Sexual Dysfunction
Prior to 1980, sexual dysfunction of any cause was lumped under the term
“impotence” for men and “frigidity” for women. Since then, the classification
of sexual disorders has evolved and is now based on the physiologically
oriented, four-phase model of human sexuality (Chapter 15). This classification
divides the sexual dysfunction syndromes into disorders of desire, disorders of
excitement/arousal and disorders of orgasm. The fourth phase of the human
sexual response, resolution, is rarely disturbed. Sexual desire disorders
include hyperactive and hypoactive sexual drive (libido) and sexual aversion.
Excitement phase disorders include erectile dysfunction, dyspareunia and
vaginismus. Orgasmic disorders include inhibited orgasm in women and premature
ejaculation in men.
Sexual desire disorders
Normal sexual drive can be
thought of as a balance between an “erotic motor,” which incites a desire for
sexual activity, and a “sexual brake,” which keeps urges in check. These
excitatory and inhibitory signals appear to converge upon specific centers in
the hypothalamus and limbic system to produce a continuum of sexual desire. It
is probably only the polar ends of this range that are abnormal (Fig. 33.1).
There is no specific test for abnormal sexual desire. Instead, the diagnosis of
a sexual desire disorder is based on the subjective reporting of abnormal
libido that results in individual distress or interpersonal difficulty.
The two formally recognized
sexual desire disorders are hypoactive sexual desire disorder (HSDD) and sexual
aversion disorder. HSDD is defined as persistently or recurrently deficient (or
absent) sexual fantasies or desire for sexual activity. Sexual aversion
disorder is the persistent or recurrent extreme aversion to, and avoidance of,
all (or almost all) genital sexual contact with a sexual partner. Of patients seeking treatment for sexual desire
disorders, 79% have HSDD, 20% have sexual aversion disorder and 1% have
hyperactive sexual desires. The causes of sexual desire disorders may be either
organic or psychosocial. Organic causes include testosterone deficiency,
chronic illness, certain centrally acting medications and underlying
psychiatric disturbances. Psychogenic causes involve psychologically repressive
stimuli such as anxiety, anger, perception of a partner as repulsive, or
previous negative sexual experiences.
Treatment of the sexual desire
disorders is directed first toward evaluation and correction of any underlying
organic problem. Psycho- therapy may be useful in the treatment of sexual desire
disorders of nonorganic etiologies. Patients with long-standing sexual
dysfunction of organic etiology often develop concomitant psychosocial issues.
Individual or group counseling may be extremely useful as adjunctive therapy in
these patients.
Erectile dysfunction (impotence)
Erectile dysfunction (ED) is the
recurrent inability of a man to get and keep an erection sufficient for
intercourse. ED is mild if a man can usually get and keep an erection, moderate
if he can only can get or keep an erection sometimes and complete if he never
can. Risk factors for ED include aging, chronic illnesses, a variety of
medications and cigarette smoking. It is a common problem among older men; estimates
report that 50% of 40- to 70-year-old men have some degree of ED. Even more are
affected after the age of 70.
ED can occur because of
vasculogenic, neurogenic, hormonal or psychogenic problems. Eighty per cent of
the diagnosable conditions leading to ED are organic. They include, in
decreasing order of frequency, atherosclerosis, diabetes, hypertension,
medication side effects, prostate surgery, hyperthyroidism
and hypothyroidism, hyperprolactinemia and hypogonadism. While depression is
present in 60% of men with ED, it is often unclear whether this mood disorder
is the cause or the result of long-standing ED.
Successful penile erection
involves the activity of autonomic nerves upon the vascular smooth muscle of
the penis. Relaxation of penile vascular smooth muscle allows blood to flow
into the penis. Here it remains trapped and erection occurs (Chapter 13). Most
of the organic causes of ED involve neuropathies of the autonomic nervous
system, vascular compromise or, occasionally, testosterone deficiency. Psychogenic
ED involves abnormal central inhibition of the erectile mechanism in the
absence of demonstrable physical abnormality. The presence of morning erections
in a man with ED may suggest a psychogenic etiology. Drugs that produce ED are
myriad and typically affect the neural reflex pathways necessary for
integrating the erection. Examples of medications associated with ED include
antidepressants, antipsychotics, sedatives, antianxiety medications,
antihypertensives and anticonvulsants. Alcohol and street drugs, including
amphetamines, cocaine, marijuana, methadone and heroin, can also cause ED.
Until recently, treatment options for ED were limited to medication changes,
implantable erection devices, intracavernosal injections of prostaglandins and
psychotherapy. The discovery that the drug sildenafil can facilitate and
maintain erections in impotent men has changed the treatment of ED
dramatically. Sildenafil was originally tried as an antiangina medication and
found to be ineffective. The study subjects were reluctant to turn in their
leftover pills and soon the drug’s unexpected side effect was uncovered. Since
then sildenafil, and related drugs, have been shown to be effective in the
treatment of ED and have become widely available for this use. These
medications work by inhibiting phosphodiesterase type V (PDE5), a cyclic
guanosine monophosphate (cGMP) metabolizing enzyme found predominantly in the
penis. Nitric oxide (NO) activates guanylate cyclase in the penis, increasing
cGMP, the major mediator of the vascular relaxation necessary for penile
erection. The longer cGMP stays around, the longer the duration of erection.
Blockade of cGMP metabolism promotes and maintains NO proerectile activity.
PDE5 inhibitors will not cause erections in the absence of sexual stimuli.
Premature ejaculation
This is a disorder characterized
by ejaculation that occurs with minimal sexual stimulation after penetration
and before the man wishes it. This must occur on multiple occasions over time
to warrant diagnosis. When making the diagnosis, the man’s age, the novelty of
the sexual partner and circumstances and his frequency of sexual activity must
be taken into account. Premature ejaculation is reported by 10–35% of men
seeking help for sexual dysfunction. Unlike ED, which increases with age, premature
ejaculation decreases with age.
The exact cause of premature
ejaculation is unknown. The only demonstrable physiologic correlate of
premature ejaculation is that men reporting this disorder ejaculate at a lower
level of sexual arousal than do control men.
Retrograde ejaculation
In men with retrograde
ejaculation, semen travels backwards into the bladder rather than out of the
penile shaft during ejaculation because the bladder neck does not close
appropriately during or after emission. The most common cause of retrograde
ejaculation is inability of the bladder neck to close following transurethral
prostatectomy (TURP). Damage to penile innervation during prostate surgery,
diabetic neuropathy and the use of anticholinergic medications are neurologic
causes of the condition. Retrograde ejaculation does not require intervention
unless fertility is desired (Chapter 34).
Dyspareunia
Patients with dyspareunia
experience recurrent or persistent genital pain before, during (the most
common) or after sexual intercourse. Of women seeking help with sexual
problems, 10–30% report dyspareunia, while only 1% of men report the problem.
Because dyspareunia is reported far more frequently in women than in men, much
more is known about its etiologies and interventional approaches in women.
Dyspareunia may reflect a
physical or psychogenic problem. Details of whether the symptoms are lifelong
or acquired, generalized or situational are helpful in identifying the
potential etiology. Organic causes of dyspareunia include the presence of
hymeneal remnants, pelvic tumors, endometriosis, pelvic inflammatory disease
and vulvar vestibulitis. Hypoestrogenic states associated with menopause, the
early postpartum period, use of very low dose oral contraceptives and prior
treatment with chemotherapy may also cause dyspareunia. Psychosocial problems
that result in dyspareunia may include poor self-esteem and body image, guilt
and prior sexual abuse or trauma. Interpersonal factors between the couple,
including anger, distrust and poor com- munication, may also be responsible.
Treatment of dyspareunia is
directed toward evaluation and correction of underlying organic problems.
Psychotherapy may be useful in the treatment of dyspareunia of nonorganic
causes. It may also be useful as concomitant therapy for those with primary
organic causes.
Vaginismus
Women with vaginismus experience
recurrent involuntary spasms of the pelvic muscles of the outer third of the
vaginal barrel of such severity that intercourse is painful or impossible.
Typically, these occur in anticipation of intercourse or during penetration. In
some women with severe vaginismus, spasms can also occur during a pelvic
examination or tampon insertion.
Vaginismus occurs in 0.5–5% of women.
There are significant intercultural differences. Lifelong vaginismus is a rare
clinical entity in North America and most of Western Europe. It is relatively
common in Ireland, Eastern Europe and Latin America. It is the most commonly
reported cause of unconsummated marriages.
Like dyspareunia, vaginismus can
have either an organic or psycho- social etiology. The organic bases of the
disorder are the same as those of dyspareunia. In fact, most experts believe
that vaginismus begins as dyspareunia and escalates to vaginismus through a classic
conditioning process. In this view, a woman first has pain on intercourse
(unconditioned stimulus) and this leads to a natural self-protecting tightening
of the vaginal muscles (conditioned response). Over time, stimuli associated
with vaginal penetration can become conditioned stimuli and provoke the
conditioned reflex muscle spasms. In severe cases, conditioned stimuli can even
include thoughts of sexual intercourse.
Not all cases of vaginismus are
classically conditioned from an organic cause. Many psychosocial contributors
have been suggested, including guilt, religious constraints, responses to a
partner’s sexual dysfunction, prior sexual trauma, concerns about sexual
orientation and fears of pregnancy, sexually transmitted diseases and trauma.
Like dyspareunia, treatment of
vaginismus is directed toward evaluation and correction of any underlying
organic problem, and psychotherapy.
