Erectile Dysfunction

There are 2 types of erectile dysfunction (ED):

• Primary ED, the man has never been able to attain or sustain an erection

• Secondary ED, acquired later in life by a man who previously was able to attain erections

Primary ED is rare and is almost always due to psychologic factors or clinically obvious anatomic abnormalities.

Secondary ED is more common, and > 90% of cases have an organic etiology. Many men with secondary ED develop reactive psychologic difficulties that compound the problem.

Psychologic factors, whether primary or reactive, must be considered in every case of ED. Psychologic causes of primary ED include guilt, fear of intimacy, depression, or anxiety. In secondary ED, causes may relate to performance anxiety, stress, or depression. Psychogenic ED may be situational, involving a particular place, time, or partner.

The major organic causes of ED are physiologic (organic)

• Vascular disorders

• Neurologic disorders

These disorders often stem from atherosclerosis or diabetes.

The most common vascular cause is atherosclerosis of cavernous arteries of the penis, often caused by smoking, endothelial dysfunction, and diabetes. Atherosclerosis and aging decrease the capacity for dilation of arterial blood vessels and smooth muscle relaxation, limiting the amount of blood that can enter the penis (see Overview of Male Sexual Function: Erection). Endothelial dysfunction is a disease of the endothelial lining of the small arterioles that reduces the ability to vasodilate when needed to increase blood flow. Endothelial dysfunction appears to be mediated by reduced levels of nitric oxide and can result from smoking, diabetes, and/or low testosterone levels. Veno-occlusive dysfunction permits venous leakage, which results in inability to maintain erection.

Priapism

Neurologic causes include stroke, partial complex seizures, multiple sclerosis, peripheral and autonomic neuropathies, and spinal cord injuries. Diabetic neuropathy and surgical injury are particularly common causes.

Complications of pelvic surgery (eg, radical prostatectomy [even with nerve-sparing techniques], radical cystectomy, rectal cancer surgery) are other common causes. Occasionally, transurethral resection of the prostate is a cause. Other causes include hormonal disorders, drugs, pelvic radiation, and structural disorders of the penis (eg, Peyronie disease). Prolonged perineal pressure (as occurs during bicycle riding) or pelvic or perineal trauma can cause ED.

Any endocrinopathy or aging with testosterone deficiency (hypogonadism) may decrease libido and cause ED. However, erectile function only rarely improves with normalization of serum testosterone levels because most affected men also have neurovascular causes of ED.

Numerous drug causes are possible (see table Commonly Used Drugs That Can Cause Erectile Dysfunction). Alcohol can cause temporary ED.

• Clinical evaluation

• Screening for depression

• Testosterone level

Evaluation should include history of drug (including prescription drugs and herbal products) and alcohol use, pelvic surgery and trauma, smoking, diabetes, hypertension, and atherosclerosis and symptoms of vascular, hormonal, neurologic, and psychologic disorders. Satisfaction with sexual relationships should be explored, including evaluation of partner interaction and partner sexual dysfunction (eg, vulvovaginal atrophy, dyspareunia, depression).

It is vital to screen for depression, which may not always be apparent. The Beck Depression Scale or, in older men, the Yesavage Geriatric Depression Scale (see table Geriatric Depression Scale (Short Form)) is easy to administer and may be useful.

Examination is focused on the genitals and extragenital signs of hormonal, neurologic, and vascular disorders. Genitals are examined for anomalies, signs of hypogonadism, and fibrous bands or plaques (Peyronie disease). Poor rectal tone, decreased perineal sensation, or abnormal bulbocavernosus reflexes may indicate neurologic dysfunction. Diminished peripheral pulses suggest vascular dysfunction.

A psychologic cause should be suspected in young healthy men with abrupt onset of erectile dysfunction (ED), particularly if onset is associated with a specific emotional event or if the dysfunction occurs only in certain settings. A history of ED with spontaneous improvement also suggests psychologic origin (psychogenic ED). Men with psychogenic ED usually have normal nocturnal erections and erections upon awakening, whereas men with organic ED often do not.

• Treatment of underlying causes

• Drugs, usually oral phosphodiesterase inhibitors (see table Oral Phosphodiesterase Type 5 Inhibitors for Erectile Dysfunction)

• Vacuum erection device or self-administered intracavernosal or intraurethral prostaglandin E1 (2nd-line treatment)

• If other treatments fail, surgical implantation of penile prosthesis

Underlying organic disorders (eg, diabetes, prolactin-secreting pituitary adenoma, hypogonadism, Peyronie disease) require appropriate treatment. Drugs that are temporally related to onset of erectile dysfunction (ED) should be stopped or replaced. Depression may require treatment. For all patients, reassurance and education (including of the patient’s partner whenever possible) are important. Clinicians should use this encounter to discuss behavior modification (eg, dietary changes and weight loss).

For further therapy, an oral phosphodiesterase inhibitor is tried first. If necessary, another noninvasive method, such as a vacuum erection device or intracavernosal or intraurethral (suppository) prostaglandin E1 is tried next. Invasive treatments are used when noninvasive methods fail. All drugs and devices should be tried ≥ 5 times before being considered ineffective. For cases of mild erectile dysfunction, low-intensity shockwave therapy (Li-SWT) is an emerging technique that awaits approval by the U.S. Food and Drug Administration (FDA). Theoretically, it works by limiting fibrosis in the corporal bodies.