PBL 8 - BPH Flashcards
What is a common outcome of prostate enlargement besides its impact on
urination? What test was used in the PBL to screen for it?
Possibility of infection due to stasis of urine [1/2 mark]
Urine culture [1
) 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
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]
Explain how the tamsulosin and finasteride work and how it relieved the
patient’s symptoms
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]
What type of muscle in lower urinary tract
All smooth muscle
except EUS - striated
What epithelium is the bladder
Transitional epithelium
What is the trigone
region of smooth muscle bounded by a triangle formed from orifices of ureters and urethra
What zone does BPH occur in
Transitional zone
Function of splanchnic pelvic nerve
Parasympathetic, Release Ach → Muscarinic M3 receptors → detrusor contraction
Function of pudendal nerve
– Somatic, sacral, Somatic pudendal nerves release Ach which stimulates nicotinic receptors on external sphincter to contract – skeletal muscle so voluntary control
Function of hypogastric nerve
=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
Sensory pelvic nerve
Afferent from detrusor muscle, stimulated when bladder is stretched
What nerve is responsible for urine retention and urination
Hypogastric/SNS - retention
Parasympathetic - Urination
What occurs when bladdder is full
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
Why do a urine culture
Infection
UTI
Urea and creatinine
Kidney damage due to back pressure
Digital rectal exam
insert finger into rectum, allows to tell difference between smooth or irregular surface of prostate (possibility of malignancy
Prostate specific antigen test
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
High post-void residual volume
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
oTHER ways of diagnosis
CT urogram
Prostate biopsy
What causes symptoms in BPH
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)
What are symptoms of BPH
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
Surgery for BPH
TURP (gold standard, electric loop carves out prostate chips)
Drugs - tamsulosin and finasteride
MoA of tamsulosin
Selective alpha 1 adrenergic receptor antagonist
relaxes internal sphincter and detrusor muscle to make it easier to urinate
MoA finasteride
Type 2 and type 3 5a-reductase inhibitor (shrinks)
5α-reductase converts testosterone to dihydrotestosterone (DHT)
What is DHT function
androgen responsible for prostatic growth and enlargement
