Gordon Muir
Consultant Urologist, King’s College Hospital London
Special interests: Urological cancer. Male sexual health. Prostatic diseases
Erectile dysfunction is the term now used for the consistent inability to get or maintain an erection of sufficient rigidity for satisfactory sexual intercourse. The lay term for this problem, now regarded by some as of suspect political correctness, is impotence. Indeed this term any give a better idea as to how a man with ED feels, as the loss of manhood, power and status make a man feel generally impotent.
Despite ill-advised comments in the media, it is a serious condition and one that affects both partners in a relationship. There are measurable adverse events which occur as a result of ED and measurable benefits associated with its successful treatment.
It is often not realised that many men presenting with ED have potentially serious underlying medical conditions, leading to the prospect of early intervention for such conditions as diabetes, cardiovascular disease and depressive illnesses. The attention of the patient to his erection is also a powerful aid to reinforcing advice on general lifestyle changes!
This review looks at the available diagnostic and treatment options and their place in management of this distressing condition. It will not seek to address the arguments over GP resources or the place of the NHS in managing non life threatening issues: it my view that if a man seeks professional help over an embarrassing issue he deserves to be taken seriously. Rationing or exclusion of treatments under the NHS should only happen after a structured debate looking at the overall costs and benefits of all therapies.
Erectile dysfunction is common in all age groups, with the incidence increasing as men get older.
Over five per cent of men in their forties will report complete impotence. It is of course important to realise what is meant when men report erection difficulties: almost all men will have transient failures associated with life events, but if the problem is persistent reassurance alone will not do as treatment.
In contrast to the commonly held belief that ED is more common in older men due to decreasing androgen levels, impotent aged men do not seem to have significantly lower serum androgens than potent age matched controls.
Those readers with young male children (who have a low serum testosterone before puberty) will know that erections are quite capable of occurring without high levels of serum androgens.
Thus it would seem that an underlying increase in the frequency of co-morbidity is likely to be to blame.
Men with impotence have a significantly increased risk of suffering form heart and other arterial disease, diabetes, depression and smoking. It is therefore impossible to propose that these patients, who represent a poorly attending group in primary care, should not at least be seen for examination and screening of underlying disease.
Most men with erectile dysfunction will present a mixed picture of physical and psycogenic origin. While differentiation may be made see below) on the grounds of the history, it is inapproproate to make a vlaue judgement about whether or not a man deserves treatment based on this. We do not refuse to treat patients with chronic pain syndromes for which no physical cause is obvious!
Every study which has looked at the psychological impact of ED has found a negative correlation between the presence of impotence and general well being and quality of life. Anxiety and depression, along with self-esteem, are adversely affected. Treatment is capable of reversing these problems.
Currently little work has been done looking at the impact of ED on the quality of relationships and its impact on partners, but what evidence exists is similar to the effect on the patient
The main place of physical examination and investigation in the management of primary care is, arguably, in diagnosing underlying disease. A brief and structured approach is outlined below.
History
In terms of the history that should be taken, a few brief and direct questions need to be asked. Be aware that different patients have different ideas of what sexual dysfunction means, so the direct approach is mandatory both to get an accurate picture and to avoid wasting time on the interview. It may be difficult at first for the physician to be very direct with patients in these matters, and one must be realised that in some cases these are matters doctors do not feel comfortable discussing even with their own partners. Patients who are questioned directly and without embarrassment will however feel less embarrassed and more secure themselves.
The examination can be limited to an assessment of the patient’s blood pressure and external genitals. Further examination will be dictated by the doctor’s own interest in screening the patient for co-morbidity.
In my practice I check
the breasts (to exclude gynaecomastia)
carotid, aortic and femoral pulses (major peripheral vascular disease)
knee, ankle and bulbo-urethral* reflexes (undiagnosed neuropathy)
The prostate (prostate disease is no more common in impotent men than controls, but I would feel foolish sending an undiagnosed prostate cancer back to one of my GP colleagues!)
This examination can be carried out in only a few minutes.
The only mandatory test is of a urine or blood sample for glucose.
It is most unusual to find a man with significantly low testosterone in the presence of a normal libido and secondary sexual characteristics. If these exist, it is important to check the level of sex hormone binding globulin (SHBG), since the ratio between this carrier molecule and testosterone is what determines the biologically available testosterone. Further investigation of men with low testosterone is most appropriately carried out in a specialist centre.
If signs of general ill health are present then checks on renal and hepatic function are appropriate, along with a full blood count and possibly thyroid function check.
An argument can be made for checking both the serum lipids and the PSA depending on local and national screening guidelines.
Patients who should always be referred or discussed with a specialist are:
Young men who have never been able to have an erection
Patients with a sudden onset of impotence liked to trauma
Men with genital or prostatic abnormalities
Those with abnormalities found on any of the screening tests above.
It is essential that the patient be involved in the choice of management, along with his partner where possible. Until a few years ago the options for management of impotence were limited, whereas now a large number of treatments exists.
As stated above it is essential to find out what the patient and his partner expect and hope from any treatment in order for a management plan to be agreed. I would point out that the high response rate with the available options makes treatment very rewarding: these patients are grateful for success!
Treatments can broadly be divided into psychological, pharmaceutical and physical therapies. All of the drugs available act by increasing the blood flow in the cavernous bodies and allowing tumescence then rigidity.
Most men have some degree of psychological involvement in their erectile dysfunction. Equally, many men with a psychological problem will also have a co-existent physical one. The history is most important in making this distinction.
Counselling must involve a significant investment of time and commitment by the patient, with well-motivated patients in good centres achieving benefits in up to 80% of cases. Default rates can however be high, and the desirability of involving the partner may be seen as either a good or a bad thing depending on the individual.
Few controlled studies on counselling outcomes exist, and the availability of services in different parts of the country varies.
Where counselling is effective it is a non-invasive therapy which can address the underlying problems both with an individual patient and in a relationship.
The place of a combination of counselling and medical therapy (mirroring treatment in depressive illness) has not really been addressed but may be of considerable interest in the future.
The advent of Sildenafil (Viagra), a selective inhibitor of phosphodiesterase type 5, dramatically changed the face of therapy in ED. It has been demonstrated in well conducted placebo control studies to be significantly superior to placebo, giving good results in 46 –88% of users depending on the patient group. Interestingly, patients deemed to have primary psychogenic impotence are among the best responders to the drug.
Despite the enormous amount of media hype surrounding the drug and its safety profile, follow up of many thousands of men who have taken the drug shows no obvious cardiac or other risk associated with its use. Here one must stress that any treatment which allows a man with serious cardiac risk factors to have intercourse may put him at risk, so the general assessment mentioned earlier is critical.
Here it must again be stressed that by virtue of its potentiation of the effects of nitric oxide, Sildenafil is absolutely contraindicated in men taking any nitrate drugs. Profound systemic hypotension can result, and patients should be aware that amyl nitrate (“poppers”) used recreationally will have the same risk.
Sildenafil is available in three dose (25mg, 50mg and 100mg) with a dose response evident both from trials and from patients’ preferences. Men take the drug one to two hours prior to planned intercourse. It must be stressed that the drug does not work as some others in that sexual stimulation is necessary for an erection to be obtained with the use of the drug.
It is also important that men do not give up after the first attempt: up to eight treatments may be needed for a good response to become apparent.
Cialis (Tadalafil) and Levitra (Vardenafil) are now available as alternatives to Viagra. Of these drugs, Cialis has a longer duration of action and is preferred by some men who wish to have longer period in which intercourse is possible. Levitra has a similar profile to Viagra: although a few studies have suggested some men who do not respond to Viagra may benefit from vardenafil, there were serious flaws in these stuies and there seems to be little difference in practice.
The use of PDE-5 inhibitors is the first step, indeed almost a diagnostic test, for the management of men with impotence with no contra-indications. I
Until recently, the drug Yohimbine was commonly prescribed for men without a significant physical component to their impotence. It has a side effect profile significantly higher than that of Sildenafil and there is only weak evidence for its efficacy, so as an unlicensed drug its use cannot be recommended.
Not surprisingly, a number of new oral agents are in development and testing. It may be excepted that at least three new oral therapies will reach the market in the next two years. Side effect profiles, cost and patient suitability will all be factors in proving the place of new therapies.
Direct intracavernosal injection of vasoactive agents has been practised for over a decade. While many agents have been used with success, the only freely available licensed product in the UKat present is prostaglandin E1 (Caverject). The drug moxisylate (an alpha-blocker) is licensed for this approach but has been withdrawn from the UK market by the company.
Over 75% of men will be able to attain an erection with intracavernosal therapy; while an automatic erection is obtained, concomitant sexual stimulation will enhance the effects.
Obviously there are drawbacks to the use of such treatment, not least being the reaction of most men on being invited to put a needle into their own penis! The injection itself in fact rarely hurts, although around 5% of men experience burning pain or discomfort afterwards. It is also a problem in men who have visual or co-ordination difficulties and this remains true despite the efforts of the pharmaceutical companies in adapting the delivery systems to become more patient friendly.
Perhaps the main reason that up to 40% of users will no longer be injecting after a year is the feeling of a physical barrier that any external device can create between a couple.
It is likely that higher dose formulations, possibly in combination with other vasoactive agents, will be developed for those men in the future who fail to respond to oral agents.
This system (MUSE) consists of a prostaglandin pellet is absorbed after urethral insertion and transmitted to the corpora cavernosa by venous communications. While the applicator is small, discrete and easy to use it is handicapped by a significant minority of men (up to 30%) who report burning and discomfort after use. Although high doses of prostaglandin are used, the effectiveness seems less easy to predict than using intracavernosal route.
Currently it is difficult to assess the place of MUSE when compared to sildenafil and trials will be needed to define its long-term usefulness. The route of administration is nevertheless of considerable interest for a number of possible drugs.
These devices use a cylinder with a pump by which negative pressure induces an erection, following which a constriction ring at the base of the penis maintains rigidity. The resulting erection may sometimes feel heavy or cold, but many men using pumps are very satisfied, particularly men in a stable relationship. A major limitation at present is the fact that even though this option would seem to be the cheapest for the NHS in the long term for an individual patient, the pump systems are generally available for private purchase only (They cost between £130 -£325 depending on the model and manufacturer).
Vascular penile surgery has only an extremely limited place: where carried out it should be in specialist centres as part of ongoing clinical studies.
Surgery for the correction of Peyronie’s disease will only rarely lead to a significant improvement in co-existing erectile dysfunction and patients in this situation should be counselled about the need for further therapy once the penis has been straightened. The use of a penile prosthesis is often a valuable first option in these patients.
The implantation of penile prosthesis gives a reliable and effective long-term solution but at the cost of between £700 -£2900 in the cost of the implant and the risk that should the device become infected (2%-12%) irreversible penile scarring may result.
Erectile dysfunction is an under-diagnosed and under-resourced condition, which causes distress to men and their partners
Evaluation and diagnosis are simple, inexpensive and may pick up a number of serious co-morbid conditions at an early stage
Treatment is relatively simple for most men and rewarding for patient and physician alike.
The place of therapy for erectile dysfunction may need to wait upon Government rationing policies, but primary care doctors need to be aware of the problem and its solutions.