Benign prostatic hypertrophy

Pathophysiology

Proposed to occur secondary to increasing oestrogenic stimulus over time
Affects both glandular epithelium and connective tissue
Typically affects submucosal glands in transitional zone, forming a nodular enlargement
Complex relationship between BPH, BOO and LUTS
Bladder outlet obstruction:
- Urodynamic concept - low flow rates in the presence of high voiding pressures
- Can result from:
  - BPH
  - Bladder neck stenosis
  - Bladder neck hypertrophy
  - Prostate cancer
  - Urethral strictures
  - Functional obstruction due to neuropathic conditions
- Consequences:
  - Decompensated bladder - less efficient detrusor contraction, residual urine
  - Irritable bladder with decrease in functional capacity
  - Acute/chronic urinary retention
  - Impaired bladder emptying
  - Haematuria (complication of BPH or otherwise)
  - Pain is not a symptom of BOO, other than AUR
Anatomical effects of BPH:
- Urethra - lengthened prostatic urethra, but not narrowed
- Bladder - if BPH causes BOO, the musculature of the bladder hypertrophies to overcome the obstruction and appears trabeculated. Significant BPH is a/w increased blood flow, and the resultant veins at the base of the bladder are apt to cause haematuria.

Important to acknowledge that BPH can coexist with other pathologies such neuropathic bladder, idiopathic detrusor overactivity and BOO
See 'urologic symptoms' for a full description of LUTS
Post-micturition dribbling is not a consequence of BOO and does not usually improve with prostatectomy
Can use International Prostate Symptom Score for a semi-objective assessment
Examination
- Loss of transverse suprapubic skin crease due to large bladder
- DRE: smooth posterior surface, which is convex and typically elastic. The rectal mucosa should be able to move over the prostate. An inability to get to prostate base implies a volume of at least 50mL.

Urinalysis
Urine MCS
UEC
PVR
?PSA - if an early diagnosis of prostate cancer would influence treatment - those under 70yo and positive family history
- If higher than age-adjusted cut-off, will need TRUS + biopsies
?urodynamics
Upper tract imaging may not be necessary in men with straightforward symptoms
Cystourethroscopy will normally be done at the time of TURP

Acute retention with no other cause
Chronic retention and renal impairment
- PVR >200mL
- Raised blood urea
- Hydroureter/hydronephrosis
Complications of BOO
- Stone
- Infection
- Diverticulum
Haemorrhage
Elective prostatectomy for severe symptoms
- Increasing difficulty in micturition
- Hesitancy
- Poor stream (<10mL/s max flow rate)
- Frequency day and night (not a strong indication for prostatectomy alone)
- Failed a preliminary trial of medical therapy

Non-operative
- Fluid restriction
- Reduction in caffeine
- Duodart - results in a 25% shrinking of prostate if taken for a year, and an average 20% improvement in symptom scores. And men often end up needing surgery anyway.
Operative
- TURP - results in significant improvements in max flow rate and a 75% improvement in symptoms scores
- Very large prostates may require open prostatectomy or HOLEP (Holmium laser enucleation of the prostate)
- Risks:
  - Secondary haemorrhage occurs after discharge, often with clot retention. Needs readmission and washout.
  - Retrograde ejaculation - about 65% of men
  - Erectile impotence - about 5% of men, and usually those whose potency is waning regardless
  - Failure to improve symptoms - worse in those who only have mild symptoms, or those with weak bladder contraction anyway
  - Risk of reoperation - about 15% after 10 years