Pathophysiology of Erectile Dysfunction and Benign Prostatic Hyperplasia Flashcards
What is the definition of an Erectile Dysfunction?
Inability to achieve and maintain an erection sufficient to permit satisfactory sexual intercourse
What qualifies as ED?
3 months of failing to achieve erections
What co-morbidities can cause ED?
- Obesity
- Dyslipidemia
- Metabolic Syndrome
- Tobacco Use
What is the Corpora Cavernosa?
Two cylinders of erectile tissue (top of penis)
What is the Corpus Spongiosum?
Surrounds the urethra (bottom of penis) and expands to form the glands
What NT helps blood flow into the penis via vasodilation?
ACh
What are the steps to achieve an erection?
- Bloodflow increases and fills the copra sinusoids
- Those filled corpora then compress subtunical venules to decrease outflow of blood
What are the 2 possible pathways ACh facilitates erection?
- Improves NO production
- Increases cAMP
What is the primary pathway for an erection?
NO activated cGMP = decrease Ca2+ = relaxed muscle
What is the secondary pathway for an erection?
Increase cAMP = muscle relaxation
What is the MAIN NT for erections?
NO
What metabolizes cGMP?
Phosphodiesterase type 5 aka PDE 5 in the corpora cavernosa
Where do the spinal cord cholinergic nerves connect to for sexual stimulation?
Corpora Vasculature
What is the role of NE in erections?
Vasoconstrictor, = detumescence
Does testosterone help with ED?
NO, but it does help with libido
What are the 2 physiologic functions of testosterone?
Stimulate Libido and Increase Muscle Mass
What is the normal concentration of testosterone?
300-1100 ng/dL
Is testosterone a primary mediatory of erectile dysfunction?
NO
What is Secondary ED?
Patient has hypogonadism and decreased libido
What is Organic ED?
Etiology is vascular, neurologic, and/or hormonal
Main Cause
What is Pyschogenic ED?
No organic causes and the patient does not respond to psychogenic stimuli
What is one disease that could inhibit blood flow into the corpora cavernosa? (vascular organic)
HTN, ASCVD, PVD
What is one disease that could impair spinal cord nerve conduction? (neurologic organic)
MS, Injury, Stroke, PD
What is one disease that could block peripheral nerve conduction? (neurologic organic)
DM
What are lifestyle factors that can cause ED?
Alcohol abuse, smoking, obesity, and physical inactivity
What are causes of ED associated with damage?
Old age, DM, renal failure, heart disease, HTN, ASCVD, and hypothyroidism
How can Antihypertensives cause ED? What are examples?
Reduced arterial flow into corpora
Diuretics and BB
How can Dopamine Antagonists cause ED?
Inhibit prolactin inhibitory factor, increasing prolactin levels
How can Anticholinergics cause ED? What are examples?
Anticholinergic Activity
Anti-Parkinson’s
How can Estrogen or Antiandrogenic Drugs cause ED? What are some examples?
Suppress testosterone mediated stimulation of libido
Digoxin and Spironolactone
How can CNS Depressants cause ED? What are some examples?
Suppresses psychogenic stimuli
Narcotics and Benzos
What other drugs cause ED?
Lithium
Gemfibrozil
Clofibrate
Finasteride
Dutasteride
What is Benign Prostatic Hyperplasia?
Enlargement of the prostate gland
What is the normal prostate weight?
15-20 grams
What is the anatomy of the prostate?
Small gland located below the bladder that surrounds the urethra
What is the primary function of the prostate?
To secrete fluids that make up 20-40% of the ejaculate
What are the 3 prostate tissues?
- Epithelial Glandular
- Stromal
- Capsule
What is the function of the epithelial glandular?
Produce secretions
What is the function of the stromal?
Smooth muscle with lots of ALPHA-1 RECEPTORS, activated by NE to cause smooth muscle contraction = decreases bladder emptying
What is the function of the capsule?
Connective smooth muscle with ALPHA-1 Receptors
What metabolizes testosterone?
5-alpha-reductase
What is DHT and it’s role in the prostate?
Dihydrotestosterone an active metabolite of TST, facilitates prostate growth, and much for potent in the prostate
What are the two types of Lower Urinary Tract Symptoms LUTS?
- Obstructive
- Irritative
What are the Obstructive Symptoms?
Reduction in bladder emptying (weak stream, low flow rate, incomplete/slow emptying)
Full Bladder feeling after voiding
What are the Irritative Symptoms?
Over sensation of bladder muscles from long-standing = Nocturia
Bladder cannot void = retention and UTIs
How do you know if a BPH medication is working?
If the AUA score improves by 3 points
What is the physical exam for BPH?
Digital Rectal Exam DRE
What is classified as Mild BPH?
<7
What is classified as Moderate BPH?
8-19
LUTS
What is classified as Severe BPH?
> 20
UTI, Insufficiency, Bladder stones