- Clinical science
Benign prostatic hyperplasia (BPH) is a non-neoplastic glandular and stromal hyperplasia of the transition zone of the prostate. It is a common disorder affecting ∼ 40% of the male population by the age of 50 years. Although the etiology has not been conclusively established, sex hormones (androgens, estrogens, and androgen-estrogen imbalance) have been implicated as a key factor in the development of prostatic hyperplasia. Patients present with symptoms of bladder irritation (urinary frequency, urgency, urge incontinence), bladder outlet obstruction (urinary hesitancy, straining to urinate, sensation of incomplete voiding), and/or hematuria. Digital rectal examination reveals a smoothly enlarged, non-tender, and firm prostate. Diagnosis can be confirmed on abdominal ultrasound which demonstrates an enlarged prostate and increased post-void residual urine in the bladder. Bladder outlet obstruction can be quantitatively measured on uroflowmetry which shows a decreased maximal urinary flow rate. BPH is graded as mild, moderate and severe based on the frequency and severity of the symptoms. Behavioral modifications (night-time fluid restriction, urinating in a sitting position, etc.) are advised in all patients who are managed conservatively. Patients with mild/moderate BPH respond well to medical management with alpha-blockers (tamsulosin, doxazosin), 5-alpha-reductase inhibitors (finasteride), and parasympatholytics (oxybutynin). Severe BPH, unsuccessful medical therapy, and complications due to BPH are indications for surgery (e.g., transurethral resection of prostate, TURP). Complications of BPH include recurrent urinary tract infections (UTIs), urinary retention, bladder calculi, hydroureteronephrosis, and chronic kidney disease. BPH can recur after TURP in ∼15% of men. Prostate cancer can occur in patients with BPH, including in those who have undergone TURP. Normal prostate specific antigen (PSA) screening protocol is followed in these patients.
- Benign prostatic syndrome : (BPS): caused by a benign hyperplasia of the transitional zone of the prostate
- Benign prostatic hyperplasia (BPH) : Benign glandular and stromal hyperplasia of the transitional zone of the prostate
- : (BOO): Any obstruction to urinary outflow from the bladder which presents as and is confirmed on urodynamic testing (see for causes of BOO)
- Age: Prevalence of BPH increases with age (∼ 70 % of males > 60 years).
- Race: BPH is equally prevalent in white, Asian, and black men. However, black men with BPH typically have more severe symptoms and greater total and transitional zone prostate volume.
Epidemiological data refers to the US, unless otherwise specified.
- The etiology is not fully understood
- The following factors play a role in prostatic hyperplasia and growth
- Androgens: Dihydrotestosterone (DHT) is a potent prostatic growth factor
- Gene amplification of androgen receptors: (present in the glandular epithelial cells and stromal cells) → increased androgen receptor sensitivity to androgens → prostatic hyperplasia
- Estrogens: Estrogens (mainly estradiol) are potent stimulators of prostatic hyperplasia.
- Androgen-estrogen imbalance: : As men age, testosterone levels decline, but estrogen levels remain the same → a higher estrogen/testosterone ratio.
- Stem cell proliferation and longevity: Abnormal proliferation and longer prostatic stem cell life-span
- Genetic susceptibility: Genes involved in the development of BPH include growth factor genes, androgen-regulator genes, apoptosis genes, and androgen-regulated genes.
- Hormonal factors
BPH is not a risk factor for the development of prostate cancer.
- The prostate consists of three distinct histologic zones
- The inner central zone
- The middle transition zone: BPH develops in this zone.
- The outer peripheral zone: Prostate cancer develops in this zone.
- A combination of etiological factors → glandular and stromal hyperplasia in the transition zone → prostatic urethral compression → bladder outlet obstruction → obstructive symptoms of BPH
- → detrusor overactivity (involuntary detrusor contractions during bladder filling) → irritative symptoms of BPH
- → weakening of the bladder wall → incomplete voiding → urinary stasis → predisposition to urinary tract infections, acute/chronic urinary retention, and formation of bladder stones
- → increased intracystic pressure while voiding → detrusor muscle hypertrophy → bladder trabeculation and pseudodiverticula formation
- Lower urinary tract symptoms (LUTS)
- Often gross hematuria
- Digital rectal examination (DRE): symmetrically enlarged, smooth (no nodules), firm, nontender prostate with rubbery or elastic texture
To remember the symptoms of BPH, think “FUNWISE”: Frequency, Urgency, Nocturia, Weak stream /hesitancy, Intermittent stream, Straining to urinate, and Emptying (not emptying completely, terminal dribbling).
Laboratory studies: mainly to assess complications and rule out accompanying or differential diagnoses
- Urinalysis and urine culture: to rule out urinary tract infection and hematuria
- (PSA): Indicated in men with ≥ 10 year life expectancy to identify co-existent prostate cancer, if present
- Renal parameters (blood urea nitrogen, creatinine, electrolyte levels): Indicated in men with high post void resides
- Maximal urinary flow rate measurement (Uroflowmetry)
- Other causes of prostatic enlargement: , ,
- Other causes of
The differential diagnoses listed here are not exhaustive.
- Watchful waiting (behavior modifications): indicated as sole therapy in patients with mildly symptomatic BPH; as supplemental therapy in patients requiring medical therapy
Medical therapy (monotherapy/combination of two drugs)
- Mild BPH
- Uncomplicated moderate BPHwith minimal discomfort due to symptoms
- First-line: alpha-blockers (e.g., , , , ) inhibit α1 receptors (α1A receptors) of the bladder neck and the prostatic urethra → relaxation of the smooth muscle of the bladder neck and the urethra → decreased resistance to urinary outflow → symptomatic improvement
- 5-alpha-reductase inhibitor (e.g., finasteride, dutasteride) prevent the conversion of testosterone to DHT → lower intraprostatic DHT levels → decreased prostatic growth and increased prostatic apoptosis and involution → improvement of LUTS
- /anticholinergics (e.g., , , etc.): Indicated in patients with irritative symptoms without elevated post void residuals
- Phosphodiesterase type 5 inhibitors (e.g., tadalafil): indicated in patients with mild/moderate BPH symptoms and erectile dysfunction
- Severe BPH symptoms with/without complications
- Moderate BPH with complications (see below)
- Transurethral resection of the prostate (TURP)
- Transurethral incision of the prostate (TUIP): indicated in patients with small prostates with obstructive symptoms or those at high risk for surgical complications
- Laser ablation, radiofrequency ablation, microwave thermotherapy are other newer techniques used for prostate tissue resection.
- Open/laparoscopic/robotic prostatectomy: Indicated in patients with very large prostates (> 75 g)
Since the peripheral zone (in which prostate cancer can develop) is left intact in TURP, the risk of developing prostate cancer after TURP is the same as that of the general male population. Normal PSA screening protocol should be followed.
- Bladder calculi
We list the most important complications. The selection is not exhaustive.