Benign prostate disease

51


Benign prostate disease




Outline



Objectives


Test Questions


Incidence and Prevalence


Risk Factors and Pathophysiology



Clinical Manifestations


BPH: Differential Diagnosis and Assessment


BPH: Management



Prostatitis: Differential Diagnosis and Assessment



Prostatitis: Management



Summary


Web Resources


Key References


References



Objectives


Upon completion of this chapter, the reader will be able to:


• Describe the clinical anatomy, physiology, and age-related changes of the prostate.


• Describe common lower urinary tract symptoms (LUTS) in an aging male.


• Know how to diagnose benign prostatic hyperplasia (BPH).


• Delineate the treatment options for BPH.


• Understand the framework for the diagnosis and treatment of prostatitis.



Incidence and prevalence


This chapter reviews the two common benign conditions of the prostate gland: benign prostatic hyperplasia (BPH) and prostatitis. With advancing age, the prevalence of prostate diseases increases dramatically. Self-reported prostate disease affects about 3 million American men. BPH develops in more than half of men age 65 or older and affects the overwhelming majority of men older than age 85. The prevalence of prostatitis is similar to that of ischemic heart disease or diabetes mellitus.



CASE 1   Paul Phillips (Part 1)


Paul Phillips is a 67-year-old man who comes to your office asking for “something to stop me from going so often.” He notes being unable to hold his urine for very long once he has an urge to void and arising three to four times each night to urinate. Some days he notes he is tired because voiding interferes with his sleep. He is concerned that the problem is interfering significantly with his daily golf game. He drinks diet cola about three times a day and has an evening cocktail four or five times a week.


His past medical history is remarkable for occasional constipation (he uses a stool softener two to three times a month), osteoarthritis of the knee which he manages with Tylenol extra strength two to three times a week, and bilateral cataracts for which he limits night driving. He takes a daily multivitamin and uses NoDoz alertness pills about four times a month when his sleep has been significantly interrupted.





Risk factors and pathophysiology



Overview of anatomy and physiology including age-related changes


The male lower urinary tract is composed of the urinary bladder, prostate, and urethra. The prostate gland is an accessory gland of the male reproductive system. The retroperitoneal organ is located anterior to the rectum and encircles the neck of the urinary bladder and part of the urethra. Its main function is to produce fluid for semen, which transports sperm. A healthy adult prostate is walnut shaped with an average size of 20 g.


Upon gross appearance, the prostate includes a base and an apex. The base of the prostate is near the inferior surface of the bladder and a large part of the base is continuous with the bladder wall. The apex or lower end of the prostate is adjacent to the external urethral sphincter.


The prostate is a collection of 30 to 50 irregularly shaped tubuloalveolar glands that open into the prostatic urethra via separate branching ducts. These glands are embedded in fibromuscular stroma, dense with collagen and irregularly arranged smooth muscle. The outer layer of the prostate is a thin, indistinct fibroelastic capsule mixed with smooth muscle. Age-related changes in the prostate, such as glandular enlargement, increased smooth muscle tone, and decreased compliance secondary to altered collagen deposition, can lead to urinary symptoms.


The prostate is divided into four lobes. The anterior lobe lies in front of the urethra and consists of fibromuscular tissue. The median lobe is situated between the two ejaculatory ducts and the urethra. The right and left lateral lobes make up the bulk of the prostate and are separated by the prostatic urethra. The posterior lobe is the medial part of the lateral lobes and can be palpated through the rectum during digital rectal examination (DRE).


The prostate can be divided histologically into three concentric zones: the peripheral zone (the outermost area of the prostate that constitutes 70% of the glandular tissue), the central zone (that represents 25% of the glandular tissue), and the transitional zone (the innermost area that rests next to the urethra and constitutes 5% of the glandular tissue). This distribution of zones has clinical significance. The peripheral zone is the area that is palpated on DRE, is most commonly affected by chronic prostatitis, and is where 70% of adenocarcinomas are found. Benign prostatic hyperplasia commonly arises in the transitional zone.


The white serous prostatic fluid contains acid phosphatase, citric acid, zinc, prostate-specific antigen (PSA), and other protease and fibrolytic enzymes involved in liquefaction of semen. With aging, there is an increase in the number and calcification of prostatic concretions (mixture of prostatic secretions and debris from degenerated epithelial cells). It is postulated that prostatic concretions serve as a nidus for development of chronic bacterial prostatitis.


The prostate is under neurohormonal influence; alpha-1 adrenergic receptors are the predominant type of adrenergic receptors present in the smooth muscle of the prostate and help maintain urethral tone and intraurethral pressure. Testosterone is converted to dihydrotestosterone (DHT) by 5-alpha-reductase in prostatic stromal cells. Androgen stimulation of glandular tissue via DHT contributes to the development and growth of the prostate gland and may lead to benign prostatic hyperplasia. The prostate gland enlarges during a man’s life via multiple growth spurts, with the last growth phase starting when a man is in his 50s. Problems with urinary flow usually appear only after the age of 50 as a consequence of the final growth phase. There is some evidence to suggest that the relative increase in circulating estrogen associated with aging may strengthen the effect of DHT on the prostate with promotion of cellular growth and glandular enlargement.


The pathophysiology of urinary symptoms associated with BPH can be attributed to both static and dynamic factors. The static component is a result of the enlargement of the prostate impinging upon the prostatic urethra and bladder outlet, whereas the dynamic component is related to the tension of prostatic smooth muscle. The static component may cause urinary symptoms because of excessive growth of the glandular tissue in the periurethral zone or stromal tissue in the transition zone. The direction of growth of glandular tissue can affect urinary flow. Growth toward the inside will probably cause direct urinary flow obstruction. The beginning phase of an outward growth of glandular tissue is less likely to cause urinary flow obstruction. The prostatic capsule may prevent progressive outward expansion of the prostate. Therefore, ongoing outward growth may ultimately result in compressive forces on the prostatic urethra. If the prostate can be thought of as a doughnut, then the hole in the middle of the doughnut becomes smaller by inward growth of tissue and/or inward compression when the capsule restricts outward expansion. Thus the size of the prostate as detected by a DRE, which correlates with outward growth, may not correlate with urinary flow symptoms. In addition, an increase in the tone of prostatic smooth muscle may lead to obstructive urinary symptoms without any prostate enlargement.


Voiding of urine is a synchronized action between the bladder and urethra. The bladder is innervated by parasympathetic nerves and their stimulation causes bladder muscle contraction leading to voiding of urine. Stimulation of sympathetic nerves that innervate the bladder neck and prostate causes closure of the bladder outlet. A voluntary sphincter in the bladder neck, supplied by the pudendal nerve and controlled by the higher cortical centers and diencephalons, enables conscious control of urine voiding. Multiple factors, including changes in the bladder, prostate, and/or urethra, can lead to voiding dysfunction in an aging male.



Lower urinary tract symptoms can occur from a variety of conditions within and outside of the urinary tract; a diagnostic evaluation is necessary to determine etiology.




Clinical manifestations


Historically, the terms prostatism and symptoms of benign prostatic hyperplasia have been used to describe lower urinary tract symptoms (LUTS) in men. Although the term prostatism implies a prostatic cause for urinary symptoms, frequently no evidence exists for such an implication. LUTS are very common both in elderly men and women. BPH is a precise histological term, yet many older men with LUTS are described as suffering from the symptoms of BPH or from clinical BPH without this level of diagnostic evaluation. The use of the specific histological term is confusing in routine clinical practice.


The preferred term, lower urinary tract symptoms (LUTS), describes patients’ complaints without implying their cause. This is important because the symptoms are not gender, age, or disease specific. Transient causes of LUTS include drugs, dietary factors, restricted mobility, constipation, infection, inflammation, polyuria, and psychological causes. Stimulation of the alpha-1 adrenergic receptors in the smooth muscle of the stroma and capsule of the prostate, as well as in the bladder neck, can cause an increase in smooth-muscle tone, which can worsen LUTS.


Diseases that originate from the lower urinary tract (prostatic and nonprostatic diseases) and diseases that do not originate from the lower urinary tract (such as those that can affect the neural control of voiding mechanisms—for example, diabetes mellitus, cerebrovascular accident, Parkinson’s disease, multiple sclerosis, and spinal cord injury) can affect the primary structures and systems involved with voiding and lead to LUTS.


Histologically, BPH is categorized as a hyperplastic process that results in enlargement of the prostate that may cause restriction in the flow of urine from the bladder. Subsequently obstruction induces bladder wall changes, such as thickening, increase in trabeculations, and irritability, that contribute to LUTS. Increased bladder sensitivity (detrusor overactivity [DO]) occurs even with small volumes of urine in the bladder. The bladder may gradually weaken and lose the ability to empty completely, leading to increased residual urine volume and, possibly, acute or chronic urinary retention.


The International Continence Society has published standard terminology to define symptoms, signs, urodynamic observations, and conditions associated with lower urinary tract dysfunction.1 LUTS are divided into three groups: storage, voiding, and postmicturition symptoms. Storage (irritative) symptoms include increased daytime frequency (voiding too often during the day), nocturia (to wake at night one or more times to void), urgency (sudden urge to urinate that is difficult to defer), incontinence (complaint of any involuntary leakage of urine), and bladder sensation (defined by five categories: normal, increased, reduced, absent, and nonspecific). Voiding (obstructive) symptoms are experienced during the voiding phase and include a slow stream (perception of reduced urine flow), splitting or spraying (character of stream), intermittent stream (urine flow that starts and stops), hesitancy (difficulty in initiating micturition), straining (muscular effort used to initiate, maintain, or improve the urinary stream), and terminal dribble (prolonged final part of micturition, when flow has slowed to a trickle/dribble). Postmicturition symptoms are experienced immediately after micturition and include a feeling of incomplete emptying (sensation of not emptying the bladder completely after finishing urinating) and postmicturition dribble (involuntary loss of urine immediately after completion of urination, usually after leaving the toilet in men, or after rising from the toilet in women).



CASE 1   Paul Phillips (Part 2)


Mr. Phillips’s initial assessment reveals urinary frequency, urgency, nocturia, and straining with an IPSS (International Prostate Symptom Score) of 12. DRE reveals normal sphincter tone, prostate about 20 g with no asymmetry or nodules. Urinalysis is unremarkable. You educate Mr. Phillips about LUTS, discuss transient causes including caffeine and alcohol, and recommend discontinuation of NoDoz, avoidance of fluids 2 hours before bedtime, and dietary modifications with use of a bladder diary to help him identify triggers.


Two months later at a follow-up visit Mr. Phillips reports his frequency, urgency, and nocturia are much improved, with an IPSS of 5. He notes, “Now I can spend time with my friends and play a round of golf without worrying.”





Medications should always be considered in the differential diagnosis as a cause of LUTS or worsening BPH symptoms.




BPH: Differential diagnosis and assessment


The diagnosis of BPH in men is typically clinical, and one of exclusion. When a urinary symptom is noted, a standardized questionnaire, such as the IPSS, is used to quantify the severity of LUTS (Figure 51-1). The IPSS assesses seven symptoms during the past month. The questions address the following factors: feeling of incomplete bladder emptying, frequency, intermittency, urgency, weak stream, straining, and nocturia; each is rated on the scale on which 0 = none and 5 = almost always. The symptom categories are based on the summative score: 0 to 7 mild, 8 to 19 moderate, and 20 to 35 severe.



Other possible contributors are queried, such as endocrine (e.g., poorly controlled diabetes), neurologic (e.g., neurogenic bladder), symptoms of urinary tract infection, and previous urologic conditions (e.g., urethral stricture, bladder neck contracture, interstitial cystitis). Although nonspecific for BPH, DRE is performed to rule out other conditions. The prostate size, tenderness, and presence of nodules are noted. Because hyperplasia may only involve the transitional zone, the DRE can be unremarkable or it may reveal an enlarged, smooth, rubbery, symmetrical gland. Lower abdominal/suprapubic palpation may identify a distended bladder. Urinalysis is routinely performed to evaluate for urinary tract infection, hematuria, and glycosuria; BPH is associated with an unremarkable urinalysis.



Lifestyle modifications can be effective in reducing urinary symptoms, and bladder diaries often assist a person in making these changes.



Additional tests are considered optional and are based on clinical indications. If urinary retention is suspected, postvoid residual urine volume (often done by office or bedside bladder scan) is performed. Serum creatinine measurement may be used to assess kidney function and the possibility of obstructive uropathy and/or intrinsic renal disease. Pressure-flow urodynamic studies are commonly performed prior to surgical interventions. These tests can also be considered when the diagnosis is uncertain.



BPH: Management


The initiation of BPH therapy depends on the patient and is driven by the effect of the symptoms on the patient’s quality of life (Table 51-1 and Figure 51-2). All patients should be educated regarding lifestyle modification. Men with mild to moderate symptoms may be satisfied with lifestyle modification only. Both medical and surgical treatments are also available, with medication the usual first approach. Indications for surgical treatment include patient preference, dissatisfaction with medication, and refractory urinary retention. Complications from prostatic obstruction, including renal dysfunction, bladder stones, recurrent urinary tract infections, and hematuria are also managed surgically. The selection of surgical approach is dependent on patient anatomy and the surgeon’s experience as well as the potential benefits and risks for complications.





Lifestyle interventions and self-management


BPH is a chronic condition with symptoms that impact men’s quality of life. As with other chronic conditions, patients benefit from self-management interventions (SMIs) that empower the individual’s involvement and control of treatment. SMI helps patients learn what to do and develops their belief in their own ability to use knowledge and skills toward achieving realistic, desired outcomes. SMI has been shown to be effective in men with BPH LUTS as an alternative to initial pharmacologic management and as adjuvant therapy for men who are using alpha-blockers.2,3 Three major categories for LUTS SMI are (1) education and reassurance, (2) lifestyle modification, and (3) behavioral interventions.


Education and reassurance provides knowledge about male anatomy and the relationship of the bladder and enlarged prostate to voiding symptoms. Patients are reassured that LUTS commonly occur in the absence of cancer. Illustrations and written information facilitate understanding and retention of information. Group settings can also be used for providing education and sharing effective strategies.


Lifestyle modifications

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Jun 8, 2016 | Posted by in GERIATRICS | Comments Off on Benign prostate disease

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