Porth's Essentials of Pathophysiology, 4e

1009

Disorders of the Male Genitourinary System

C h a p t e r 3 9

collecting system of the kidneys promotes hydroureter, hydronephrosis, and danger of eventual renal failure. Current practice suggests that the single most impor- tant factor in the evaluation and treatment of BPH is the man’s own experiences related to the disorder. The American Urological Association Symptom Index con- sists of seven questions about symptoms regarding incomplete emptying, frequency, intermittency, urgency, weak stream, straining, and nocturia. 46 The diagnosis of BPH is based on history, physical examination, digital rectal examination, urinalysis, blood tests for serum creatinine and prostate-specific antigen (PSA), and urine flow rate. The digital rectal examina- tion is used to examine the external surface and size of the prostate. An enlarged prostate found during a digital rectal examination does not always correlate with the degree of urinary obstruction. Some men can have greatly enlarged prostate glands with no urinary obstruction, but others may have severe symptoms without a palpable enlargement of the prostate. Urinalysis is done to detect bacteria, white blood cells, or microscopic hematuria in the presence of infection and inflammation. The serum creatinine test is used as an estimate of the glomerular filtration rate and renal function. The PSA test is used to screen for prostate cancer. These evaluation measures, along with the symptom index, are used to describe the extent of obstruction, determine if other diagnostic tests are needed, and establish the need for treatment. Treatment of BPH is determined by the degree of symptoms that the condition produces and complica- tions due to obstruction. When a man develops mild symptoms related to BPH, a “watchful waiting” stance often is taken. 44–46 The condition does not always run a predictable course; it may remain stable or even improve. Until the 1980s, surgery was the mainstay of treatment to alleviate urinary obstruction due to BPH. Currently, there is an emphasis on less invasive methods of treat- ment, including use of pharmacologic agents. However, when more severe signs of obstruction develop, surgi- cal treatment is indicated to provide comfort and avoid serious kidney damage. Pharmacologic management includes the use of 5 α -reductase inhibitors, α 1 -adrenergic blocking drugs, or a combination of the two drugs. 44,45 The 5 α -reductase inhibitors suchasfinasteride reduceprostate sizebyblock- ing the effect of androgens on the prostate. Finasteride causes atrophy of the prostate glandular epithelial cells, which results in a 20% to 30% reduction in volume. The onset is slow (3 to 6 months), but long-lasting. The presence of α -adrenergic receptors in prostatic smooth muscle has prompted the use of α 1 -adrenergic blocking drugs (e.g., prazosin, terazosin) to relieve pros- tatic obstruction and increase urine flow. Herbal therapies have been used for many years by men for the treatment of BPH and lower urinary tract symptoms. 44–46 Several studies have looked at the effects of these agents, including the extract of the saw pal- metto berry. Improvements in peak urine flow rates and nocturia can occur compared with placebo, but the durability of these effects is unproven. The long-term toxicity and mechanism of action of these agents remain

Anterior

Prostatic urethra

Posterior

NORMAL PROSTATE

Surgical capsule

NODULAR PROSTATIC HYPERPLASIA

CARCINOMA OF PROSTATE

distention, overflow incontinence may occur with the slightest increase in intra-abdominal pressure. The resulting obstruction to urinary flow can give rise to uri- nary tract infection, destructive changes of the bladder wall, hydroureter, and hydronephrosis. Hypertrophy and changes in bladder wall structure develop in stages. Initially, the hypertrophied fibers form trabeculations and then herniations, or sacculations; finally, diverticula develop as the herniations extend through the bladder wall (see Chapter 27, Fig. 27-4). Because urine seldom is completely emptied from them, these diverticula are readily infected. Back-pressure on the ureters and hyperplasia, which involves predominantly the periurethral part of the gland, the nodules compress and distort the urethra.The expansion of the central prostatic glands leads to compression of the peripheral parts and fibrosis, resulting in the formation of the so-called surgical capsule. Prostatic cancer usually arises from the peripheral glands and compression of the urethra is a late clinical event. (From Damjanov I, McCue PA.The lower urinary tract and male reproductive system. In: Rubin R, Strayer DS, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine. 6th ed. Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams &Wilkins; 2012:840.) FIGURE 39-12. Normal prostate, nodular benign prostatic hyperplasia, and cancer of the prostate. In prostatic