BPH

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"benign prostatic hyperplasia"[MeSH Terms] AND treatment

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Here is a comprehensive overview of Benign Prostatic Hyperplasia (BPH) drawn from authoritative medical textbooks.

Benign Prostatic Hyperplasia (BPH)

Definition

BPH is the non-malignant proliferation of both stromal and glandular elements of the prostate gland. A prostate volume exceeding 30 mL is the threshold definition, though the degree of enlargement correlates poorly with symptom severity. The gland can enlarge 3- to 5-fold, reaching 60-100 g or more.

Goldman-Cecil Medicine, p. 1316
Robbins & Kumar Basic Pathology, p. 659

Epidemiology

Affects ~50% of men over age 50 (histologically)
Rises to ~90% by the 8th decade
Of those with histologic BPH, approximately 50% develop clinically significant lower urinary tract symptoms (LUTS)
Prevalence increases linearly between ages 40-80
Goldman-Cecil Medicine, p. 1316

Pathogenesis

BPH originates in the periurethral transition zone (distinguishing it from prostate cancer, which arises in the peripheral zone).

Androgen-driven mechanism:

Dihydrotestosterone (DHT) is the primary mediator - it is 10x more potent than testosterone
DHT is synthesized from testosterone in the prostate by 5α-reductase type 2
DHT binds nuclear androgen receptors and upregulates genes supporting stromal and glandular growth/survival
DHT-induced growth factors increase stromal cell proliferation and decrease epithelial cell apoptosis

Role of estrogens:

With aging, testosterone declines but estrogen levels remain stable or increase (via peripheral conversion)
Estrogens act synergistically with DHT to drive growth of both epithelial and stromal cells (both express estrogen receptors)

Note: BPH does not occur in males castrated before puberty or in those with genetic disorders blocking androgen activity - confirming the androgen-dependence.

Robbins & Kumar Basic Pathology, p. 659

Morphology

Gross:

Affects the transition zone, compressing the urethra to a slit-like orifice
Hyperplastic nodules vary in color/consistency depending on cellular content
May appear solid or contain cystic spaces (dilated glands)

Microscopic:

Nodules composed of variable proportions of proliferating glandular elements and fibromuscular stroma
Hyperplastic glands lined by two cell layers: tall columnar inner epithelial cells + peripheral flattened basal cells (key distinction from malignant glands, which lose the basal layer)
Glandular lumina often contain corpora amylacea (laminated proteinaceous secretory material)

BPH cystoscopic and gross specimen views - (A) normal prostatic urethra, (B) moderate BPH with lateral lobe enlargement on cystoscopy, (C) prostatic adenoma after open prostatectomy showing a small medial lobe (arrow) and large lateral lobes (130g specimen)

Sabiston Textbook of Surgery, p. 2824
Robbins & Kumar Basic Pathology, p. 659

Clinical Features

BPH causes bladder outlet obstruction (BOO) through two mechanisms:

Mechanical - physical compression of the urethra by enlarged gland
Dynamic - smooth muscle contraction in the prostatic stroma (alpha-1 adrenergic receptor-mediated)

LUTS are classified into three categories:

Category	Symptoms
Storage (irritative)	Urgency, frequency, nocturia, urge incontinence
Voiding (obstructive)	Hesitancy, weak/intermittent stream, straining, prolonged voiding
Post-void	Incomplete emptying, terminal dribbling

Complications:

Urinary retention (acute or chronic) - from complete obstruction
Recurrent UTI - residual urine acts as a culture medium
Bladder hypertrophy and distension
Hydronephrosis if untreated
Bladder calculi
Azotemia (elevated creatinine from back-pressure)
Sabiston Textbook of Surgery, p. 2824

Evaluation

History and International Prostate Symptom Score (IPSS)
Digital rectal exam (DRE) - assess prostate size and texture
Urinalysis - rule out infection, hematuria
PSA - in men with life expectancy >10 years (controversial; mainly to screen for concurrent prostate cancer)
Post-void residual (PVR) - if >300 cc, indicates significant retention regardless of symptoms
Uroflowmetry - assesses peak and average flow rates
Cystoscopy and urodynamics - for refractory or complex cases

Management

AUA 2023 Guideline Algorithm

Step 1: Lifestyle/Behavioral Modifications (all patients)

Fluid management (reduce caffeine, alcohol, evening fluids)
Bladder training
Manage contributing medications (e.g. diuretics)

Step 2: Medical Therapy

Drug Class	Mechanism	Examples	Key Side Effects
α1-blockers	Relax smooth muscle in bladder neck and prostate (α1a selective)	Tamsulosin, Alfuzosin, Silodosin, Doxazosin	Orthostatic hypotension, retrograde ejaculation, rhinitis
5α-reductase inhibitors (5-ARI)	Block testosterone → DHT conversion; reduce prostate volume over months	Finasteride (5-ARI type 2), Dutasteride (5-ARI type 1+2)	Reduces PSA ~50% (must adjust interpretation), sexual dysfunction
PDE5 inhibitors	Reduce smooth muscle tone via cGMP pathway	Tadalafil	Useful if concurrent ED
Combination therapy	α-blocker + 5-ARI	Superior to monotherapy for larger prostates

Note: 5-ARIs reduce serum PSA by approximately 50% - this must be accounted for when using PSA for prostate cancer screening. Multiply measured PSA x2 when patient is on a 5-ARI.

Step 3: Surgical Indications

Surgery is indicated when medical therapy fails or when objective complications arise:

Acute urinary retention
Bladder calculi
Azotemia / renal impairment
Recurrent UTIs
Recurrent hematuria

Surgical Options:

Procedure	Notes
TURP (Transurethral Resection of the Prostate)	Gold standard; monopolar, bipolar, or laser variants
HoLEP (Holmium Laser Enucleation)	Excellent for large glands
ThuLEP (Thulium Laser Enucleation)	Similar to HoLEP
PVP (Photoselective Vaporization)	Laser vaporization
Open simple prostatectomy	For very large adenomas (>100g)
Minimally invasive (microwave, radiofrequency, HIFU)	Office-based; inferior long-term outcomes vs TURP

TURP Complications:

Bleeding
TURP syndrome - dilutional hyponatremia from glycine absorption (monopolar only; eliminated with bipolar/laser using saline irrigation)
UTI
Urinary incontinence
Urethral stricture
Retrograde ejaculation
Sabiston Textbook of Surgery, p. 2824-2825
Goldman-Cecil Medicine, p. 1318

Key Distinctions: BPH vs Prostate Cancer

Feature	BPH	Prostate Cancer
Zone affected	Transition zone	Peripheral zone
Histology	Two cell layers (columnar + basal)	Loss of basal cell layer
DRE	Smooth, symmetric enlargement	Hard, irregular nodule
Malignant potential	None (not premalignant)	N/A
PSA elevation	Mild, proportional to size	Often disproportionately high

Robbins & Kumar Basic Pathology, p. 659

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