Erectile Dysfunction

What is Erectile Dysfunction? 

Erectile dysfunction (ED) can be classified as organic, psychogenic or mixed. Organic ED is due to physical defects and can be further sub-classified. Psychogenic ED is secondary to psychological factors that are thought to inhibit a man's ability to achieve an erection because of specific stressors. ED often has a mixed component of both organic and psychogenic etiologies. 

How Common is Erectile Dysfunction? 

ED is a common concern for men and their partners, can cause significant depression and anxiety and can greatly impact quality of life. ED can also lead to a lower level of physical and emotional intimacy resulting in a lower level of satisfaction within a relationship.Data from various studies has estimated that roughly half of men aged 40-70 years old have some form of erectile dysfunction. It is further estimated that 10% of men aged 30-39 have erectile dysfunction, with prevalence increasing to 59% of men aged 70-79. This extrapolates to over twenty million men in the United States alone with ED. 

How Do Erections Work? What Causes Erectile Dysfunction? 

An understanding of the basic physiology of erections (how erections work) will allow understanding of the causes and treatments of ED. The penis is an organ with paired erection chambers (corpora cavernosa), which are filled with spongy erectile tissue (corporal sinusoids) composed predominantly of smooth muscle. Erection and loss of erection are related primarily to blood flow events regulated by the penile arteries and the erectile bodies. Penile erections are triggered by one of two main mechanisms: direct stimulation of the genitalia or through stimuli coming from the brain (fantasy, smell, sound, etc). Upon stimulation, chemicals are released in the brain that cause signals to pass down the spinal cord and outward through special nerves (nervi erigentes) into the penis. These nerves release another chemical (Nitric Oxide) that causes the aforementioned smooth muscle to relax and blood rushes into the erectile bodies, causing erection. Anxiety or fear can prevent the brain signals from reaching the level required to induce erection. Medical conditions can block the erection arteries or cause scarring of the spongy erection tissue, thereby preventing proper blood flow, or trapping of blood, and limiting the erection. 

Risks & Causes 

In a process as complex as penile erections, problems can occur for many reasons. Very often an erectile problem will have more than one cause. The causes may be physical (organic ED), psychological (psychogenic ED), or a combination of both. Distinguishing between physical and psychological causes is helpful, because treatments may differ depending on the cause. 

Organic Erectile Dysfunction 

The most common cause of organic erectile dysfunction is vascular (blood vessel) disease. Vascular diseases may cause problems with blood flow into the penis to make it erect or problems with trapping of blood within the penis to maintain the erection. Atherosclerosis (buildup of plaque within the walls of arteries) is the cause of approximately 40% of erectile dysfunction in men older than 50. Among the most commonly recognized conditions associated with atherosclerosis are high blood pressure, lipid problems (cholesterol, triglycerides), diabetes and cigarette smoking.  

Diseases that affect the nervous system, such as multiple sclerosis, Parkinson's disease and Alzheimer's disease, can also cause erectile dysfunction. Some diseases associated with erectile dysfunction affect both the vascular and nervous systems. Diabetes is an example. In patients with diabetes mellitus, irrespective of type, the prevalence of erectile dysfunction is approximately 50% (range 20 to 75%) with the prevalence dependent on patient age, duration of diabetes and severity of the diabetes. 

Endocrine disorders, such as low testosterone and thyroid problems, may be associated with ED. These disorders can also affect sexual desire and cause various other symptoms. 

Erectile dysfunction can result from pelvic fractures or crush injuries experienced in an automobile, motorcycle or other accident. The accident victim may be left with injured nerves and/or penile arteries that cannot supply enough blood to the penis to provide an erection. Spinal cord injuries that destroy nerve fibers are another cause of erectile dysfunction. Some types of surgery and radiation therapy, such as those for treating prostate, bladder or rectal cancer, also carry a risk of erectile dysfunction. Other chronic disease states associated with a high prevalence of erectile dysfunction include chronic kidney failure, liver failure, sleep apnea and chronic obstructive pulmonary disease (COPD). 

The effects of aging on erectile function have also been studied. Although the rate of erectile dysfunction in the male population increases with age, aging itself does not appear to be the cause. It appears that disease processes such as vascular diseases and diabetes, which may develop as a man ages, are the cause of erectile dysfunction with aging. There may be contributing effects, as well, from years of smoking or alcohol abuse. 

Many medications, including certain blood pressure pills, cold medications, hormones, antidepressants, tranquilizers, alcohol, tobacco, heroin and cocaine, are associated with erectile dysfunction. 

Psychogenic Erectile Dysfunction 

Psychological causes of erectile dysfunction (Psychogenic ED) include stress and anxiety due to marital, financial or other personal problems. It is possible for stress and anxiety to interfere with nerve impulses from the brain when attempting sexual intercourse. "Performance anxiety" is also a common cause of erectile dysfunction. Because of anxiety about the ability to "perform," a man finds he cannot perform - which causes more anxiety, thus completing a vicious cycle. Psychiatric illnesses such as depression can also cause erectile dysfunction. 

It is believed that a portion of men who have organic ED develop psychogenic ED as a result of their anxiety and lack of confidence related to sexual performance. 

Symptoms & Evaluation 

History 

History taking should begin with a brief survey of the patient's demographics, including his age, his partner's age, the duration of his relationship with his partner and the specific dynamics of that relationship. 

Obtaining a good sexual history is imperative. It is important to define which sexual dysfunction the patient is complaining of. It is not uncommon for patients to confuse ED with other sexual dysfunctions such as premature ejaculation, delayed ejaculation or even retrograde ejaculation. Defining a patient's (and partner's) expectations and goals is also of value. 

With regard to erectile dysfunction (ED), the key questions include duration of ED, degree of ED, erectile spontaneity, erectile sustainability, early morning/nocturnal erections, timing of last sexual intercourse and whether the erectile dysfunction is situational or not. A brief assessment of the patient's psychological status is also critical. Specifically, it is important to define if there are overt risk factors for psychogenic ED. 

History taking should then move to the medical and surgical history of the patient. Specific attention should be focused on vascular, neurological and endocrinological issues that may represent risk factors for sexual dysfunction. Obtaining a good medication history is important. Many pharmacologic agents have been associated with erectile dysfunction; however, it is often difficult to determine whether it is the drug itself or the condition for which the patient is being treated that is the primary etiologic factor. A comprehensive social history is also important, which includes questions regarding tobacco, alcohol and illicit drug use. 

There are a number of validated questionnaires available that obtain information regarding a patient's sexual function. These include the International Index Of Erectile Function (IIEF), Sexual Health Inventory For Men (SHIM), and Men's Sexual Health Questionnaire (MSHQ), which are questionnaires routinely used at the Sexual Medicine Program in the Department of Urology at Weill Cornell Medicine. 

Physical Examination 

The physical examination should focus on the following: 

Examination of the penis should focus primarily on the presence of plaques and fibrosis. Examination of the testicles is aimed primarily at defining the presence or absence of masses, and at ascertaining the testicular volume and consistency. All men over the age of 40 years and those with lower urinary tract symptoms undergo digital rectal examination for prostate assessment. 

Adjunctive Testing 

All patients presenting with ED should have their blood pressure measured and a basic laboratory analysis. 

The laboratory evaluation should include a lipid panel to assess for elevated cholesterol levels and serum glucose estimation in an effort to rule out the presence of diabetes. A serum testosterone level, although not imperative, is often also measured. Assessment of liver function tests and thyroid function tests are best reserved for those patients who manifest symptoms and/or signs suggestive of hepatic or thyroid dysfunction. ED is now recognized as a warning sign of silent cardiovascular disease. Certain at-risk patients should be considered for additional testing of cardiac status with an EKG, echocardiogram or stress test. These should be ordered on a case-by-case basis. 

In routine clinical practice, the majority of men presenting with erectile dysfunction do not require any further testing. However a number of investigations exist which are available to aid the clinician in assigning a cause to the patient's ED. Such investigations include: 

Adjunctive investigations may be useful for the following groups of patients: 

Treatment 

The management algorithm at the Sexual Medicine Program at Weill Cornell Medicine - New York Presbyterian Hospital proceeds in a stepwise manner to ensure comprehensive, state-of-the-art treatment in the management of erectile dysfunction (ED). This begins with first line therapy including management of associated medical conditions and psychological support combined with oral medical therapy. Second line therapy includes vacuum erection device therapy, penile injection therapy and transurethral prostaglandin suppository administration. Third line therapy usually involves surgery with implantation of a penile prosthesis. 

Oral Agents (Pills) 

Avanafil (Stendra), Sildenafil (Viagra), Tadalafil (Cialis) and Vardenafil (Levitra, Staxyn) are called inhibitors of phosphodiesterase type 5 (PDE5-I) and they all work by the same mechanism. Viagra® was the first oral agent with proven benefit in the treatment of erectile dysfunction. Nowadays, there are several oral products which differ in time needed to achieve erection, effects of food intake on activity and daily or on-demand use. This gives physicians and patients more flexibility in choosing the best type of medication to suit individual needs. 

The advantage of medications in this group is their simplicity of use. Medications in this group help promote the development and maintenance of an erection. Stimulation is required for these medications to work. It is important to note that these medications do not affect sex drive or libido. Treatment with any of these PDE5 inhibitors allows approximately 65% of men to resume sexual intercourse. Headache, flushing, transient visual disturbances, back pain, and dyspepsia are the most common side effects. 

Vacuum Erection Device 

Vacuum erection devices, also known as vacuum constriction devices, have been utilized for improving erectile rigidity for over a century. Bruising, skin breakdown and penile pain associated with the application of the constriction band are among possible side effects. 

Intraurethral Agents (Suppositories) 

Intra-urethral administration of alprostadil suppository (MUSE™) induces an erection sufficient for sexual intercourse in 30-40% of men. A pellet, the size of a grain of rice, is placed 1 inch into the urine channel following urination while the patient is standing. The reported side effects include pain and dizziness. 

Penile Injections 

Injection therapy represents a cornerstone of ED therapy and remains the gold standard for medical therapy. To date, a number of medications have been used for this purpose, most commonly papaverine, phentolamine and alprostadil. These medications have been administered in a variety of combinations with good effect. The success rate, defined by the production of an erection rigid enough for intercourse, has been in excess of 75%. Disadvantages include the more complex route of administration, potential for bleeding, bruising, penile fibrosis and a higher incidence of priapism (albeit all uncommon side effects). 

Penile Implant (Prosthesis) Surgery 

Penile Implant (prosthesis) Surgery represents a safe and effective means of treating men with ED. Penile prosthesis has the highest satisfaction rates of all treatment options for erectile dysfunction. Patients who attempt, but dislike or fail to achieve, satisfactory results with pills, vacuum devices, suppositories or injections, are counseled about penile implant surgery. 

Penile prostheses can be divided into two main categories: malleable (also known as non-hydraulic or semi-rigid) and inflatable (hydraulic). At our Sexual Medicine Program at Weill Cornell Medicine, 3-piece inflatable penile prostheses are the most commonly implanted. Three-piece inflatable implants have paired cylinders, a small scrotal pump, and a large-volume fluid reservoir (which is placed behind the abdominal wall muscles). 

Prior to surgery, it is important that all patients receive appropriate education concerning the operative procedure and its associated risks and benefits. We also insist on all patients reading device literature and viewing a device video prior to committing to the procedure. Ensuring that the patient has realistic expectations prior to proceeding with implant surgery is essential to ensuring high postoperative satisfaction profiles. Patients are advised that the prosthesis will allow them to achieve a rigid erection on demand and will have no effect on their libido and will not lengthen their penis. Patients are also informed of infection rates (1-3%) and rates of re-operation second to device malfunction (15% within 8 years). 

Penile implants offer the patient a very high level of satisfaction with spontaneity, consistency and rigidity.