PBL 1

Question 1

outline the pathophysiology behind the cell proliferation in benign prostatic hyperplasia?

Answer 1

oestrogens and androgens enter cells and bind to receptors in the nucleus to inhibit apoptosis and akkow lumen and basal cells within the prostate to proliferate. After the age of 30 decrease but 5 alpha reductase levels increase so we got more formation of dihydrotestosterone which is 10x more potent than hyprplasia and therefore causes hyperplasia.

Question 2

what causes the narrowing of the urethral canal in BPH?

Answer 2

the enlargement of the prostate squeezing on it and the formation of hyperplastic nodules in the periurethral zone.

Question 3

how prevalent is BPH at the age of 90?

Answer 3

90%

Question 4

what are some risk factors for BPH?

Answer 4

age >40
Fhx BPH
heart and circulatory disease
beta blocker use
obesity
diabetes type 2
lack of physical exercise
erectile dysfunction

Question 5

what are some complications of BPH?

Answer 5

bladder damage due to hypertrophy caused by urine in bladder making it dilate and smooth muscles contracting harder in response
urinary retention
UTIs due to post void residual volume becoming stagnant
hydronephrosis due to build up of urine

Question 6

what are the signs and symptoms of BPH?

Answer 6

frequency, urgency, nocturia, dysuria, emptying bladder feels incomplete, difficulty starting and stopping urine flow, dribbling, weak stream

Question 7

why would we do a digitial rectal exam in BPH?

Answer 7

to determine if the prostate is enlarged or nodular - in BPH it should feel enlarged, rubbery, like a bulge

Question 8

what are blood tests done for in BPH?

Answer 8

to see if there is increases in prostate specific antigen, electrolytes, blood urea nitrogen and creatinine

Question 9

why do we do urinanalysis in BPH?

Answer 9

Analyzing a sample of your urine can help rule out an infection or other conditions that can cause similar symptoms.

Question 10

what imaging do we do in BPH?

Answer 10

transrectal ultrasound, cystoscopy, maybe MRI

Question 11

what are some lifestyle changes you can do to relive BPH symptoms?

Answer 11

drink less caffeiene, drink less fluid in the evening, remember to empty your bladder, double voiding to try to help empty your bladder, check meds, eat more fibre, use pads and bladder training

Question 12

what are the 6 classes of drugs used to treat BPH?

Answer 12

alphablockers
PDE5 inhibitors
anticholinergics
5 alpha reductase inhibitors
diuretics 
desmopressins

Question 13

how do alpha blockers work to reduce BPH?

Answer 13

they inhibit alpha adrenergic receptors on smooth muscle, stopping the constriction effects and allowing a decrease in resistance along bladder neck, prostate and urethra. This allows urine to pass through more easily

Question 14

how do 5 alpha reductase inhibitors work for BPH?

Answer 14

they reduce the formation of dihydrotestosterone which prevents the proliferation of prostate tissue and improves the flow of urine

Question 15

how do PDE5 inhibitors work?

Answer 15

they relax smooth muscle fibres of the bladder and prostate, improving flow

Question 16

how do anticholinergics work to reduce BPH?

Answer 16

they relax the bladder muscle if its overactive

Question 17

how do diuretics help in BPH?

Answer 17

they increase the amount of urine produced so if used in the day they can prevent chances of nocturia

Question 18

how can desmopressins be used in BPH?

Answer 18

Desmopressins slow down urine production so less urine is produced at night.

Question 19

what is a transurethral resection of the prostate?

Answer 19

a non-invasive surgical procedure cutting away sections of the prostate - note this is not permenant and prostate will grow back if androgen levels remain high

Question 20

what is an open prostatectomy?

Answer 20

the surgical removal of the prostate gland

Question 21

why dont we screen for PSA in the UK?

Answer 21

we dont believe the risks outweight the benefits…

• PSA tests are not sensiitive - PSA levels rise in bikers, after sexual intercourse, after catheter use
• 1/7 prostate cancer cases have normal PSA = not specific
• Test can show slow-growing cancer that will never affect the indidvidual - just worries them
• Treating early is beneficial but the side effects are so serious men often wait till its absolutely necessary
• Biopsies have risks of bleeding, infection and pain

Question 22

what do we do instead of PSA screening in the UK?

Answer 22

there is an informed choice programme called prostate cancer risk management, for health men >50 who query their GP about PSA testing. It aims to give men good information on the pros and cons on the PSA test.

Question 23

what is sensitivity?

Answer 23

the chance a test can detect a specific disease in people who have that disease
true positives / total diseased

Question 24

what is specificty?

Answer 24

the chance a test can detect negative results for a specific disease in people who dont have the disease
true negatives / total non-diseased

Question 25

what are some examples of alpha adrenergic receptor blockers?

Answer 25

tamsulosin, doxazosin and tetrazosin

Question 26

what are some examples of PDE5 inibitors?

Answer 26

sildenafil and tadalafil

Question 27

what are some examples of 5 alpha reductase inhibitors?

Answer 27

finadteride

Question 28

what is micturition?

Answer 28

the release of urine from the urinary bladder once its full, down the urethra and outside the body

Question 29

what are the 3 phases of micturition?

Answer 29

the storage phase- detrusor relaxed and external sphincter contracted
the voiding phase - detrusor contracts and external sphincter and oelvic floor relax
termination of voiding phase - residual urine above lebel of external sphincter is squeezed back into the bladder as the external sphincter and pelvic floor contracts

Question 30

what produces peristalsis in the ureter?

Answer 30

urine stretching the calyces in the kidneys

Question 31

Describe how we empty the bladder once the bladder is full

Answer 31

stretch receptors in the bladder well are activated
sensory fibres from the pelvic nerve pick this up and take it to the sacral spinal cord
S2 3 and 4 (parasympathetic) act on M3 receptors on detrusor muscle via ACh causing contraction and they relax the inertnal sphincter muscle via the alpha 1 receptor
this causes emptying of the bladder

Question 32

outline the higher brain centres involved in voiding?

Answer 32

when the bladder is full we get a signal to the pontine micturition centre. when its not a convenient time to urinate the cortex can inhibit the pontine micturition centre which sends a signal down the pudendal nerve to release ACh and act on nicotinic receptor in external yrethral sphincter to keep it contracted.
when you wish to urinate, this inhibitin is removed

Question 33

outline the reflex for storing urine?

Answer 33

hypogastric nerves (sympathetic) act on beta 3 receptors in the detrusor muscle to cause relaxation. this nerve also acts on the alpha 1 receptors on the external urethral sphincter via NA to cause contraction.