndrome with irritative and obstructive voiding symptoms traditionally related to obstructive BPH [6]. The irritative symptoms are fre quency, nocturia, urgency, urge incontinence, small void-
Downloaded by: University of Exeter 144.173.6.94 - 6/7/2020 10:49:45 PM
Introduction
BPH - Symptoms, Urodynamics, Natural History
MALE AGING
AGE
BPH
upros1]/
VTATISM / Fig. l. Schematic diagram of the relation between male aging, development of benign prostatic hyperplasia (BPH), and the occur rence of prostatism symptoms. Areas of overlap in Venn diagram are arbitrary.
BPH
IRRITATIVE SYMPTOMS
OBSTRUCTIVE SYMPTOMS
INFRAVESICAL OBSTRUCTION
SURGERY FOR BPH Fig. 2. Venn diagram showing relations between irritative and obstructive prostatism symptoms and urodynamically documented intravesical obstruction in benign prostatic hyperplasia (BPH). Areas of overlap are arbitrary.
In conclusion, assessment of BPH symptoms must be quantitated using a symptom score and verified by a fre quency/volume chart, the most precise and objective parameters in the study of the symptomatic effects of treatment of BPH.
Natural History The symptoms of BPH fluctuate considerably over time. In a retrospective study, Clarke [15] found that sub jective improvement lasted a mean of 1.9 years in 25 of 36 patients with mild BPH. Nine of 15 patients with severe BPH noted improvement that lasted 1.5 years on average. More recently, 26 patients with obstructive BPH were followed prospectively by Birkhoff et al. [16] for 3 years. Control parameters were a subjective symptom score and
Downloaded by: University of Exeter 144.173.6.94 - 6/7/2020 10:49:45 PM
ed volumes, and suprapubic pain. The obstructive symp toms are hesitancy, weak stream, prolonged voiding time, straining, a feeling of incomplete bladder emptying, post micturition dribble, and total urinary retention. Despite its traditional relationship to BPH, prostatism is not always linked to the presence of bladder outflow obstruction due to that pathology (fig. 2). It has been demonstrated that 25-33% of patients with prostatism and palpable BPH have unobstructed micturition [6, 7]. Further, disturbances of the complex innervation of the lower urinary tract often give rise to dysfunctions with symptoms and hydrodynamic changes that are difficult to distinguish from obstructive BPH, e.g. parkinsonism [8], which has a high prevalence among elderly men. Healthy elderly men of the ‘prostatic age’ (60-90 years) who claim to have a normal voiding pattern also demonstrate a high prevalence of prostatism symptoms that are apparently considered to be physiologic rather than pathologic [9]In obstructive BPH, irritative symptoms are good indi cators of the presence of detrusor reflex instability but are unrelated to the severity of urodynamically proven blad der outflow obstruction [10]. Conversely, the presence of obstructive prostatic symptoms has been demonstrated to correlate reasonably well with the presence of bladder outflow obstruction - but also with primary underactive detrusor function. Thus, the indication for treatment of BPH cannot be based on symptom analysis alone in the absence of mandatory indications for surgery (e.g. repeated urinary retention, postrenal uremia): instead, objective demonstration of intravesical obstruction due to BPH is required. The aim of surgery or other treatment modalities for obstructive BPH is to relieve intravesical obstruction and the associated symptoms. Relying on subjective assess ments of improvement, unchanged condition, or deterio ration to assess symptomatic relief after treatment for BPH is subject to bias and should be abandoned. A fre quency/volume chart over 24 hours or several days affords a more accurate assessment of symptomatic change [11]. The International Continence Society considers the fre quency/volume chart a specific urodynamic investigation useful in both the assessment of voiding disorders and the follow-up of treatment [12]. BPH symptoms may also be quantitated by a symptom score using a numeric grading of individual symptoms [13]. Several grading systems that assign different weights to individual symptoms and that also include paraclinical parameters in the scoring system have been proposed [14]-
37
Andersen
38
DOCTOR
large. Detrusor reflex instability and changes in pressure/ flow parameters seem to occur with the same incidence in healthy elderly males as in patients with prostatism [6], a factor that should be considered when populations with BPH are studied. However, urodynamic studies are essential to assess the presence or absence of infravesical obstruction in BPH and to grade infravesical obstruction, when present.
DOCTOR
DOCTOR ♦
t
FLOW RATE
1
2
3
YEARS
Fig. 3. Schematic illustration of the natural history of symptoms and maximum flow rate in benign prostatic hyperplasia (BPH) over years. ‘Doctor’ denotes that the patient seeks medical attention.
an objective score based on maximum flow rate, residual urine, renal function, and prostatic size (palpation). Con siderable variation was registered in both subjective and objective parameters, with eight of 26 patients improving subjectively and four of 26 improving objectively. Dete rioration was slow and fluctuating. Figure 3 illustrates these findings. In a larger series of 97 BPH patients, in whom surgery was primarily deferred on clinical grounds, 84% had unchanged or improved symptomatology over 5 years [17]. The changes in both irritative and obstructive symp toms were similar when separated by category. These studies of the natural history of untreated BPH, although limited, seem to explain the extremely high placebo effect in previous studies of the symptomatic effects of various drugs on BPH [18, 19]. These results further stress the need for adequate length of treatment and follow-up when the effects of medical management of BPH are being studied. They also seem to justify a ran domized study of the effect of transurethral prostatec tomy compared with follow-up alone in patients with mild symptoms.
Urodynamic Implications Several urodynamic parameters seem to change with age. Thus, both maximum flow rate and voided volume were found to decrease with age in a population study of 93 asymptomatic healthy males of the prostatic age (median, 64 years; range, 50-92) [20]. Mean maximum flow rate was below 15 mL/s after age 60, with a general decline until the age of 80. However, the ranges were
Uroflowmetry During the last two decades, uroflowmetry has achieved an indisputable role in the assessment of infra vesical obstruction in patients with symptomatic BPH. According to Abrams and Griffiths [21], a maximum flow rate exceeding 15 mL/s generally indicates unobstructed micturition, whereas values below 10 mL/s indicate infra vesical obstruction, provided detrusor insufficiency is absent. This concept has two principal limitations. First, patients with a maximum flow rate exceeding 15 mL/s may have high-flow infravesical obstruction, a condition found in 5% of men hospitalized for prostatic symptoms [22]. Thus, in the presence of prostatic symptoms, pressure/ flow studies should be performed to establish this diagno sis, even when the flow rate is normal. Second, patients with prostatism and maximum flow rates between 10 and 15 mL/s should be investigated fur ther with pressure/flow studies in order to confirm or exclude the presence of infravesical obstruction. Uroflowmetry is easy to perform, noninvasive, and mandatory as a screening procedure in patients with symptomatic BPH. Since its reproducibility has been shown to be reasonably good [13], one or two flow studies may be sufficient in daily clinical practice, provided the patient has a normal desire to void and that the voided volume exceeds 150 mL. Residual Urine It has been suggested [21] and confirmed [10, 23] that the amount of residual urine in BPH reflects detrusor dys function rather than infravesical obstruction. Thus, the opening pressure and the maximum micturition pressure, both of which reflect detrusor pressure and abdominal straining, were found to correlate with the residual urine volume [10]. Further, the contribution of abdominal straining correlated with the residual urine volume. This implies that residual urine reflects the condition of the detrusor muscle, which may be impaired by other condi tions, such as autonomic neuropathy. A large intraindividual variation in residual urine vol ume has been found on repeated measurements in
Downloaded by: University of Exeter 144.173.6.94 - 6/7/2020 10:49:45 PM
SYMPTOM SCORE
BPH - Symptoms, Urodynamics. Natural History
Cystometry The prevalence of detrusor reflex instability in popula tions with prostatism is 50-60% [6]. However, a similar prevalence has been found in healthy elderly males in the prostatic age group [9]. Whether age-related changes, i.e. deficient detrusor reflex control, are due to incipient infravesical obstruc tion, impaired spinocerebral control of the detrusor reflex centers, or combinations thereof is still unclear. Further more, the result of preoperative cystometry does not in any way predict the symptomatic outcome of surgery for BPH [6,13], Thus, cystometry must be considered super fluous in the routine diagnostic workup of patients with symptomatic BPH. Pressure/Flow Studies The main indications for pressure/flow studies in symp tomatic BPH are flow rates between 10 and 15 mL/s [13] and suspicion of high-flow infravesical obstruction. Fur ther analysis of pressure/flow parameters by computerassisted calculation of the urethral resistance relation [25] has a significant prognostic value for the results of surgery for BPH [13]. However, such analyses are rather compli cated for routine use and must still be regarded as investi gative.
Prostatic Size The size of the prostate estimated by weight or volume has no relation per se to the presence or severity of infra vesical obstruction. Thus, the gland may be considerably enlarged without giving rise to infravesical obstruction, whereas small glands may induce significant bladder outlet obstruction. This reflects the fact that the anatomic distortion of the prostatic urethra determines alteration of urethral conductance. Nonetheless, prostatic size may be a relevant param eter in interventional surgical or pharmacologic studies of BPH. Digital rectal examination has been shown to be highly unreliable in the assessment of prostate weight [26] ; transrectal ultrasonic scanning has been shown to be very precise [27], and must be considered the technique of choice for studies of BPH that consider the size of the gland as a critical parameter.
Future Research A major problem in the preoperative evaluation of BPH is identification of the 10-15% of patients who will experience an unfavorable outcome following prostatic surgery [13], As yet, conventional urodynamic studies have not solved this problem. Future investigations should focus on patients with only mild symptoms. In light of the morbidity and mortality associated with prostatec tomy, at present it is not clear whether surgical treatment is indicated at all for such patients. The place of the medical treatment of this group of patients must also be established by means of well-con ducted, placebo-controlled studies using relevant effect parameters to assess treatment effect, adequate drug doses, and sufficiently long treatment and follow-up periods to exclude changes due to the natural history of the disease. Coexistent neurologic disorders in patients with BPH, e.g. parkinsonism and cerebrovascular disor ders, also present a diagnostic and therapeutic challenge. Generally, although these patients undergo comprehen sive urodynamic testing prior to treatment, their post operative outcome is less favorable than that of patients with normal detrusor function [28]. The future manage ment of this patient group also awaits further research.
Summary BPH is found in the majority of males aged 70 years or more. However, only 10-20% of elderly men develop symptoms and signs of obstructive BPH leading to prosta tectomy. The common term for the whole spectrum of symptoms is prostatism, which may or may not be associ ated with the presence of bladder outflow obstruction due to BPH. Obstructive symptoms, such as hesitancy, slow stream, straining, and incomplete bladder emptying, must be verified by urodynamic studies, primarily uroflowmetry and pressure/flow studies. Objective assess ment of both irritative and obstructive prostatic symp toms is mandatory in the evaluation of all treatment modalities for BPH.
References 1 Franks LM: Benign nodular hyperplasia of the prostate. Ann R Coll Surg 1954;14:92-106. 2 Berry SJ, Coffey DS, Walsh PC. et al: The development of human benign prostatic hyperplasia with age. J Urol 1984;132'474-479.
Downloaded by: University of Exeter 144.173.6.94 - 6/7/2020 10:49:45 PM
patients with BPH [24], Thus, determination of residual urine volume has no place in the workup or management of patients with BPH, provided suspicion of coexistent neuropathic detrusor dysfunction can be excluded.
39
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18 Caine M. Perlberg S, Gordon R: The treatment of benign prostatic hypertrophy with flutamide (SCH 13521) - a placebo-controlled study. J Urol 1975;114:564-568. 19 Abrams PH: A double blind trial of the effects of candicin on patients with benign prostatic hypertrophy. Br J Urol 1977:49: 67-71. 20 Jprgensen JB, Jensen K-ME. Bille-Brahe NE: Uroflowmetry in asymptomatic elderly males. Br J Urol 1986:58:390-395. 21 Abrams PH, Griffiths DJ: The assessment of prostatic obstruction from urodynamic measurements and from residual urine. Br J Urol 1979;51:129-134. 22 Gerstenberg TC, Andersen JT, Klarskov P, et al: High flow infravesical obstruction in the male. J Urol 1982;127:943-945. 23 Gammelgaard PA. Andersen JT, Meyhoff HH: Clinical signif icance of urodynamic measurements, in Hinman F, Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983. pp 502-506. 24 Bruskewitz RC, Iversen P, Madsen PO: The value of postvoid residual urine determination in evaluation of prostatism. Urology 1982;20:602-604. 25 Shafer W: The contribution of the bladder outlet to the relation between pressure and flow rate during micturition, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983, pp 470—196. 26 Meyhoff HH, Haid T: Are doctors able to assess prostatic size? Scand J Urol Nephrol 1978;12:219-221. 27 Hastak SM, Gammelgaard J, Holm HH: Transrectal ultrasonic determination of the prostate - a preoperative and postoperative study. J Urol 1975:127:1115-1118. 28 Cass AS: Prostatectomy in vesical neurological disturbances, in Hinman F Jr, Boyarsky S (eds): Benign Prostatic Hypertrophy. New York, Springer-Verlag, 1983, pp 776-781.
Jens Thorup Andersen, MD, PhD Department of Urology Hvidovre University Hospital DK-2650 Hvidovre (Denmark)
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