Management of Erectile Dysfunction by the Geriatrician
March 30, 1998
Management of Erectile Dysfunction by the Geriatrician
ABSTRACT & COMMENTARY
Synopsis: Erectile dysfunction is the most common health disorder to affect elderly men, yet it is not an inevitable consequence of healthy aging. New developments in understanding and treatment can enable primary care doctors to initiate evaluation and therapy.
Source: Godschalk MF, et al. J Am Ger Soc 1997;45:1240-1246.
This summary report urges physicians to begin the work-up for sexual complaints by distinguishing three principal components of male sexual function: libido, erectile rigidity, and orgasm. If libido is diminished, the most likely cause in elderly men is hypogonadism, and, if a serum testosterone returns with a low value, this can be treated pharmacologically.
More commonly, libido will be normal, but erectile dysfunction is present, reported in one survey as high as 67% in men at age 70.1 In normal erections, psychic or genital stimulation decreases sympathetic and increases parasympathetic neural activity, which induces penile smooth muscle relaxation through nitric oxide increasing cGMP. Penile arterial resistance then falls, with increased arterial inflow to the penis. The lacunar spaces fill with blood, which compresses subtunical venules, leading to trapped blood in the corpora cavernosa. The resulting rising pressure from increased inflow and decreased outflow leads to rigidity. The most common etiology of erectile dysfunction in aged men is vascular disease (arteriosclerosis, with increased risk from smoking, hypertension, hypercholesterolemia, and diabetes mellitus), followed by neurologic etiologies (autonomic dysfunction from stroke, Parkinson's disease, and diabetes).
The key question in evaluation of erectile dysfunction is whether the onset was gradual or sudden. For sudden onset, the etiology is either drug-induced or psychogenic, which can be distinguished by inquiring about the presence of sleep-associated erections (SAE). If SAEs are present with sudden onset of impotence, the cause is likely to be psychogenic, which may respond to reassurance or sex therapy. Without SAE, the cause is likely to be drug-induced, the common offenders being medications with anticholinergic effects (antihistamines, antidepressants, antipsychotics) or any drug that lowers blood pressure (particularly in patients with marginal blood flow to the penis).
Gradual onset of erectile dysfunction with normal libido is more likely to be caused by vascular or neurologic disease, although in older patients the cause can still be drug-induced. Physical exam should look for confirmatory signs such as absent pedal pulses, orthostatic hypotension, or absent bulbocavernosus reflex (squeezing the head of penis while watching for rectal sphincter contraction). Laboratory studies should be a lipid profile, HbA1C, and serum testosterone pooled from three early morning samples 30 minutes apart.
Finally, these authors recommend a diagnostic intracavernosal injection of vasodilator, either papaverine or prostaglandin E1 (PGE1). Erection should follow within 15 minutes; poor or absent response suggests vascular etiology, full erection suggests neurogenic etiology, and partial erection suggests a mixed etiology.
Therapy is directed at increasing penile rigidity, which can be accomplished by vacuum devices, intracavernosal injection, or transurethral PGE1. Oral medications were still being investigated at the time of this report. Vacuum devices are hollow plastic tubes that increase arterial flow into the penis by inflation with a manual or battery pump; cost is $200-500, which is allowed by Medicare Part B. The resulting erection is maintained with a constrictor ring at the base of the penis.
Self-injection has become the most commonly used treatment for erectile dysfunction, although there are risks of fibrosis and prolonged erections. The latter must be treated after more than four hours with corpora cavernosa aspiration followed by an injection of phenylephrine solution to avoid tissue hypoxia and ischemia.
Although the authors feel that urology referral is unnecessary for most patients with erectile dysfunction unless there is no response to the above treatments, they do recommend maintaining a "close relationship" with a urologist to help with the management of prolonged erections. They encourage physicians to incorporate the evaluation and treatment of erectile disorders into routine office examinations.
COMMENT BY MARY ELINA FERRIS, MD
As the baby boomer generation crosses the threshold into their 40s and 50s where the known incidence of erectile dysfunction takes a steep upward jump, they need not feel doomed by age or lack of medical therapies. Although this article promotes the use of vacuum pump devices and injection therapy, there are high dropout rates due to pain, bruising, fear of complications, and lack of spontaneity.2 One study of injection therapy following 100 men showed only 32% still using it after five years.3 A recent comparison of the two therapies for satisfaction, effectiveness, and side effects involving random assignment of 50 men showed both methods effective with similar side effects, although more satisfaction of both patient and partner was seen with injections, particularly among younger patients.4
Louis Kuritzky, MD, an associate editor of Internal Medicine Alert, would disagree with these authors and urge that it is unnecessary to include intracavernosal injection as part of the diagnostic work-up, since the same treatment options will be offered to the patient regardless of the results, and furthermore, false negative results may be seen from the stress of the visit or the injection itself, preventing the occlusive phase of the erection.5 He further argues that the therapy should be "goal-directed" to minimize testing and to proceed more quickly to restoration of sexual function. Other authors question the need for routine testosterone testing and suggest that it only be ordered in men over age 50.6
Even more hopeful for this problem is the prospect of new oral and topical medications being approved by the FDA in 1998 and 1999.7 PGE1 delivered both orally and transurethrally by suppositories instead of injections has shown promising results; a drug that dilates penile blood vessels (phentolamine) can produce erections in 34-40% of men in 20-40 minutes; a blocker of the enzyme that breaks down cGMP (sildenafil) had a response of 60-80% in the same time period; and sublingual apomorphine acts on brain functions to produce erections in 70% of men with psychogenic or minimally organic impotence. Any or all of these new treatments would be a welcome relief for physicians and patients in dealing with the problem of erectile dysfunction.
References
1. Feldman HA, et al. Impotence and its medical and psychosocial correlates: Results of the Massachusetts Male Aging Study. J Urol 1994;151:54-61.
2. Cookson MS, et al. Long-term results with vacuum constriction device. J Urol 1993;149:290-294.
3. Sundaram CP, et al. Long-term follow-up of patients receiving injection therapy for erectile dysfunction. Urology 1997;49:932-935.
4. Soderdahl DW, et al. Intracavernosal drug-induced erection therapy versus external vacuum devices in the treatment of erectile dysfunction. Br J Urol 1997;79:952-957.
5. Kuritzky L. Goal-directed therapy for erectile dysfunction (letter). Am Fam Physician 1997;56:379.
6. Buvat J, et al. Endocrine screening in 1022 men with erectile dysfunction: Clinical significance and cost-effective strategy. J Urol 1997;158:1764-1767.
7. Garcia-Reboll L, et al. Drugs for the treatment of impotence. Drugs Aging 1997;11:140-151.
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