Erectile dysfunction (ED) is recognised as a major public health problem. ED may be due to a wide range of factors, but recent work has focused on the medical and physical aetiology of ED.1 The World Health Organization states that: “sexual health is fundamental to the physical and emotional health and well-being of individuals, couples and families, and to the social and economic development of communities and countries.”3
ED affects the quality of life for both patients and partners and is associated with relationship difficulties. The incidence and prevalence of ED is high worldwide.3
The first large-scale community study—the Massachusetts Male Ageing Study—showed that 52% of men (aged 40 to 70 years) were affected at some time (mild 17%; moderate 25%; severe 10%).2
A Cologne study reported that ED was the most prevalent of the male sexual dysfunctions (prevalence age 30 to 80 years) at 19.2% as compared to 31% for all types of male sexual dysfunction. This study equates to about 26 new cases annually per 1,000 men.4 Whichever study, country or methodology is used, this is clearly a significant condition likely to present regularly to a GP on average between one and four times per month.1
There is in all studies a steep age-related increase. The Cologne study found that of men aged 30–80 years, the prevalence rose from 2.3% at age 30 to 53.4% at age 80 years.4
Only about 10–20% of patients with ED are believed to have a solely psychogenic cause but psychogenic factors are often present in those who are diagnosed as having a physical cause.3

Diagnosis
Assessment of a man with ED includes:
A history, including present and previous erection quality, lifestyle (including alcohol, smoking and illicit drug use), and previous treatments tried.
A focused physical examination, including body weight, waist circumference, heart rate, and blood pressure. Further examination of the genitalia may reveal hypogonadism or malformation such as Peyronie’s disease; digital rectal examination is recommended if there are symptoms of an enlarged prostate.
Investigations, including serum lipid and fasting glucose levels (to calculate 10-year cardiovascular risk) and serum free testosterone.5
Investigations will be directed by the history and clinical findings. The European Association of Urology and the British Society of Sexual Medicine suggest:6
• Fasting glucose or HbA1c and lipid profile for all patients (if not assessed in the previous 12 months).
• Morning sample of total testosterone (free testosterone if available, as it is more reliable in detection of hypogonadism).
• Further tests (for example, PSA) only in selected patients.
• Addition of follicle-stimulating hormone (FSH), luteinising hormone (LH), and prolactin when low testosterone is detected.
Other specific investigations may be indicated and are appropriately arranged by urologists. Indications for referral for these further tests are given below. Further tests include:
• Nocturnal penile tumescence and rigidity studies

Vascular studies
Duplex ultrasound cavernous arteries
Intracavernous vasoactive drug injection
Dynamic infusion cavernosography
Arteriography (internal pudendal)
Neurological studies
Endocrinology work-up
Specialist psychodiagnostic evaluation.
Sex and/or couples therapy
Psychological factors or difficulties in a man’s relationship with his partner can be an important cause of ED. Frequently, a course of sex or couple’s therapy can be very useful in helping couples re-establish a sexual relationship when there has been a long period without sex because of ED. Sex therapy can also be used in combination with other forms of treatment.

Physical causes
Approximately 80% of ED cases are caused by physical conditions that affect the mechanics of an erection such as arterial dilation and nerve sensation. These physical conditions include: 7,8
Hypertension
Hypercholesterolaemia
Cardiovascular disease
Diabetes
Obesity
Metabolic syndrome
Neurological diseases such as multiple sclerosis
Endocrine disorders including testosterone deficiency
Spinal cord injury
Pelvic surgery including prostatectomy
Penile abnormalities including phimosis,
tight frenulum, Peyronie’s disease

Treatment
Lifestyle changes can, in some cases, help to improve the symptoms of ED. These include stopping smoking, reducing alcohol intake, reducing stress and anxiety, and weight loss.9 In addition to lifestyle changes, there have historically been a number of treatment options available (see below).
No one single treatment is suitable for all men with ED meaning many men miss out on the chance for treatment.9-11 Therefore it is important that men with ED have access to a range of therapies providing treatment choice.
Phosphodiesterase-5 (PDE-5) inhibitors are one of the most widely used and effective types of medication for treating ED. They work by temporarily increasing the blood flow to the penis.
In England, three PDE-5 inhibitors are available for treating ED. They are:
sildenafil—sold under the brand name Viagra
tadalafil—sold under the brand name Cialis
vardenafil—sold under the brand name Levitra
Sildenafil and vardenafil work for about eight hours and they are designed to work “on demand”. Tadalafil lasts for up to 36 hours and is more suitable patients who require treatment for a longer period of time, for example, over a weekend.5
A low dose should be tried initially, titrating up if ineffective. A man with erectile dysfunction should receive eight doses of a PDE-5 inhibitor at a maximum dose with sexual stimulation before being classified as a non-responder. Patients should only take one tablet within a 24-hour period.

Vacuum devices
An external cylinder is fitted over the penis to allow air to be pumped out, resulting in engorgement of penis with blood. Studies suggest that whilst two-thirds of patients are unable to achieve ejaculation, 74% are able to achieve orgasm.12 Adverse events include pain, petechiae, bruising and numbness.

Intraurethral alprostadil (prostaglandin E1)
This is a synthetic (man-made) hormone that helps to stimulate blood flow to the penis. Alprostadil is available as an injection directly into the penis—intracavernosal injection. It can also be inserted as a medicated pellet called MUSE® into the urethral meatus and produces an erection after about 15 minutes. 30-65.9% of patients achieve erections sufficient for intercourse. However, it is less effective than intracavernous injections. The most common side-effect is mild penile pain (29-41% of patients).
A topical cream has just been approved. Vitaros (topical alprostadil cream), is now available for prescription in the UK. The new topical cream comes in a single use, disposable applicator that is easy to use and suitable for many of the 2.3 million men with ED in the UK.
It provides healthcare professionals with an alternative, non-invasive option for those men considering alprostadil treatment. After applying the pre-measured amount of cream (100μl) to the tip of the penis, the new skin permeation technology within the cream (NexACT-DDAIP) results in the rapid absorption of alprostadil by loosening the epidermal tight junctions, producing an erection within 5–30 minutes. 

Conclusion

Regular sexual activity is a normal finding in advanced age. ED is a frequent disorder, contributing to dissatisfaction with sex life in a considerable proportion of men. Various causes and management options are available.

Conflict of interest: none declared
References


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3. World Health Organization. http://www.who.int/reproductivehealth/topics/sexual_health/issues/en/ Accessed 10/06/14
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6. Guidelines on Male Sexual Dysfunction: Erectile dysfunction and premature ejaculation, European Association of Urology (2013)
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9. Sexual Advice Association. Impotence or erectile dysfunction. Available at: http://www.sda.uk.net/ed Accessed: May 2014
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12. http://www.nhs.uk/Conditions/Erectile-dysfunction/Pages/Treatment.aspx Accessed 10/06/14