Erectile dysfunction (ED) is a complex condition involving psychosocial and biological factors. It is defined as the persistent inability to achieve or maintain penile erection sufficient for satisfactory sexual performance. ED is a common disorder of male sexual function, affecting all age groups with a considerable impact on quality of life.
The penis is composed of three bodies of erectile tissue running in paralel; the corpus spongiosum, encompassing the urethra and terminating in the glans penis; and the two corpora cavernosa (CC) which function as blood-filled capacitors providing structure to the erect organ
The penile CC are highly specialized vascular structures that are morphologically adapted to their function of becoming engorged during sexual arousal. The trabecular smooth muscle constitutes approximately 40-50% of tissue cross-sectional area, as assessed by histomorphometric analysis. There are three main arteries in the penis: cavernosal, dorsal, and bulbourethral. All three arise from a shared branch of the internal pudendal artery and provide an extensive anastomotic network
How do Erections Work?
During sexual arousal, the brain signals nerves to release chemicals that increase blood flow into the penis. Blood flows into two erection chambers made of spongy muscle tissue (the corpus cavernosum). The corpus cavernosum chambers are not hollow. During an erection, the spongy tissues relax and trap blood. The blood pressure in the chambers make the penis firm, causing an erection.
When a man has an orgasm, a second set of nerve signals reach the penis and cause the muscular tissues there to contract. Blood is released back into a man’s circulation and the erection comes down. When you are not sexually aroused, the penis is soft and limp. Men may notice the size of the penis varies with warmth, cold or worry. This is normal, and reflects the balance of blood coming into and leaving the penis.
What are the Symptoms of ED?
Symptoms for ED may include:
• Getting an erection, but it not lasting long enough for sex
• Getting an erection, but not when you want to have sex
• Not being able to get an erection at all When ED becomes bothersome, your primary care provider or a urologist can help. ED may be a major warning sign of cardiovascular disease. It can signal blockages in a man’s vascular system. Some studies have shown men with ED are at higher risk of a heart attack, stroke or circulatory problems in the legs.
What Causes ED?
Finding the cause(s) of your ED will help to treat the problem. ED can result from health problems, emotional issues, or from both. Some known risk factors for ED are:
• Injury to the pelvis
• Surgery from cancers of the prostate, colon, rectum or bladder
• Heart disease
• Peripheral artery disease (narrowed arteries slowing blood flow)
• High blood pressure
• High blood sugar (diabetes)
• Alcohol use
• Drug use
• Smoking or vaping
• Some medicines
• Emotional stress from depression, anxiety or relationship problems. Even though ED becomes more common as men age, growing old does not always cause ED. Some men are sexually functional into their 80s.
Treatment of ED
As a rule, ED can be treated successfully with current treatment options, but cannot be cured, with the exception of:
• Psychogenic ED: psychosexual therapy may be given, either alone or with another therapeutic approach, but takes time and has had variable results.
• Post-traumatic arteriogenic ED in young patients: surgical penile revascularisation has a 60-70% long-term success rate.
• Hormonal causes of ED: testosterone replacement therapy is effective, but should only be used after other endocrinological causes for testicular failure have been excluded. Currently, it is contraindicated in men with untreated prostate cancer, unstable cardiac disease and severe LUT obstruction. Close follow-up is necessary, including digital rectal examination (DRE), serum prostate-specific antigen (PSA) and haematocrit assessment, as well as monitoring the development of hepatic or prostatic disease.
Oral drugs known as PDE type-5 inhibitors increase penile blood flow. These are drugs that are taken as a pill by mouth. The only oral agents approved in the U.S. by the Food and Drug Administration for ED are:
• Viagra® (sildenafil citrate)
• Levitra® (vardenafil HCl)
• Cialis® (tadalafil)
• Stendra® (avanafil)
For best results, men with ED should take these pills about an hour or two before having sex. PDE-5 inhibitors improve blood flow to create a strong erection. To work, they require normal nerve function to the penis. About 7 out of 10 men do well and have better erections with these agents. Response rates are lower for people with diabetes or cancer.