Urinary Obstruction Flashcards
Testosterone regulation

Benign prostatic hyperplasia
Hyperplasia of the prostate in response to excess levels of prolonged exposure to dihydrotestosterone.
Causes urinary obstruction and may cause reflux nephropathy and hydronephroses and predispose to pyelonephritis.
5α reductase inhibitors
Inhibit the synthesis of dihydrotestosterone from testosterone.
This blocks prostate hyperplasia, hormonal alopecia, and androgen-dependent excess body hair production
Prostate endocrinology diagram

Exocrine products of the prostate gland

Treating a prostate infection
Suprisingly few antibiotics can get into the prostate gland, so it is important to know a few that can:
- Erythromycin
- Sulfonamides
- Tetracycline
- Trimethoprim
- Fluoroquinolones
What is going on in this H and E slide?

Just normal prostate tissue!
Glands in a sea of stroma, with up to 30% stromal cells.
What is going on in this H and E slide?

BPH
Effect of estrogens on the prostate

Central and peripheral zones of the prostate
Central zones and transitional zones are more likely to undergo benign hyperplasia, where as peripheral zones are more likely to undergo malignant transformation.
The majority of prostate cancers arise from the peripheral zone.

Secondary effects of benign prostatic hyperplasia of the central and transitional zones
In response to prostatic hyperplasia and increased resistance in the prostatic urethra, the bladder smooth muscle will hypertrophy. This increases the force it can generate, but comes at the cost of compliance. Once compliance decreases below a certain critical threshold, “storage symptoms” will develop.
Storage symptoms (bladder)
- Frequency
- Urgency
- Nocturia
- Risk of reflux nephropathy and pyelonephritis
Ball-valve prostate
When the median lobe of the prostate enlarges, it may form a mass so large that it obstructs the outflow of the bladder when individuals bear down.
These individuals often describe that they have learned not to bear down fully when they urinate.
Syndrome of autonomic neuropathy affecting the bladder

Evaluating lower urinary tract symptoms (LUTS)

American Urological Association Symptom Score Index
A small questionaire that can be given to patients to assess the likelihood of LUT symptoms
International index of erectile function score (IIEF score)
Questionaire that may be given out to assess for erectile dysfunction
α-adrenergic receptor blockers for LUTS
- Block adrenoceptors on the bladder neck and the prostate and lead to relaxation of bladder muscle tone
- Tamsulosin is a selective agent, terazosin and doxazosin are not as selective
- May also cause erectile dysfunction, abnormal ejaculation, fatigue, nasal congestion, dry mouth and dry eyes
- While they may address discomfort, they do not inhibit the growth or progression of BPH /lower urinary tract symptoms, and so are not a cure
- Improvement of symptoms does not to reduce the risk of complications such as acute urinary retention or the need BPH-related surgery
5α -Reductase Inhibitors
- Inhibit 5α -reductase, which catalyzes conversion of testosterone to DHT
- Finasteride and dutasteride
- Reduce prostate volume. Response depends on prostate size
- Decrease risk of acute urinary retention and need for surgery
- Combination therapy with an alpha blocker leads to greater improvement in symptoms
- May precipitate erectile dysfunction, decrease libido, and produce gynecomastia
- May decrease PSA levels. Since it drops the PSA value to almost half, the actual number needs to be adjusted, accordingly
Muscarinic receptor antagonists
- Inhibit the muscarinic acetylcholine receptors of the detrusor muscles to decrease contribution of bladder over-activity to lower urinary symptoms
- Oxybutynin is used for this purpose, but is not selective
- As a consequence, constipation dry mouth, eyes are common
- Can exacerbate obstructive symptoms
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Phosphodiesterase type 5 inhibitor
- Inhibition of this PDE5, which normally breaks down cGMP, will favor ongoing cGMP signaling and relaxation (initially FDA approved for erectile dysfunction)
- Tadalafil
- May also cause headache, indigestion, flushing
- Concomitant use of α-adrenergic receptor blockers or nitrates can cause symptomatic hypotension

β3 adrenergic agonist
- Activates beta 3 receptor on detrusor muscle to facilitate filling and storage (Increase bladder capacity)
- Also raises blood pressure
- Newer drug, so side effects and long term consequences not as well understood
Storage reflex

Voiding Reflex



