Urinary Tract Obstruction

Question 1

What is the transition zone of the prostate gland?

Answer 1

• The transition zone surrounds the part of the urethra that passes through the prostate
• The zone gets bigger as men age

Question 2

What is benign prostatic hyperplasia?

Answer 2

• Fibromuscular and glandular hyperplasia that is part of the normal aging process in men. Predominantly affects the transition zone
• 50% of men at 60yrs, 90% of men at 85yrs

Question 3

What are some signs of bladder outflow obstruction on physical examination?

Answer 3

• Palpable bladder
• Enlarged prostate
• Phimosis (can’t pull foreskin back) / external urethral meatal stricture

Question 4

What are some investigations that can be done for suspected bladder outflow obstruction?

Answer 4

• MSSU
• Flow rate study
• Post-voidal bladder USS
• Urinalysis (haematuria / signs of UTI)

Question 5

How does a flow rate test work? What value indicates probably bladder outflow tract obstruction?

Answer 5

• Measure the flow time and max flow velocity of urine via a contactless machine
• If Qmax (max flow) is < 10mL/s there is 90% chance of having bladder outflow obstruction

Question 6

What are the main pharmacological agents used to treat benign prostatic obstruction?

Answer 6

• Alpha blockers

- 5 alpha reductase inhibitors (finasteride / dutasteride)

Question 7

How do alpha blockers treat benign prostatic obstruction?

Answer 7

alpha blockers cause relaxation of the smooth muscle of the bladder neck and prostate

• Innervated by alpha 1a adrenergic nerves

Question 8

What is the function of 5 alpha reductase inhibitors? How does this treat benign prostatic obstruction?

Answer 8

Converts testosterone to DHT:

• reduces prostate size and reduces risks of progression of BPE (but only if >25cc prostate)
• also reduces LUTS (but not as effective as alpha blockers)
• combination therapy of 5ARIs + alpha blockers most effective in reducing risk of progression of BPE
• can also reduce prostatic vascularity and hence reduces haematuria due to prostatic bleeding

Question 9

What are some surgical options for treatment of benign prostatic obstruction?

Answer 9

TURP (prostate size <100cc)

Open retropubic or transvesical prostatectomy (prostate size >100cc)

Endoscopic ablative procedures

Question 10

What is TURP surgery?

Answer 10

• Transurethral resection of prostate
• Cutting away a section of the prostate via access through the urethra. Gold standard
• For prostate sizes <100cc

Question 11

What are some common complications associated with benign prostatic obstruction?

Answer 11

• 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

Question 12

What are some common signs of upper urinary tract obstruction?

Answer 12

• Pelvi-ureteric junction (PUJ)(where renal pelvis becomes the ureter)
• Ureter
• Vesico-ureteric junction (VUJ)

Question 13

What are some symptoms and signs of upper urinary tract obstruction?

Answer 13

• Pain
• Haematuria
• Palpable mass
• Infection & sepsis / renal failure

Question 14

What are some common sites of lower urinary tract obstruction?

Answer 14

• bladder neck
• prostate
• urethra
• urethral meatus
• foreskin (e.g. phimosis)

Question 15

What are some common presentations of lower urinary tract obstruction?

Answer 15

Lower urinary tract symptoms (LUTS)
Acute / Chronic urinary retention
Recurrent urinary tract infection and sepsis
Haematuria
Formation of bladder stones
Renal failure

Question 16

What may be a necessary immediate intervention for lower urinary tract obstruction?

Answer 16

• Urethral catheterization
  or
• Suprapubic catheterization