Erectile dysfunction Flashcards
5 phases of an erection (0-5):
0 - flaccid phase 1 - latent (filling) phase 2 - tumescent phase 3 - full erection phase 4 - rigid erection phase 5 - detumescence phase
mechanism of erection
cavernous artery dilates = muscle contracts
causes of impotence
organic: vascular/arterial, neurogenic, anatomical, secondary to surgery
psychogenic: situational, general
drugs and substance use: alcohol, hypnotics, diuretics, alpha and beta blockers, SSRIs
riding bikes
possible referrals for impotence
mental health services
cardiology
urology
endocrinology
lifestyle changes to treat ED
weight loss regular exercise - avoid long-distance bike rides healthy diet moderate alcohol consumption smoking cessation
3 treatment options for ED
Lifestyle changes
implants/ prosthesis surgery
medication
Medication options for ED
PDE5 - 1st line (sildenafil, tadalafil, vardenafil)
prostaglandin (PG) injection - 2nd line (alprostadil)
Physiology of erection
- Pudendal nerve activates nitric oxide
- This activates guanylate cyclase (converts GTP to cGMP)
- cGPM activates protein kinase G (PKG)
- PKG decreases intracellular Ca2+
- Low Ca2+ decreases smooth muscle tone and vasodilation of penile arteries = erection
a. Adenylate cyclase converts ATP to cAMP
b. cAMP activates protein kinase A (PKA)
- PKA acts same as PKG in above process
PDE converts cGMP to GTP and cAMP to ATP