Erectile dysfunction can be caused by any number of medical and psychological conditions. In general, ED is divided into organic (having to do with a bodily organ or organ system) and psychogenic (mental) impotence. Interestingly, and not surprisingly, most men with organic causes have a mental or psychological component, as well.
Male erectile problems often produce a significant emotional reaction based on the impact of erectile dysfunction on confidence, self-esteem, and morale in most men. This is described as a pattern of anxiety and stress that can further interfere with normal sexual function. Such "performance anxiety" needs to be recognized and addressed by a doctor.
The ability to achieve and sustain erections requires the following:
- A healthy nervous system that conducts nerve impulses from the brain, spinal column, and the penis
- Healthy arteries in and near the corpora cavernosa of the penis so that when stimulated there is an increase in blood flow to the penis
- Healthy smooth muscle and fibrous tissue within the corpora cavernosa so that it can fill with blood
- An adequate amount of nitric oxide (NO) in the penis to help with the stimulation of blood flow into the penis
- Normal functioning of the tunica albuginea, the layer of tissue surrounding the corpora cavernosa and responsible for the compression of the veins to keep blood in the penis
- Appropriate psychosocial interactions to enhance sexual stimulation/arousal and decrease anxiety/stress
Erectile dysfunction can occur if any of these requirements are damaged. The following are causes of erectile dysfunction in men, and many men may have more than one cause.
- Arterial vascular diseases account for nearly half of all cases of ED in men older than 50 years of age. Arterial vascular disease includes atherosclerosis (fatty deposits on the walls of arteries, also called hardening of the arteries), which may affect the heart (history of heart attacks, angina, coronary artery disease, myocardial infarct) or blood vessels in the legs, peripheral vascular disease (problems with blood circulation to the legs), as well as other areas of the body including blood vessels supplying blood to the penis and high blood pressure. Prolonged tobacco use (smoking) is considered an important risk factor for ED because it is associated with poor circulation and reduced blood flow in the penis. This is related to microvascular damage (stiffening of the artery as well as smaller caliber vessel size secondary to endovascular atherosclerotic plaques).
- The presence of ED is correlated to the presence of cardiac disease. In some studies, the onset of ED can precede a heart attack by five to seven years. As such, particularly for younger men with acute onset of ED, cardiovascular investigation may also be suggested.
- Chronic medical conditions have been associated with ED. Systemic diseases associated with ED include the following:
- Hypertension can worsen atherosclerosis.
- The treatment of hypertension can cause dysfunction (most commonly, treatment with beta-blocker medications and thiazide diuretics, which have the biggest implication on ED).
- Diabetes can cause erectile dysfunction by affecting the arteries, nerves, and tissue in the corpora cavernosa.
- Enlarged prostate (benign prostatic hyperplasia, or BPH): There is a class of medications called 5ARI (5-alpha-reductase) that have a notable impact on both libido and erectile dysfunction in men. Finasteride (Proscar) and dutasteride (Avodart) are in this drug class.
- Psychiatric disorders (anxiety, depression, psychosis)
- Renal (kidney) failure
- Liver cirrhosis
- Hemochromatosis (too much iron in the blood)
- Cancer and cancer treatment (related to its surgery, radiotherapy, or chemotherapy, which all affect peripheral nerves and small blood vessels)
- Hypertension can worsen atherosclerosis.
- Respiratory disease associated with ED: chronic obstructive pulmonary disease
- Endocrine conditions associated with ED
- Hypogonadism (low testosterone levels, also known as andropause): It appears that adequate levels of testosterone are needed to maintain nitric oxide levels in the penis.
- Abnormalities of the pituitary gland, prolactinoma, can cause hormonal issues that may affect erectile function.
- Psychological conditions associated with ED
- Widower syndrome
- Performance anxiety
- Nutritional states associated with ED
- Zinc deficiency
- Blood diseases associated with ED
- Sickle cell anemia
- Trauma to the pelvic blood vessels and nerves is another potential factor in the development of ED. Bicycle riding for long periods has been implicated, so some of the newer bicycle seats have been designed to soften pressure on the perineum (the soft area between the anus and the scrotum). Certainly, history of pelvic bone fracture, as well as previous pelvic surgery (orthopedic, vascular, colon-rectum, and prostate) may result in injury to the arteries or nerves that go to the penis.
- Surgical procedures associated with ED include the following:
- Procedures on the brain and spinal cord
- Retroperitoneal or pelvic lymph node dissection
- Aortoiliac or aortofemoral bypass
- Abdominal perineal resection
- Radical prostatectomy for prostate cancer
- Transurethral resection of the prostate for BPH (enlarged prostate)
- Cryosurgery of the prostate
- Radical cystectomy for bladder cancer
- Peyronie's disease is a condition that is thought to occur due to minor trauma to the penis that results in injury to the tunica albuginea and scarring; Peyronie's may cause erectile dysfunction due to lack of compression of the veins by the scarred tunica. The penile curvature that develops due to this scarring may make penetration difficult or impossible.
- Priapism, an erection lasting longer than four to six hours, can be associated with subsequent troubles achieving an adequate erection, and the treatment of long-standing priapism may also cause erectile dysfunction.
- Medications used to treat other medical disorders may cause ED. Common medications associated with ED include the following:
- Antihypertensives (for high blood pressure)
- Antiulcer drugs such as cimetidine (Tagamet)
- Hormonal medication, such as goserelin (Zoladex), leuprorelin (Lupron), finasteride (Proscar), or dutasteride (Avodart)
- Drugs that lower cholesterol
- Substance abuse: Marijuana, cocaine, heroin, methamphetamines, crystal meth, and narcotic and alcohol abuse can contribute to erectile dysfunction. Alcohol abuse can also affect the testicles and lower testosterone levels.
- Nervous system disorders associated with ED include the following:
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