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Sexual Dysfunction


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.