PBL 8 - BPH

Question 1

What is a common outcome of prostate enlargement besides its impact on
urination? What test was used in the PBL to screen for it?

Answer 1

Possibility of infection due to stasis of urine [1/2 mark]

Urine culture [1

Question 2

) Name two important tests (performed in this scenario) for which positive results
would indicate the need for a biopsy. What would be the purpose of the biopsy? [2
mark

Answer 2

Biopsy is indicated when the PSA is significantly high or significantly rising over
time [1/2]. OR there is suspicious irregularity of the prostate on digital rectal
examination [1/2]. Examination of such biopsies can help diagnose or rule out
prostate cancer [1]

Question 3

Explain how the tamsulosin and finasteride work and how it relieved the
patient’s symptoms

Answer 3

Tamsulosin is an α-adrenergic receptor blocker [1 mark]. It works by relaxing
bladder neck muscles and muscle fibers in the prostate itself and make it easier to
urinate. This opposes the restriction on the bladder neck outlet caused by an
enlarged prostate [1 mark]
Finasteride is a competitive inhibitor of 5α-reductase [1 mark]. 5α-reductase is the
androgen primarily responsible for prostatic growth and enlargement [1 mark]

Question 4

What type of muscle in lower urinary tract

Answer 4

All smooth muscle

except EUS - striated

Question 5

What epithelium is the bladder

Answer 5

Transitional epithelium

Question 6

What is the trigone

Answer 6

region of smooth muscle bounded by a triangle formed from orifices of ureters and urethra

Question 7

What zone does BPH occur in

Answer 7

Transitional zone

Question 8

Function of splanchnic pelvic nerve

Answer 8

Parasympathetic, Release Ach → Muscarinic M3 receptors → detrusor contraction

Question 9

Function of pudendal nerve

Answer 9

– Somatic, sacral, Somatic pudendal nerves release Ach which stimulates nicotinic receptors on external sphincter to contract – skeletal muscle so voluntary control

Question 10

Function of hypogastric nerve

Answer 10

=Releases NA which binds to B3 receptors on detrusor →relax
=A-1 on internal sphincter → contract
Post-ganglionic sympathetic, pre-ganglionic from thoracolumbar region (T12 – L2) → synapse at ganglion → release NTS →to post ganglionic fibres e.g hypogastric

Question 11

Sensory pelvic nerve

Answer 11

Afferent from detrusor muscle, stimulated when bladder is stretched

Question 12

What nerve is responsible for urine retention and urination

Answer 12

Hypogastric/SNS - retention

Parasympathetic - Urination

Question 13

What occurs when bladdder is full

Answer 13

o Stretch in detrusor → Sensory pelvic nerves detect stretch → Increased firing to sacral region of SC → Fast impulses up to pontine micturition centre → Stimulates neurons → Inhibits hypogastric sympathetic nerve so no relaxation of detrusor and relaxation of a-1 so internal sphincter relaxes → Stimulate pelvic efferent nerves → Contraction of detrusor on M3 → inhibition of pudendal → no contraction of external sphincter so it is relaxed

Question 14

Why do a urine culture

Answer 14

Infection

UTI

Question 15

Urea and creatinine

Answer 15

Kidney damage due to back pressure

Question 16

Digital rectal exam

Answer 16

insert finger into rectum, allows to tell difference between smooth or irregular surface of prostate (possibility of malignancy

Question 17

Prostate specific antigen test

Answer 17

Prostate secretes PSA (liquefies semen). An enlarged prostate causes PSA to rise, rise can indicate prostate cancer however normal levels do not rule out the presence of cancer. PSA increases with age and a level >4 ug/L in a younger age group may be cancer

Question 18

High post-void residual volume

Answer 18

Measures if urine is still in the bladder after micturition – a high volume would indicate an outflow obstruction. In chronic retention it can lead to renal failure.
= Can measure by ultrasound or catheterisation

Question 19

oTHER ways of diagnosis

Answer 19

CT urogram

Prostate biopsy

Question 20

What causes symptoms in BPH

Answer 20

o The gland stretches and distorts the urethra and obstructs bladder outflow, can compress on urethra
o Musculature hypertrophies so pressure increases in the bladder to overcome the obstruction –> Bladder becomes dilated and the muscle becomes hypotonic
 Causes the patient’s symptoms (thinks that the bladder is stretched all the time)

Question 21

What are symptoms of BPH

Answer 21

Trouble starting to urinate
Weak stream
Strong need to urinate (Urgency) 
More than 8 times a day (frequency) 
Feels like bladder isnt empty after go
- advanced: burning/pain when you pee, blood in urine

Question 22

Surgery for BPH

Answer 22

TURP (gold standard, electric loop carves out prostate chips)
Drugs - tamsulosin and finasteride

Question 23

MoA of tamsulosin

Answer 23

Selective alpha 1 adrenergic receptor antagonist

relaxes internal sphincter and detrusor muscle to make it easier to urinate

Question 24

MoA finasteride

Answer 24

Type 2 and type 3 5a-reductase inhibitor (shrinks)

5α-reductase converts testosterone to dihydrotestosterone (DHT)

Question 25

What is DHT function

Answer 25

androgen responsible for prostatic growth and enlargement