Disorders commonly associated with erectile
dysfunction (ED) include diabetes mellitus, hypertension and spinal cord injury.
Diabetes results in ED through its vascular,
neurologic and psychogenic compli- cations, rather than through any hormonal alterations.
The prevalence of ED in diabetic men ranges from 35% to 75%, and increases with age. Tight
metabolic control from the outset of the disease is the best preventive measure.
Hypertension is a common risk factor associated with
arterial insufficiency and about 45% of men with ED have hypertension. ED in hypertensive
disease is caused by the associated arterial stenotic lesions. It may also be caused by
various drugs used to lower blood pressure including methyldopa, clonidine, reserpine,
propranolol (and other b-blockers), thiazide diuretics and spironolactone.
In men with spinal cord injury, the severity of sexual
dysfunction depends on the level and completeness of the cord lesion and the duration of
the injury. These patients experience not only sexual dysfunction and infertility, but
also psychological problems.
Peyronie’s disease is not uncommon, although its
prevalence in Asia is difficult to quantify. The condition is charaterized by the presence
of a penile plaque with curvature of the erect penis, painful coitus, and ED.
The extent of concomitant ED and the curvature and
deformity of the penis, if present, can be assessed via the use of intracavernosal
injection of alprostadil (prostaglandin E1).
Diagnosis is assisted by ultrasonography of the corpora cavernosa, magnetic resonance
imaging (for characterizing penile anatomy), and computed tomography (for differentiating
pathlogical lesions in the tunica albuginea).
Management options for Peyronie's disease are medical treatment,
surgical treat- ment and prosthesis implantation. Medical therapy options include oral
vitamin E, potassium aminobenzoate and colchicine, and intralesional collagenase or
verapamil, all of which have had some reported success.
Candidates for surgical treatment include those who are unresponsive
to medical therapy, patients with severe deformity or later-stage plaque calcification,
and those who require a more rapid solution to their condition. Surgical treatment is by
either penile curvature correction (e.g. via a modified Nesbit procedure) or prosthesis
implantation. About 10% of patients require surgery, which is mostly performed under
spinal or general anesthesia, although local anesthesia can also be used.
Penile augmentation surgery should be limited to patients whose erect
penile length falls below two standard deviations from the norm. Definite indications for
it include true micropenises, concealed or buried penis, Peyronie's disease, spinal cord
injury patients with a short penis, and traumatic amputated penis.
Where indicated, lengthening procedures and techniques to increase
penile girth (e.g. dermal fat grafts) may be undertaken. However, all patients should
undergo psychological counselling prior to surgery to minimize the problems associated
with poor satisfaction in those with dysmorphophobia.
In aging men, a progressive age-related decrease in androgen
secretion and reproductive capacity occurs in a significant number of cases. Circulating
bioavailable testosterone levels generally decrease with age because of an increase in sex
hormone-binding globulin (SHBG).
Aging men who present with climacteric symptoms such as flushing,
inability to concentrate, and impaired sexual function should therefore undergo an
endocrine workup with measurement of plasma testosterone, luteinizing hormone (LH) and
follicle-stimulating hormone (FSH).
Such men with subnormal or low-normal levels of testosterone are
candidates for testosterone supplementation, the expected benefits of which are increased
bone mineral density and bone turnover, increased muscle mass and body strength, and
possibly an improved sense of well-being, sexual function and libido.
However, these potential benefits need to be balanced against the
potential risk of adverse effects, which include acceleration of prostatic cancer, fluid
retention, aggravation of hypertension, peripheral edema, congestive heart failure, and
exacerbation of sleep apnea.
Where indicated, the three main types of androgens that may be
administered are: (1) orally active agents such as testosterone undecanoate; (2)
injectable preparations such as testosterone enanthate or cypionate or mixed testosterone
esters; and (c) transdermal testosterone delivery systems (scrotal and nonscrotal
patches). Periodic monitoring during testosterone therapy is mandatory to detect
treatment-related adverse effects as early as possible.
In Asia, it needs to be remembered that a significant number of men
with sexual dysfunction will take alternative medicines to overcome their problems (e.g.
`jamu', yohimbine, muira puama, tribulus terrestris, Korean red ginseng, and eurycoma
longifolia jack), rather than consult their family doctors. Efforts are now being made to
`westernize' the application of such alternative therapies through standardization and
clinical evaluation.
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