Erectile Dysfunction

Erectile Dysfunction

Erectile DysfunctionGretchen  M.  Irwin,MD,  MBAINTRODUCTIONErectile dysfunction is defined by the Fourth International Consultation on SexualMedicine as the consistent or recurrent inability to attain and/or maintain penile erec-tion sufficient for sexual satisfaction.1Erectile dysfunction is a common condition,affecting up to 30 million men in the United States.2Physicians should ask male pa-tients about sexual health to identify men affected by erectile dysfunction, to identifypotentially life-threatening underlying conditions associated with erectile dysfunction,and to improve overall quality of life for the patients. 

PATHOPHYSIOLOGY AND RISK FACTORSErectile 

function is dependent on a complex interaction of vascular and neuralprocesses. The internal pudendal artery supplies the majority of the blood flow tothe penis through the cavernosal branches whereas venous outflow occurs througha network of easily compressible venules. When arousal occurs, parasympathetic ac-tivity from the sacral segments of the spinal cord initiates a cascade of events torelease nitric oxide and increase intracellular cyclic guanosine monophosphate. Cyclicguanosine monophosphate increases result in vascular smooth muscle relaxation andan increase in blood flow into the corpora cavernosa. This rapid inflow of blood leadsto compression of the venule network to decrease venous outflow, thereby raisingintracavernosal pressure and resulting in erection. Erectile dysfunction, therefore,can result from any process that impairs either the neural or vascular pathways thatcontribute to erection.Because aging is an independent risk factor for the development of erectiledysfunction, many men assume that sexual impairment is an inevitable consequenceof growing older.3–5Up to one-third of 70 year old men, however, in a recent study re-ported no erectile difficulty.6Thus, a physician should still perform a thorough historyand physical examination to rule out other causes before assuming that new-onseterectile dysfunction is solely the result of advancing age.Risk factors for developing erectile dysfunction include tobacco use, obesity,sedentary lifestyle, and chronic alcohol use.3–5Such risk factors are believed to causehormonal changes that result in low testosterone and impaired endothelial function,which contribute to the development of erectile dysfunction. Both hypothyroidismand hyperthyroidism also may result in significant hormonal derangements that canresult in the development of erectile dysfunction.7Patients who have previously been diagnosed with diabetes mellitus, hypertension,dyslipidemia, or depression also have a higher risk of developing erectile dysfunc-tion.3–5Of men diagnosed with erectile dysfunction, approximately 40% have hyper-tension, 42% have hyperlipidemia, and 20% have diabete
 
DIAGNOSISA 
diagnosis of erectile dysfunction can be readily made by a primary care physician. Apatient is unlikely to spontaneously self-report erectile dysfunction, however. Rather, aphysician should inquire about erectile dysfunction symptoms in at-risk patients.16Once a patient has reported erectile dysfunction symptoms, a physician must take acareful history to determine the extent of symptoms as well as the contribution tosymptoms by associated chronic diseases, medication use, or psychosocial issues.Onset of symptoms, severity, degree of impact on daily life, and situational factorsthat exacerbate symptoms are critical issues to discuss with patients. Many physi-cians prefer the use of validated questionnaires to help both diagnose and track treat-ment effectiveness for patients with erectile dysfunction. Examples of validatedIrwin2
questionnaires that may be used include the Erection Hardness Score, Sexual HealthInventory for Men, and International Index of Erectile Function.17,18Furthermore, aphysician should discuss psychosocial issues with patients, such as current relation-ship dynamics, individual views of sexuality and sexual function, and current lifestressors.19In addition to thorough sexual, past medical, past surgical, medication, and psycho-social histories, a diagnosis of erectile dysfunction requires an appropriate physicalexamination. A physician should assess pulse, blood pressure, and weight giventhe association of erectile dysfunction with obesity and hypertension. Patients alsoshould be assessed for signs consistent with testosterone deficiency because lowtestosterone can contribute to erectile dysfunction and may alter treatment recom-mendations. Several studies have shown a link between erectile dysfunction and oste-oporosis.20,21In 1 study, men with erectile dysfunction were noted to have a 3-foldincrease in incidence of osteoporosis compared with men without erectile dysfunc-tion, independent of other risk factors, such as diabetes or hypertension.21It isbelieved that low androgens, high inflammation causing endothelial dysfunction,and/or reduced nitric oxide activity may play a role in increased bone reabsorption.21Physicians counsel patients about the importance of maintaining good bone health.20Laboratory studies are not required to diagnose erectile dysfunction, but, given the as-sociation with chronic disease, men with newly diagnosed erectile dysfunction shouldhave a hemoglobin A1cand lipid panel evaluated. Young men who develop erectiledysfunction should be screened for coronary vascular disease because these menmay have up to a 50% increase in risk of future cardiac events.22A morning testos-terone should be obtained, because a result less than 300 mg/dL in the setting oftestosterone deficiency symptoms warrants treatment of low testosterone as wellas erectile dysfunction. Treating both conditions may have an additive benefit for pa-tients. Emerging evidence suggests that mean platelet volume and platelet distributionwidth may be elevated in men with diabetes at risk of erectile dysfunction, althoughroutine ordering of platelet studies currently is not recommended 

TREATMENT
Multiple treatment modalities exist for erectile dysfunction. Although patients oftenstart with oral medication therapy, other options, such as a surgically implanted penileprosthesis or intraurethral and intracavernosal therapies, should be discussed withpatients at the outset. Patient preferences after a discussion of risks and benefitsshould guide treatment. Ultimately, the goal of treatment should be to improve patientquality of life by restoring sexual function when possible and improving overall healthby mitigating risk factors for cardiac and metabolic disease.Lifestyle changes should be recommended to all patients. Improved diet to facilitatelower blood pressure and weight loss, increased physical activity, and elimination oftobacco use can improve effectiveness of treatment while decreasing risk of concom-itant chronic disease. Treatment of chronic diseases, such as diabetes, hypertension,hyperlipidemia, hypothyroidism, depression, and low testosterone, can improveerectile dysfunction symptoms as well as improve effectiveness of oral medicationtreatment of erectile dysfunction.7Improved blood pressure control has been demon-strated to improve erectile dysfunction symptoms as well as decrease men’s risk ofacquiring erectile dysfunction.24The impact of treatment of metabolic disease shouldnot be underestimated because treatment with 40 mg of simvastatin for 6 monthssignificantly improved sexual health related quality of life for men over age 40 yearswith untreated erectile dysfunctio

EFERENCES1.

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