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Benign Prostatic Hyperplasia (BPH)

(Benign Prostatic Hypertrophy)

By

Gerald L. Andriole

, MD, Washington University School of Medicine

Last full review/revision Nov 2020| Content last modified Nov 2020
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Benign prostatic hyperplasia (BPH) is nonmalignant adenomatous overgrowth of the periurethral prostate gland. Symptoms are those of bladder outlet obstruction—weak stream, hesitancy, urinary frequency, urgency, nocturia, incomplete emptying, terminal dribbling, overflow or urge incontinence, and complete urinary retention. Diagnosis is based primarily on digital rectal examination and symptoms; cystoscopy, transrectal ultrasonography, urodynamics, or other imaging studies may also be needed. Treatment options include 5 alpha-reductase inhibitors, alpha-blockers, tadalafil, and surgery.

Using the criteria of a prostate volume > 30 mL and a moderate or high American Urological Association Symptom Score (see table American Urological Association Symptom Score for Benign Prostatic Hyperplasia ), the prevalence of BPH in men aged 55 to 74 without prostate cancer is 19%. But if voiding criteria of a maximal urinary flow rate < 10 mL/sec and a postvoid residual urine volume > 50 mL are included, the prevalence is only 4%. Based on autopsy studies, the prevalence of BPH increases from 8% in men aged 31 to 40 years to 40 to 50% in men aged 51 to 60 years and to > 80% in men > 80 years.

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The etiology is unknown but probably involves hormonal changes associated with aging.

Pathophysiology of BPH

Multiple fibroadenomatous nodules develop in the periurethral region of the prostate, probably originating within the periurethral glands rather than in the true fibromuscular prostate (surgical capsule), which is displaced peripherally by progressive growth of the nodules.

Symptoms and Signs of BPH

Lower urinary tract symptoms

Symptoms of benign prostatic hyperplasia (BPH) include a constellation of symptoms that are often progressive, known collectively as lower urinary tract symptoms (LUTS):

  • Urinary frequency

  • Urgency

  • Nocturia

  • Hesitancy

  • Intermittency

Frequency Urinary Frequency Urinary frequency is the need to urinate many times during the day, at night (nocturia), or both but in normal or less-than-normal volumes. Frequency may be accompanied by a sensation of an... read more , urgency, and nocturia are due to incomplete emptying and rapid refilling of the bladder. Decreased size and force of the urinary stream cause hesitancy and intermittency.

Pain and dysuria are usually not present. Sensations of incomplete emptying, terminal dribbling, overflow incontinence Types Urinary incontinence is involuntary loss of urine; some experts consider it present only when a patient thinks it is a problem. The disorder is greatly underrecognized and underreported. Many... read more , or complete urinary retention Urinary Retention Urinary retention is incomplete emptying of the bladder or cessation of urination. Urinary retention may be Acute Chronic Causes include impaired bladder contractility, bladder outlet obstruction... read more may ensue. Straining to void can cause congestion of superficial veins of the prostatic urethra and trigone, which may rupture and cause hematuria. Straining also may acutely cause vasovagal syncope and, over the long term, may cause dilation of hemorrhoidal veins or inguinal hernias.

Urinary retention

Some patients present with sudden, complete urinary retention, with marked abdominal discomfort and bladder distention. Retention may be precipitated by any of the following:

  • Prolonged attempts to postpone voiding

  • Immobilization

  • Exposure to cold

  • Use of anesthetics, anticholinergics, sympathomimetics, opioids, or alcohol

Symptom scores

Symptoms can be quantitated by scores, such as the 7-question American Urological Association Symptom Score (see table American Urological Association Symptom Score for Benign Prostatic Hyperplasia ). This score also allows doctors to monitor symptom progression:

  • Mild symptoms: Scores 1 to 7

  • Moderate symptoms: Scores 8 to 19

  • Severe symptoms: Scores 20 to 35

Digital rectal examination

On digital rectal examination, the prostate usually is enlarged and nontender, has a rubbery consistency, and in many cases has lost the median furrow. However, prostate size as detected with digital rectal examination may be misleading; an apparently small prostate may cause obstruction. If distended, the urinary bladder may be palpable or percussible during abdominal examination. Firm or hard areas in the prostate may indicate prostate cancer Prostate Cancer Prostate cancer is usually adenocarcinoma. Symptoms are typically absent until tumor growth causes hematuria and/or obstruction with pain. Diagnosis is suggested by digital rectal examination... read more .

Diagnosis of BPH

  • Digital rectal examination

  • Urinalysis and urine culture

  • Prostate-specific antigen level

  • Sometimes uroflowmetry and bladder ultrasonography

The lower urinary tract symptoms of benign prostatic hyperplasia (BPH) can also be caused by other disorders, including infection Introduction to Urinary Tract Infections (UTIs) Urinary tract infections (UTIs) can be divided into upper tract infections, which involve the kidneys (pyelonephritis), and lower tract infections, which involve the bladder (cystitis), urethra... read more , prostate cancer Prostate Cancer Prostate cancer is usually adenocarcinoma. Symptoms are typically absent until tumor growth causes hematuria and/or obstruction with pain. Diagnosis is suggested by digital rectal examination... read more , and overactive bladder Urinary Incontinence in Adults Urinary incontinence is involuntary loss of urine; some experts consider it present only when a patient thinks it is a problem. The disorder is greatly underrecognized and underreported. Many... read more . Furthermore, BPH and prostate cancer may coexist. Although palpable prostate tenderness suggests infection, digital rectal examination findings in BPH and cancer often overlap. Although cancer may cause a stony, hard, nodular, irregularly enlarged prostate, most patients with cancer, BPH, or both have a benign-feeling, enlarged prostate. Thus, testing should be considered for patients with symptoms or palpable prostatic abnormalities.

Typically, urinalysis and urine culture are done, and serum prostate-specific antigen (PSA) levels are measured. Men with moderate or severe symptoms of obstruction may also have uroflowmetry (an objective test of urine volume and flow rate) with measurement of postvoid residual volume by bladder ultrasonography. Flow rate < 15 mL/sec suggests obstruction, and postvoid residual volume > 100 mL suggests retention.

Prostate-specific antigen (PSA) levels

Interpreting prostate-specific antigen (PSA) levels can be complex. The PSA level is moderately elevated in 30 to 50% of patients with BPH, depending on prostate size and degree of obstruction, and is elevated in 25 to 92% of patients with prostate cancer, depending on the tumor volume.

In patients without cancer, serum PSA levels > 1.5 ng/mL (1.5 mcg/L) usually indicate a prostate volume 30 mL. If the PSA level is > 4 ng/mL (4 mcg/L), further discussion/shared decision-making regarding other tests or biopsy is recommended.

For men < 50 or those at high risk of prostate cancer, a lower cutoff (PSA > 2.5 ng/mL [2.5 mcg/L]) may be used. Other measures, including rate of PSA increase, free-to-bound PSA ratio, and other markers, may be useful. (A full discussion of prostate cancer screening and diagnosis Diagnosis Prostate cancer is usually adenocarcinoma. Symptoms are typically absent until tumor growth causes hematuria and/or obstruction with pain. Diagnosis is suggested by digital rectal examination... read more can be found elsewhere in THE MANUAL.)

Other testing

Transrectal biopsy is usually done with ultrasound guidance and is usually only indicated if there is suspicion of prostate cancer. Transrectal ultrasonography is an accurate way to measure prostate volume.

Clinical judgment must be used to evaluate the need for further testing. Contrast imaging studies (eg, CT, intravenous urography [IVU]) are rarely necessary unless the patient has had a urinary tract infection (UTI) with fever or obstructive symptoms have been severe and prolonged. Upper urinary tract abnormalities that usually result from bladder outlet obstruction include upward displacement of the terminal portions of the ureters (fish hooking), ureteral dilation, and hydronephrosis. If an upper tract imaging study is warranted due to pain or elevated serum creatinine level, ultrasonography may be preferred because it avoids radiation and IV contrast exposure.

Alternatively, men whose PSA levels warrant testing can undergo multiparametric MRI, which is more sensitive (although less specific) than transrectal biopsy. Restricting biopsies to areas found to be suspect on multiparametric MRI may reduce the number of prostate biopsies and diagnoses of clinically insignificant prostate cancers, as well as possibly increasing diagnoses of clinically significant prostate cancers (1 Diagnosis reference Benign prostatic hyperplasia (BPH) is nonmalignant adenomatous overgrowth of the periurethral prostate gland. Symptoms are those of bladder outlet obstruction—weak stream, hesitancy, urinary... read more ).

Cystoscopy may help determine the optimal surgical approach and to rule out other obstructive causes such as strictures.

Diagnosis reference

  • 1. Ahmed HU, El-Shater Bosaily A, Brown LC, et al: Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): A paired validating confirmatory study. Lancet 389(10071):815-822, 2017. doi: 10.1016/S0140-6736(16)32401-1

Treatment of BPH

Urinary retention

Significant urinary retention requires immediate decompression. Passage of a standard urinary catheter is first attempted; if a standard catheter cannot be passed, a catheter Bladder Catheterization Bladder catheterization is used to do the following: Obtain urine for examination Measure residual urine volume Relieve urinary retention or incontinence Deliver radiopaque contrast agents or... read more with a coudé tip may be effective. If this catheter cannot be passed, flexible cystoscopy or insertion of filiforms and followers (guides and dilators that progressively open the urinary passage) may be necessary. (This procedure should usually be done by a urologist.) Suprapubic percutaneous decompression of the bladder may be used if transurethral approaches are unsuccessful.

Drug therapy

For partial obstruction with troublesome symptoms, all anticholinergics and sympathomimetics (many available in over-the-counter [OTC] preparations), and opioids should be stopped, and any infection should be treated with antibiotics.

For patients with mild to moderate obstructive symptoms, alpha-adrenergic blockers (eg, terazosin, doxazosin, tamsulosin, alfuzosin) may decrease voiding problems. The 5 alpha-reductase inhibitors (finasteride, dutasteride) may reduce prostate size, decreasing voiding problems over months, especially in patients with larger (> 30 mL) glands. A combination of both classes of drugs is superior to monotherapy. For men with concomitant erectile dysfunction Erectile Dysfunction Erectile dysfunction is the inability to attain or sustain an erection satisfactory for sexual intercourse. Most erectile dysfunction is related to vascular, neurologic, psychologic, and hormonal... read more , daily tadalafil may help relieve both conditions. Many OTC complementary and alternative agents are promoted for treatment of BPH, but none, including the thoroughly studied saw palmetto Saw Palmetto Saw palmetto (Serenoa repens, Serenoa serrulata) berries contain the plant’s active ingredients. The active ingredients, thought to be fatty acids, seem to inhibit 5-alpha-reductase, thus opposing... read more , has been shown to be more efficacious than placebo.

Surgery

Surgery is done when patients do not respond to drug therapy or develop complications such as recurrent urinary tract infection Introduction to Urinary Tract Infections (UTIs) Urinary tract infections (UTIs) can be divided into upper tract infections, which involve the kidneys (pyelonephritis), and lower tract infections, which involve the bladder (cystitis), urethra... read more , urinary calculi Urinary Calculi Urinary calculi are solid particles in the urinary system. They may cause pain, nausea, vomiting, hematuria, and, possibly, chills and fever due to secondary infection. Diagnosis is based on... read more , severe bladder dysfunction, or upper tract dilation. Transurethral resection of the prostate (TURP) is the standard (1 Treatment reference Benign prostatic hyperplasia (BPH) is nonmalignant adenomatous overgrowth of the periurethral prostate gland. Symptoms are those of bladder outlet obstruction—weak stream, hesitancy, urinary... read more ). Erectile function and continence are usually retained, although about 5 to 10% of patients experience some postsurgical problems, most commonly retrograde ejaculation. The incidence of erectile dysfunction Erectile Dysfunction Erectile dysfunction is the inability to attain or sustain an erection satisfactory for sexual intercourse. Most erectile dysfunction is related to vascular, neurologic, psychologic, and hormonal... read more after TURP is between 1 and 35%, and the incidence of incontinence Urinary Incontinence in Adults Urinary incontinence is involuntary loss of urine; some experts consider it present only when a patient thinks it is a problem. The disorder is greatly underrecognized and underreported. Many... read more is about 1 to 3%. However, technical advances such as the use of a bipolar resectoscope, which allows use of saline irrigation, have greatly improved the safety of TURP by averting hemolysis and hyponatremia.

About 10% of men undergoing TURP need the procedure repeated within 10 years because the prostate continues to grow. Various laser ablation techniques are being used as alternatives to TURP. Larger prostates (usually > 75 grams) traditionally require open surgery via a suprapubic or retropubic approach, although some newer techniques such as the holmium laser enucleation of the prostate (HoLEP) can be done transurethrally. All surgical methods require postoperative catheter drainage for 1 to 7 days.

Other procedures

Alternatives to TURP include microwave thermotherapy, electrovaporization, various laser techniques, high-intensity focused ultrasonography, transurethral needle ablation, radiofrequency vaporization, pressurized heated water injection therapy, urethral lift, steam injection therapy, and intraurethral stents. The circumstances under which these procedures should be used have not been firmly established, but those done in the physician’s office (microwave thermotherapy and radiofrequency procedures) are being more commonly used and do not require use of general or regional anesthesia. Their long-term ability to alter the natural history of BPH is under study.

Treatment reference

  • 1. Parsons JK, Barry MJ, Dahm P, et al: Benign prostatic hyperplasia: Surgical management of benign prostatic hyperplasia/lower urinary tract symptoms (2018, amended 2019, 2020). American Urological Association.

Key Points

  • Benign prostatic hyperplasia (BPH) is extremely common with aging but only sometimes causes symptoms.

  • Acute urinary retention can develop with exposure to cold, prolonged attempts to postpone voiding, immobilization, or use of anesthetics, anticholinergics, sympathomimetics, opioids, or alcohol.

  • Evaluate patients with a digital rectal examination and usually urinalysis, urine culture, and PSA.

  • In men with BPH, avoid use of anticholinergics, sympathomimetics, and opioids.

  • Consider relieving troublesome obstructive symptoms with alpha-adrenergic blockers (eg, terazosin, doxazosin, tamsulosin, alfuzosin), 5 alpha-reductase inhibitors (finasteride, dutasteride), or tadalafil, especially if there is concomitant erectile dysfunction.

  • Consider TURP or other ablation technique if BPH causes complications (eg, recurrent calculi, bladder dysfunction, upper tract dilation) or if bothersome symptoms are drug resistant.

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