Male Sexual Dysfunction
Normal Sexual Response
components of normal response:
Excitement Phase: Cardiovascular changes, tachycardia, Ý BP, Hyper Ventilation, Testicular accent, erection of nipples
Aspects of Sexual Response:
- Neurogenic: nerves must be intact to deliver appropriate stimulation; cognition also plays a role in sexual arousal
- Hormonal: Testosterone is important, as is an intact Hypothalamic/pituitary axis
- Psychogenic: emotional factors and stress can affect impotence
- Vasculature: plays a critical role in erectile function
Ascending stimulation to T12 dorsal nerve results in descending stimulation that contracts prostatic, seminal vesicle muscles, etc.
Normal part of sexual response
Organism: CNS phenomena. Possible without errection or ejaculation
- Penile erection:
- Medial pre-optic area: psychogenic erection generated here and is possible even in spinal injury
- Reflexogenic erection: tactile reflex through a sacral arch makes erection possible in spite of upper spinal injury
Pathology of Ejaculation
Premature Ejaculation: most common male sexual dysfunction.
Delayed Ejaculation: associated with diabetes
Retrograde Ejaculation: musculature of the bladder neck normally constricts during ejaculation to prevent back flow into the bladder.
- Defined as ejaculation prior to or 1 minute after vaginal penetration.
- Treated with Seratonin re-uptake inhibitors (anti-depressants) clomipramine, prozac, zoloft
- The external eurethral sphincter complements the action of the bladder neck by preventing antegrade flow of semen prior to ejaculation.
- Dysfunction of this system can result in semen entering the bladder during ejaculation.
- Dysfunction can result from damage to the sympathetic fibers of the bladder neck
- semen comes out during next urination
- a agonist can be used to over come neurologic dysfunction
- infertility caused by acidic urine
- sodium bicarb can be used to neutralized urine and keep sperm viable
- Sperm can then be recovered for artificial insemination
the inability to maintain or develop an erection long enough to complete satisfying intercourse
50% of men between the ages of 40 and 70.
Caused by surgery, vascular interruptions, neurological disorders, psychogenic, etc.
Evaluation and Diagnosis:
Sexual History: acute onset vs. slow onset
Morning erection: if present think Psychogenic- hardware is working
Stimulation or partner related (not getting turned on)
Vascular risk factors
Physical examination: squeeze glans penis, if rectum tightens nerve reflex intact
Psychosocial; Basic Laboratory studies, Diagnostic tests if indicated: Vascular problems
Treatment: Injections Vacuum pump, penile prosthesis, hormones- T patches, MUSE, Oral pills (Viagra), topicals-prostaglandin/nitroglycerin
How Viagra Works:
Neuron carry NO (parasympathetic) to the Cavernosal Smooth Muscle
L-arg is converted to NO and citruline by eNOS (endothelial Nitrous Oxide Synthase).
NO stimulates cGMP production which triggers a cascade leading to smooth muscle relaxation
Relaxed muscle tone results in increased blood flow, allowing filling of the Cavernosa to the limits of the tunica albiginia.
viagra inhibits phosphodiesterase (specifically PDE-6) allowing more prolonged action of cGMP
other cGMP phosphodiesterases are affected as well:
- heart vessels – hence cannot use with nitroglycerine
- in the eye – viagra causes blue-green colorblindness, so cannot be used by pilots (blue and green lights are used to differentiate runways for takeoff and landing
prolonged erection. If painful: Venooclussion (sickle cell, crack)Þ emergency;
Painless=High flow a-v shunt often due to trauma, Surgical repair often restores normal function