This document provides an overview of benign prostatic hyperplasia (BPH) including its etiology, pathology, clinical findings, and investigation. It notes that BPH begins as microscopic nodules in the transitional zone of the prostate that can grow and compress surrounding tissue. Common symptoms include urinary frequency, urgency, and nocturia. Evaluation involves assessment of lower urinary tract symptoms, digital rectal exam, urinalysis, post-void residual measurement, and in some cases urodynamic testing. BPH is a common condition among older men that results from changes in hormone levels and growth factors.
3. It is a histologic diagnosis characterised by proliferation of the
cellular elements of the prostate.
In men 20 to 30 years of age, the prostate weighs about 20 gm and
generally weighs more after 50. It is a common problem among
older men, aged > 50 however, it is an infrequent cause of death.
BPH is considered to be the
most common benign internal
neoplasm of the adult male.
Introduction
4. The prevalence of histologically diagnosed prostatic hyperplasia
increases from
8 percent in men aged 31 to 40,
40 to 50 percent in men aged 51 to 60,
>80 percent in men older than age 80
5. BPH is considered a normal part ageing process in men, serum testosterone
level decreases slowly but the level of oestrogenic steroids is not decreased
equally.
According to theory, this increased levels of oestrogenic steroids cause for
prostate enlargement.
The secretion of intermediate peptide growth factors also plays a part in the
development of BPH.
Etiology
6. Androgens are necessary for both normal and abnormal
development of the prostate.
Testosterone is converted to a more potent androgen,
dihydrotestosterone (DHT), by the enzyme 5-α reductase type 2.
The type 1 form of the enzyme is present in liver and skin.
7. Men who congenitally lack 5-α reductase type 2 enzyme have
normal serum testosterone levels but lack dihydrotestosterone.
Those with this disorder have a rudimentary prostate
throughout life but rarely experience bladder outlet obstruction
secondary to BPH.
These findings suggest that the active androgen, DHT, is
important in promoting growth of prostate that would
eventually lead to symptomatic BPH.
8. Prostatic hyperplasia increases urethral resistance causing
compensatory changes in bladder function.
Obstruction induced changes in detrusor function, compounded
by age related changes in both bladder and nervous system
function lead to
Urinary frequency
Urgency
Nocturia
Pathophysiology
9. McNeal demonstrated that BPH first
develops in the peri-urethral
transition zone of the prostate.
BPH affects both glandular
epithelium and connective
tissue stroma.
Pathology
10.
11. Transitional zone surrounds the urethra proximal to the ejaculatory ducts.
Central zone surrounds the ejaculatory ducts and projects under the
bladder base.
12. Peripheral zone constitutes the bulk of the apical, posterior, and lateral aspects of
the prostate.
Anterior fibromuscular stroma extends from the bladder neck to the striated
urethral sphincter
13. The zonal anatomy of the prostate is clinically important
because most carcinomas arise in the peripheral zone, whereas
BPH affects the transitional zone, which may grow to form the
bulk of the prostate.
BPH begins as micronodules in the transitional zone which grow
and coalesce to form macronodules around the inferior margin
of the pre-prostatic urethra, just above the verumontanum.
14. Macronodules in turn compress the surrounding normal tissue
of the peripheral zone postero-inferiorly, creating a ‘false
capsule' around the hyperplastic tissue which coincidentally
provides a plane of cleavage for its surgical enucleation.
16. As the transitional zone grows, it produces the appearance of
‘lobes' on either side of the urethra. In due course, these lobes
may compress or distort the preprostatic and prostatic parts of
the urethra and produce symptoms.
The central zone surrounding the ejaculatory ducts is rarely
involved in any disease.
17. BPH typically affects the submucous group of glands in the
transitional zone, forming a nodular enlargement.
This overgrowth compresses the PZ glands into a false capsule
and causes the appearance of the typical ‘lateral’ lobe.
18. The unique feature of human prostate is the presence of prostatic
capsule- plays an important role in the development of Lower urinary
tract symptoms.
The capsule transmits the “pressure” of tissue expansion to the
urethra and leads to an increase in urethral resistance.
19.
20. In the Late Stage of BPH
• When BPH affects the Central
Zone glands, a ‘middle’ lobe
develops that projects up into
the bladder within the internal
sphincter
21. The relationship between anatomical
prostatic enlargement, lower urinary
tract symptoms (LUTS) and
urodynamic evidence of bladder
outflow obstruction (BOO) is complex
Effects of BPH
22. Diagram showing the relationship between histologic hyperplasia of the prostate (BPH), lower
urinary tract symptoms (LUTS), benign prostate enlargement (BPE), and bladder outlet obstruction
(BOO). The size of the circles does not represent actual proportions but rather illustrates the partial
overlap between the different disease definitions.
23. The pathophysiology of
benign prostatic
hyperplasia (BPH)
involves complex
interactions between
urethral obstruction,
detrusor function and
dysfunction, and urine
production.
24. Prostatic hyperplasia increases urethral resistance, resulting in
compensatory changes in bladder function.
However, the elevated detrusor pressure required to maintain
urinary flow in the presence of increased outflow resistance
occurs at the expense of normal bladder storage function.
25. Chronic bladder outlet obstruction (BOO) secondary to BPH
leads to
Urinary retention
Renal insufficiency
Recurrent UTI
Bladder wall thinning and loss of function due to constant
distension
Haematuria
Vesical calculi
26. The prostatic urethra is lengthened (twice its normal length), but it is
not narrowed anatomically.
The normal posterior curve may be so exaggerated- requires a
curved catheter to negotiate it.
When only one lateral lobe is enlarged, distortion of the prostatic
urethra occurs.
Effects of BPH on the Urethra
27. If BPH causes BOO, the musculature
of the bladder hypertrophies to
overcome the obstruction and
appears trabeculated .
BPH is associated with increased
blood flow, and the resultant veins
at the base of the bladder causes
haematuria.
Effects of BPH on the Urinary Bladder
28. Not all symptoms of disturbed voiding in ageing men should
therefore be attributed to BPH causing BOO.
Pathophysiologically, BOO may be caused in part by increased
smooth muscle tone, which is under the control of a-adrenergic
agonists
Lower Urinary Tract Symptoms (LUTS)
29. The following conditions can coexist with BOO:
oIdiopathic detrusor overactivity.
oNeuropathic bladder dysfunction as a result of diabetes, strokes,
Alzheimer’s disease or Parkinson’s disease.
oDegeneration of bladder smooth muscle giving rise to impaired voiding
and detrusor instability;
oBOO due to BPH.
30. Hesitancy (worsened if the bladder is very full)
Poor flow (unimproved by straining)
Intermittent stream – stops and starts
Dribbling (including after micturition)
Sensation of poor bladder emptying
Episodes of near retention
Voiding symptoms
32. This is a urodynamic concept
based on the combination of
low flow rates in the presence
of high voiding pressures.
Diagnosed definitively only by
pressure-flow studies.
Bladder Outflow Obstruction
33. Flow rates provide a useful guide for everyday clinical
management.
Urodynamically proven BOO may result from:
BPH
Bladder neck stenosis
Bladder neck hypertrophy
Prostate cancer
Urethral strictures
Functional obstruction due to neuropathic conditions
34. Effects of BOO on the Bladder
Decrease in urinary flow rates :
For a voided volume > 200 ml, a peak flow rate of > 15 ml/s is normal, 10–15 ml/s is equivocal
and < 10 ml/s is low.
35. Increase in voiding pressures
:
Pressures > 80 cmH2O
are high, pressures
between 60 and 80
cmH2O are equivocal and
pressures < 60 cm H2O
are normal.
36. Acute retention of urine
Chronic retention
Impaired emptying of bladder
Haematuria
Complications of BOO
37. Other than pain from retention, pain is not a symptom of BOO
Its presence should prompt the exclusion of acute retention,
urinary infection, stones, carcinoma of the prostate and
carcinoma in situ of the bladder
38. It is critical to exclude causes of LUTS other than BPH before medical or
surgical treatment.
The differential diagnosis of lower urinary tract symptoms in addition to
BPH includes the following:
Urethral stricture
Bladder neck contracture
Carcinoma of the prostate
Carcinoma of the bladder
Bladder calculi
Urinary tract infection and prostatitis
Neurogenic bladder
39. History:
Symptom assessment:
The International Prostate Symptom Score (IPSS) is
recommended scoring system for the baseline assessment
of symptom, severity in men presenting with LUTS
Assessment of the Patient with LUTS
40.
41. Generally WNL
Chronic retention- distended bladder
Loss of the transverse supra pubic skin crease
Examination of the external urethral meatus is done to exclude
stenosis or a palpable urethral mass
Epididymides are palpated for signs of inflammation
Abdominal Examination
42. The posterior surface of the prostate is
smooth, convex and firm in consistency.
The rectal mucosa can be made to move
over the prostate.
Residual urine may be felt as a fluctuating
swelling above the prostate.
Considerable amount of residual urine if
present, pushes the prostate downwards,
making it appear larger than it is.
Digital Rectal Examination
43. To eliminate neurological conditions like diabetes mellitus, tabes
dorsalis, disseminated sclerosis, cervical spondylosis, Parkinson’s
disease may mimic prostatic obstruction.
Examination of perianal sensation and anal tone is useful in
detection of an S2 to S4 cauda equina lesion.
Nervous System
44. A urinalysis should be done either by using a dipstick test or
microscopic examination of the spun sediment to rule out UTI
and haematuria, either of which strongly suggest a non-BPH
pathologic process as a cause of symptoms.
Urine cytology should always be requested in men with severe
irritable symptoms and dysuria, especially if they have a
smoking history. Carcinoma in-situ of the bladder is a diagnosis
that may have serious consequences if overlooked.
Urinalysis
45. Postvoid residual urine volume is the amount of fluid remaining in
the bladder immediately after the completion of micturition.
Studies indicate that PVR urine volume normally ranges from 0.09 to
2.24 mL, with the mean being 0.53 mL (Hinman and Cox, 1967).
Seventy-eight percent of normal men have PVR volumes of less than
5 mL, and 100% have volumes of less than 12 mL(DiMare et al, 1963).
USG & Postvoid Residual Urine Volume
46. Traditionally, urologists have assumed that increasing amounts
of PVR urine denote BPH progression and are thus an
“indication” for surgery.
47.
48. Normally present in Serum but if > 2.5–4 nmol/L, then
transrectal ultrasound scanning (TRUS) plus multiple transrectal
biopsies (10 biopsies) should be considered.
Serum Prostate – Specific Antigen
49. Special flow rate clinic.
Coupled with ultrasound measurement
of post-void residual urine
Flow Rate Measurement
50.
51. A, Normal cystoscopic appearance of the prostate in a young man.
B, Moderate BPH, viewed cystoscopically
52. Q- In which zone of the prostate does hypertrophy begin
A) Peripheral zone
B) Central zone
C) Transitional zone
D) Fibromuscular Stroma
MCQ
Answer- C) Transitional zone
Reference- Bailey & Love’s Short Practice of Surgery, 26th edition,
page #1342.
53. Bailey and Love’s Short Practice of Surgery, 26th Edition
Sabiston Textbook of Surgery, 19th Edition
Campbell – Walsh Urology, 10th Edition
Robbins Basic Pathology, 9th Edition
Gray’s Anatomy, 40th Edition
References