Atlas of pathophysiology, 2 Edition

Part II - Disorders

Genital Diseases

Benign Prostatic Hyperplasia

In benign prostatic hyperplasia (BPH), also known as benign prostatic hypertrophy, the prostate gland enlarges enough to compress the urethra and cause overt urinary obstruction. Depending on the size of the enlarged prostate, the age and health of the patient, and the extent of obstruction, BPH is treated symptomatically or surgically.

Age Alert

BPH is common, affecting more than 90% of men over age 80.

Causes

·   Age-associated changes in hormone activity

·   Arteriosclerosis

·   Inflammation

·   Metabolic or nutritional disturbances

Pathophysiology

Androgenic hormone production decreases with age, causing imbalance in androgen and estrogen levels and high levels of dihydrotestosterone, the main prostatic intracellular androgen. The shift in hormone balance induces the early, nonmalignant changes of BPH in periurethral glandular tissue. The growth of the fibroadenomatous nodules (masses of fibrous glandular tissue) progresses to compress the remaining normal gland (nodular hyperplasia). The hyperplastic tissue is mostly glandular, with some fibrous stroma and smooth muscle. As the prostate enlarges, it may extend into the bladder and obstruct urinary outflow by compressing or distorting the prostatic urethra. Progressive bladder distention may lead to formation of a pouch that retains urine when the rest of the bladder empties. This retained urine may lead to calculus formation or cystitis.

Signs and symptoms

Presenting signs and symptoms

·   Reduced urinary stream caliber and force

·   Urinary hesitancy

·   Feeling of incomplete voiding, interrupted stream

As obstruction increases

·   Frequent urination with nocturia

·   Sense of urgency

·   Retention, dribbling, incontinence

·   Possible hematuria

·   Urinary tract infection (UTI)

Diagnostic test results

·   Excretory urography rules out urinary tract obstruction, hydronephrosis (distention of the renal pelvis and calices due to obstruction of the ureter and consequent retention of urine), calculi or tumors, and filling and emptying defects in the bladder.

·   Cystoscopy rules out other causes of urinary tract obstruction (neoplasm, calculi).

·   Elevated blood urea nitrogen and serum creatinine levels (suggest renal dysfunction).

·   Laboratory studies reveal elevated prostate-specific antigen; however, prostatic carcinoma must be ruled out.

·   Urinalysis and urine cultures show hematuria, pyuria, and, with bacterial count more than 100,000/l, revealing UTI.

·   Cystourethroscopy for severe symptoms (definitive diagnosis) shows prostate enlargement, bladder-wall changes, and a raised bladder. (Cystourethroscopy is only done immediately before surgery to determine the next course of therapy.)

Treatment

Conservative therapy

·   Prostate massages

·   Sitz baths

·   Fluid restriction for bladder distention

·   Antimicrobials for infection

·   Regular ejaculation

·   Alpha-adrenergic blockers (terazosin, prazosin)

·   Medical management to reduce risk of urinary retention (finasteride)

·   Continuous drainage with a urinary catheter to alleviate urine retention (high-risk patients)

Surgical procedures (to relieve intolerable symptoms)

·   Suprapubic (transvesical) resection

·   Transurethral resection

·   Retropubic (extravesical) resection allowing direct visualization; usually maintains potency and continence

·   Suprapubic cystostomy under local anesthetic if indwelling urinary catheter can't be passed transurethrally

·   Laser excision to relieve prostatic enlargement

·   Nerve-sparing surgery to reduce common complications

·   Indwelling urinary catheter for urine retention

·   Balloon dilation of urethra and prostatic stents to maintain urethral patency

P.303

PROSTATIC ENLARGEMENT

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Clinical Tip: Palpating The Prostate Gland

To detect early signs of prostatic enlargement follow these steps:

·   Have patient stand and lean over the examination table; if he can't do this, have him lie on his left side with his right knee and hip flexed or with both knees drawn to his chest.

·   Inspect the skin of the perineal, anal, and posterior scrotal walls.

·   Insert lubricated gloved finger into the rectum.

·   Palpate the prostate through the anterior rectal wall.

·   The gland should feel smooth and rubbery, about the size of a walnut.

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