Benign Prostatic Hyperplasia (Enlarged Prostate)

BENIGN PROSTATIC HYPERPLASIA (ENLARGED PROSTATE)

In many patients older than 50 years, the prostate gland enlarges, extending upward into the bladder and obstructing the outflow of urine by encroaching on the vesical orifice. This condition is known as benign prostatic hyperplasia (BPH), the enlargement, or hypertrophy, of the prostate. BPH is one of the most common pathologic conditions in older men (McConnell, 1998).

Clinical Manifestations

Examination reveals a prostate gland that is large, rubbery, and nontender. The cause is uncertain, but evidence suggests that hormones initiate hyperplasia of the supporting stromal tissue and the glandular elements in the prostate (McConnell, 1998). The hypertrophied lobes may obstruct the vesical neck or pros-tatic urethra, causing incomplete emptying of the bladder and urinary retention. As a result, a gradual dilation of the ureters (hydroureter) and kidneys (hydronephrosis) can occur. Urinary tract infections may result from urinary stasis, because some urine remains in the urinary tract and serves as a medium for infective organisms.

Assessment and Diagnostic Findings

The obstructive and irritative symptom complex (referred to as prostatism) includes increased frequency of urination, nocturia,urgency, hesitancy in starting urination, abdominal straining with urination, a decrease in the volume and force of the urinary stream, interruption of the urinary stream, dribbling (urine drib-bles out after urination), a sensation that the bladder has not been completely emptied, acute urinary retention (when more than 60 mL of urine remains in the bladder after urination), and re-current urinary tract infections. Ultimately, azotemia (accumula-tion of nitrogenous waste products) and renal failure can occur with chronic urinary retention and large residual volumes. Gen-eralized symptoms may also be noted, including fatigue, anorexia, nausea, vomiting, and epigastric discomfort. Other disorders pro-ducing similar symptoms include urethral stricture, prostate can-cer, neurogenic bladder, and urinary bladder stones.

A physical examination with DRE and diagnostic studies may be performed to determine the degree to which the prostate is en-larged, the presence of any changes in the bladder wall, and the efficiency of renal function. These tests may include urinalysis and urodynamic studies to assess urine flow. Renal function tests, including serum creatinine levels, may be performed to determine if there is renal impairment from prostatic back-pressure and to evaluate renal reserve. Complete blood studies are performed. Be-cause hemorrhage is a major complication of prostate surgery, all clotting defects must be corrected. A high percentage of patients with BPH have cardiac or respiratory complications, or both, because of their age; therefore, cardiac and respiratory function is also assessed.

Medical Management

The treatment plan depends on the cause of BPH, the severity of the obstruction, and the patient’s condition. If the patient is admitted on an emergency basis because he cannot void, he is immediately catheterized. The ordinary catheter may be too soft and pliable to advance through the urethra into the bladder. In such cases, a thin wire called a stylet is introduced (by a urologist) into the catheter to prevent the catheter from collapsing when it encounters resistance. In severe cases, metal catheters with a pro-nounced prostatic curve may be used. Sometimes an incision is made into the bladder (a suprapubic cystostomy) to provide drainage.

Although prostatectomy to re-move the hyperplastic prostatic tissue is frequently performed, other treatment options are available. These include “watchful waiting,” transurethral incision of the prostate (TUIP), balloon di-lation, alpha-blockers, 5-alpha-reductase inhibitors, transurethral laser resection, transurethral needle ablation, and microwave ther-motherapy (Lepor, 1998; Mebust, 1998; McCullough, 1998). Watchful waiting is the appropriate treatment for many patients because the likelihood of progression of the disease or the devel-opment of complications is unknown. Patients are monitored pe-riodically for severity of symptoms, physical findings, laboratory tests, and diagnostic urologic tests.

Alpha-adrenergic receptor blockers (eg, terazosin [Hytrin]) relax the smooth muscle of the bladder neck and prostate. These agents help to reduce obstructive symptoms in many patients.

Because the hormonal component of BPH has been identi-fied, one method of treatment involves hormonal manipulation with antiandrogen agents, such as finasteride (Proscar). In clini-cal studies, 5-alpha-reductase inhibitors such as finasteride have been effective in preventing the conversion of testosterone to di-hydrotestosterone (DHT). With decreased levels of DHT, sup-pression of glandular cell activity and decreases in prostate size have been demonstrated. Side effects of these medications in-clude gynecomastia (breast enlargement), erectile dysfunction, and flushing.

With ultrasound guidance, resection of the prostate can be ac-complished with lasers. The treated tissue either vaporizes or be-comes necrotic and sloughs. This treatment is delivered in the outpatient setting and generally results in less postoperative bleeding than a traditional surgical prostatectomy.

Transurethral needle ablation uses low-level radiofrequencies to produce localized heat to destroy prostate tissue while sparing the urethra, nerves, muscles, and membranes. The radiofrequen-cies are delivered by thin needles placed into the prostate gland from a catheter. The body then resorbs the dead tissue.

In microwave thermotherapy, heat is applied to the hypertro-phied prostatic tissue. A transurethral probe is inserted into the urethra, and microwaves are carefully directed to the prostate tis-sue. A water-cooling system helps to minimize damage to the ure-thra and decreases the discomfort from the procedure. The tissue becomes necrotic and sloughs.

Saw palmetto is a botanical remedy used for symptoms of mild to moderate BPH such as urinary frequency and decreased force of urine stream (Gerber, 2000; Marks, Partin, Epstein et al., 2000; Wilt, Ishani, Stark et al., 1998). It is theorized that saw palmetto works by interfering with the conversion of testosterone to DHT. In addition, saw palmetto may directly block the ability of DHT to stimulate prostate cell growth. It should not be used with finasteride or medications containing estrogen.