Lecture 15: Benign Diseases of the Prostate and Urinary Tract Obstruction Flashcards
definition of benign prostatic hyperplasia
BPH refers to the non-cancerous enlargement of the prostate gland, particularly the transition zone, leading to the compression of the urethra and subsequent lower urinary tract symptoms (LUTS).
BPH aetiology
The exact cause of BPH remains unclear, but age and hormonal changes, particularly the influence of dihydrotestosterone (DHT), play pivotal roles in its development. Genetic predisposition and lifestyle factors may also contribute.
BPH pathophysiology
BPH is characterised by the nodular overgrowth of prostatic tissue, predominantly in the transition zone. This growth impinges on the prostatic urethra, causing dynamic and static obstruction, leading to urinary symptoms.
signs and symptoms of BPH
- hesitancy
- weak stream
- frequency
- urgency
- nocturia
- sensation of incomplete emptying
BPH investigations
- urinalysis: MSSU, flow-rate study etc.
- international prostate symptom score (IPSS): assessing the severity of LUTS
- digital rectal examination (DRE): assess prostate size, consistency and the presence of nodules.
- prostate specific antigen (PSA) test: to rule out prostate cancer and guide further investigations.
- 2 week wait referral PSA levels are above age-specific range.
BPH management
- watchful waiting: for mild symptoms, particularly in older individuals.
- lifestyle modifications: fluid restriction, avoidance of caffeine and alcohol, and timed voiding.
- alpha-blockers (e.g. tamsulosin): for dynamic obstruction, provides symptom relief.
- 5-alpha reductase inhibitors (e.g. finasteride): to reduce prostate size.
- minimally invasive therapies: transurethral resection (TURP) of the prostate or laser prostatectomy.
- surgical intervention
describe the international prostate symptom score (IPSS)
- used to assess the severity of LUTS.
- score 20-35: severely symptomatic
- score 8-19: moderately symptomatic
- score 0-7: mildly symptomatic
how do alpha-blockers work to treat LUTS due to BPO?
- smooth muscle of bladder neck (i.e. intrinsic urethral sphincter) and prostate innervated by sympathetic alpha-adrenergic nerves (mostly alpha-1a subtype).
- alpha-blockers cause smooth muscle relaxation and antagonise the ‘dynamic’ element to prostatic obstruction.
how do 5alpha-reductase inhibitors treat BPE?
- 5alpha-reductase converts testosterone to dihydrotestosterone.
- blocks this conversion.
- reduces prostate size and reduces risks of progression of BPE (but only if > 25cc prostate)
- also reduces LUTS (to a lesser extent than alpha-inhibitors, combination therapy is the most effective)
what procedure is the gold-standard for surgical management of BPE causing BOO?
- transurethral resection of prostate (TURP) (except for prostate size > 100cc)
- can be done using glycine (monopolar TURP) or saline (bipolar TURP)
TURP complications
- bleeding
- infection
- retrograde ejaculation
- stress urinary incontinence
- prostatic regrowth causing recurrent haematuria or BOO
why can TURP not be performed if the prostate size > 100cc
High risk of intra-operative or post-operative complications including:
- bleeding
- fluid overload
- hypothermia
- TUR syndrome (triad of dilutional hyponatraemia, fluid overload and glycine toxicity) (only for monopolar TURP).
what are the complications of BPO?
- progression of LUTS
- acute urinary retention
- chronic urinary retention
- urinary incontinence (overflow)
- UTI
- bladder stone
- renal failure from obstructed ureteric outflow due to high bladder pressure
discuss the treatment of complicated BPO
most patients will require surgery:
- e.g. cystolithoplaxy and TURP for patients with BPO and bladder stones
alternative treatment options (e.g. for patients unfit for surgery):
- long-term urethral or suprapubic catheterisation
- clean intermittent self-catheterisation
if the upper urinary tract is obstructed, USS will show what?
- hydronephrosis
- hydroureter
- however, cause of obstruction may not be visualised (obscured by gas)
