Recent Update In Benign Prostatic Hyperplasia

Ahmad Kasraeian, M.D. is Chief, Division of Urology at
Baptist Medical Center Beaches and Methodist Medical Center.

Introduction

Benign Prostatic Hyperplasia (B.P.H.) is the most common benign tumor in men, and is the most frequent cause of symptoms of urinary obstruction in men over 50 years of age. The prevalence of B.P.H. increases with age. As the life expectancy is increasing, primary physicians are likely to see more patients with B.P.H. in coming years.

The pathogenesis of B.P.H. is not completely understood. Many clinical and experimental studies support the role of androgens in genesis of B.P.H. For centuries it has been known that castration in older men results in clinical improvement of the obstructive symptoms and a decrease in prostate size. Earlier, testosterone was thought to be the primary cause of B.P.H. However since the discovery of five alpha reductase deficiency syndrome, it is recognized that dihydrotestosterone, and not testosterone, is the hormone responsible for the development of B.P.H. in men. Five alpha reductase is necessary for conversion of testosterone to dihydroxytestosterone. Studies of race, religion, nationality, diet, body habits and other factors in the potential genesis of B.P.H. have shown inconclusive results.

Clinical Manifestation

Benign Prostatic Hyperplasia develops in the transitional zone and periurethral area, as both glandular and stromal hyperplasia, with different ratios of stroma to glands in different patients. At the beginning, increased bladder outlet resistance is compensated by bladder muscular hypertrophy and the patient will usually have minimal symptoms. However, with the progression of obstruction, symptoms appear. Symptoms associated with B.P.H. can be obstructive, i.e., hesitancy, straining, weak stream, terminal dribbling, prolonged voiding, urinary retention and overflow incontinence. In addition, with the development of bladder instability, frequency, nocturia, urgency, urgency incontinence and small voided volume occur. Hematuria may also be associated with B.P.H., and is usually present at the beginning of urination (initial hematuria). Hematuria is more commonly associated with B.P.H. than with carcinoma of the prostate. (Table 1)

Table 1.

Obstructive Symptoms

Hesitancy
Straining
Weak stream
Narrow stream
Terminal dribbling
Prolonged voiding
Overflow incontinence
Suprapubic pressure / pain
Initial hematuria

Irritative Symptoms

Frequency
Nocturia
Urgency
Urgency incontinence
Small voided urine volume

As the severity of vesicle neck and prostatic urethral obstruction increases, patients may become unable to completely empty the bladder. Associated with a gradual increase in residual urine, the incidence of urinary tract infection increases. Eventually, a patient will develop urinary retention and overflow incontinence if B.P.H. is left untreated. Renal failure and hydronephrosis can develop in patients with prolonged severe obstruction. Acute urinary retention is frequently precipitated by urinary tract infection, prostatic infarction, ingestion of alcohol, anticholegenics, anti-depressants, tranquilizers or decongestants.

Patient Evaluation

To assist physicians in evaluating a patient's symptoms, multiple symptom questionnaires have been developed. These include the Madsen-Inversen point system, the Bayarsky Guideline, the Main Medical Assessment Program and the American Urological Associated (AUA) symptom index. The latter has been used increasingly in the United States (Table 2). This one page symptom scoring system questionnaire is designed to be completed by the patient and is used to assess and quantify urinary complaints. A score of 0-7 is considered mild, 8-19 moderate, and over 20 is severe.

B.P.H. is the most common cause of irritative and/or obstructive voiding symptoms in men. To exclude other conditions that may stimulate B.P.H., the patient should be carefully questioned and examined for the presence or absence of cystitis, prostatitis, bladder and prostate cancer. Past history of urological procedures, urethritis, neurological conditions and drug ingestion is also important (Table 3).

In the physical examination, the patient should be checked for costovertebral angle tenderness, suprapubic tenderness and a suprapubic mass. A 360 degree digital examination should be carried out. The prostate is palpated with attention to size, consistency, shape, presence of nodularity and tenderness. The size of the prostate in digital examination does not always correlate with the patient's symptoms. Patients with a small prostate and a large median lobe hypertrophy may experience marked obstructive symptoms, whereas, patients with marked prostate enlargement may have minimal or no urinary obstructive symptoms. Evaluation of external sphincter tone during rectal exams can reflect the status of vesicle innervation.

Patients with moderate to severe symptom scoring need to have a few laboratory tests such as a urinalysis, urine culture, serum creatinine and prostate specific antigen. Urine cytology is necessary in the evaluation of patients with hematuria. Urodynamic studies include uroflowmetry, cystometry and pressure flow studies. These studies may provide information in the evaluation of the severity of bladder outlet obstruction and to rule out a neurological disorder of the bladder muscle. The intravenous urogram is not a necessary part of the evaluation and rarely influences the choice of treatment, but may be useful in assessing the presence or absence of hydronephrosis, renal or bladder calculi, hydro-ureter and genitourinary malignancies. Cysto-urethroscopy helps to determine the size of the prostate, the length of the prostatic urethra and status of vesicle neck and the presence or absence of urethral stricture. It is also use to evaluate the severity of bladder trabeculation and detecting other bladder conditions, including diverticula, stones and cancer.

Treatment of Benign Prostatic Hypertrophy

Prior to this decade, surgery was the only option available for treatment of B.P.H. More than two decades ago Cain et al. reported on the potential significance of alpha adrenergic drug in the treatment of B.P.H. Medical management of B.P.H. with alpha adrenergic drugs did not gain popularity until the introduction of long acting alpha adrenergic blocker, which was originally developed for treatment of hypertension. Alpha adrenergic blockers cause relaxation of smooth muscle in the prostate and bladder neck, thereby improving the dynamic component of the obstruction.

To initiate proper treatment in patients with B.P.H., it is important to start with a complete history and a physical exam to rule out other possibilities for the patient's urinary symptoms and obtain an AUA scoring. Usually, with mild symptoms (0-7 AUA symptoms index score), the patient will be advised watchful waiting with reassurance and follow-up. For patients with moderate symptoms (8-19 AUA score), medical management may include alpha adrenergic blockers or 5 alpha reductase inhibitors. Less frequently, leuteinizing hormone releasing hormone agonists, progestational agents, or anti-androgens may be utilized.

Alpha adrenergic blockers include Terazosin, Alfuzosin, Prezesin, Dexazosin, Tamsulosin and Amsulosin. The most commonly used alpha adrenergic blockers in the United States are Terazosin and Dexazosin. These exhibit maximum response in 3-6 weeks. The side effects include asthnia, dizziness, postural hypotension, general malaise, headache and syncope. Recently, Tamsulosin Hydrochloride has been introduced, which has 7-38 fold more affinity for alpha 1A adrenoceptor than alpha 1B. This agent has a minimal effect on patients blood pressure, eliminates the need for dose titration, and is associated with more rapid symptomatic improvement.

Five alpha reductase inhibitors include Finasteride, the only drug in this class extensively studied in the treatment of B.P.H. It is most effective in patients with prostates over 40gm. To achieve the maximum therapeutic response, the treatment must be continued for 4-6 months. Common side effects of Finasteride include decreased libido, ejaculatory dysfunction or erectile dysfunction. Finasteride usually decreases the P.S.A. level by 40% to 50% during the course of treatment.

Usually, patients with severe symptoms (AUA score 20-35) may be initially treated medically utilizing maximum dosage. If the patient shows no improvement, then alternative and more invasive treatment options should be considered. Transurethral resection of the prostate (TURP), with some recent modifications, is still the most common surgical treatment of B.P.H. Different types of treatment of B.P.H. can be selected by a urologist during cystoscopic evaluation of a patient.

When surgery is performed, patients with smaller prostates (less than 60-80 gms) are generally treated by transurethral procedures. Transuretheral resection of the prostrate is the most frequently used procedure. Other options less frequently used are transurethral electrovaporization of the prostate, transurethral needle ablation of the prostrate, transurethral incision of the prostate, microwave hyperthermia, microwave thermal therapy, indwelling metallic stent or urolume endoprosthesis, laser prostatectomy and high intensity focused ultrasound treatment of prostate. Common complications of TURP include immediate post-op hyponatremia, urinary incontinence, stricture, urinary tract infection, need for blood transfusion, and sexual dysfunction.

Open prostatectomy (retropubic prostatectomy and suprapubic prostatectomy) usually is performed in patients with prostates over 60 to 80 grams and in patients with other conditions such as large bladder diverticula or large bladder stone. Absolute indications for surgery include azotemia, hydronephrosis, bladder decompensation with urinary retention, overflow incontinence and severe recurrent hematuria. Relative indications for surgery include acute urinary retention (17 to 60% of patients may be able to urinate when the catheter is discontinued), recurrent urinary tract infection, large residual urine volume, bladder instability and patient desire for surgical intervention.

Summary

In summary, over 50% of men over the age of 60 suffer from Benign Prostatic Hyperplasia. Annually, over 400,000 surgeries are performed to correct this problem. With the increase in life expectancy and the introduction of medical treatment in recent years, more primary care physicians will be involved in the initial treatment of B.P.H. I have emphasized the importance of careful evaluation of patients for the presence of other medical or associated conditions and the treatment options available for patients with mild, moderate, and severe AUA symptom index scores. Although a trial of medical therapy may frequently lead to improvement, surgery remains the most effective form of therapy in many cases.

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