Week 4: Erectile Dysfunction

Question 1

neuro/chemical mediators of erection

Answer 1

• flaccid state: penis under venous O2 tension and pressure
• vasodilation is mediated by NO and cGMP following activation of cholinergic and nonadrengeric-noncholinergic fibers.
• Prostaglandin E1: relaxes corpus cavernosum
• arterial inflow blocks venous outflow to maintain erection

Question 2

Erectile dysfunction causes

Answer 2

• can be organic, psychogenic, mixed
• can be associated with the medical conditions: aging, HTN, DM, benign prostatic hypertrophy, CV disease, smoking, depression, alcoholism, regional trauma or surgery, chronic neurologic disease, endocrinopathy, drugs
• anything that leads to small vessel disease
• Peyronie’s disease: fibrous plaques in connective tissue

Question 3

describe normal erection and how dysfunction of these steps can lead to impotence

Answer 3

1. Desire
   - problems: loss of hormones (meds, surgery, organic conditions), life stresses
2. Coordination: brain/spinal cord
   - brain tumor, stroke, parkinson’s, trauma, back injuries, MS, meds
   - can have erection reflex but can’t maintain it
3. Signal: nerves
   - pelvic surgery, DM, smoking
4. Erection: blood flow
   - atherosclerosis, HTN (meds), DM, smoking, heart disease
   - these cause arterial stenosis or impaired vasodilation leading to arterial insufficiency. Impaired relaxation of veins or SM atrophy of veins can cause excessive outflow

Question 4

Evaluation of patient with erectile dysfunction: H &P

Answer 4

1. History
   - medical and sexual history, drugs, medications
2. Physical exam
   - secondary male sex characteristics
   - femoral and lower extremity pulses
   - focused neuro exam: perianal sensation, sphincter tone, bulbocavernosus reflex (should see contraction of pelvic floor if squeeze glands penis or move catheter)
   - digital rectal exam to eval. prostate
   - detection of peyronie’s plaques (may have curvature of penis)

Question 5

evaluation of patient with erectile dysfunctions: lab tests

Answer 5

• morning serum testosterone- but if libido intact, prob. not helpful
• serum prolactin
• test for other systemic diseases: CBC, urinalysis, serum creatinine, glucose, lipid profile, thyroid function tests

Question 6

Treatment options for ED

Answer 6

1. psychosexual counseling
2. hormonal replacement
   - low prevalence of men with hypogonadism. Exogenous testosterone has low success rates and side effects
3. oral medications
   - viagra, levitra, cialis, avanafil. PDE-5 inhibitors.
   - prevents cGMP from being broken down by PDE. Still needs stimulation.
   - sildenafil and vardenafil best on empty stomach. Cialis has longer onset and halflife.
   - adverse: facial flushing, headache, muscle/backpain, nasopharyngitis
4. vacuum pumps and constriction devices
5. Injectable medications: PGE1
   - pain and priapism
6. vascular surgery
7. penile implants -last resort