Male Sexual Dysfunction

Normal Sexual Response

components of normal 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

Excitement Phase: Cardiovascular changes, tachycardia, Ý BP, Hyper Ventilation, Testicular accent, erection of nipples

Aspects of Sexual Response:

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

Ejaculation:

Ascending stimulation to T12 dorsal nerve results in descending stimulation that contracts prostatic, seminal vesicle muscles, etc.
Normal part of sexual response

Pathology of Ejaculation

Premature Ejaculation: most common male sexual dysfunction.

Defined as ejaculation prior to or 1 minute after vaginal penetration.
Treated with Seratonin re-uptake inhibitors (anti-depressants) clomipramine, prozac, zoloft

Delayed Ejaculation: associated with diabetes

Retrograde Ejaculation: musculature of the bladder neck normally constricts during ejaculation to prevent back flow into the bladder.

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

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

Erectile Dysfunction

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
Diabetes
HTN
Cholesterolemia
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

Priapism

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