Investigation of Erectile Dysfunction

Matthew Hotston

Introduction

Erectile dysfunction (ED) is defined as ‘the inability to achieve and maintain an erection sufficient to permit satisfactory sexual intercourse’ (NIH Consensus Development Panel on Impotence, 1993), and was believed to have affected over 150 million men in 1995 worldwide, accounting for at least 1 in 10 men in Western countries. Despite the introduction of novel treatments for this condition, this figure is still expected to rise to over 320 million by the end of 2025 (Ayta et al., 1999). It is therefore essential that the clinician performs an appropriate, thorough and directed investigation of a patient presenting with ED to ensure the maximum chance of success in subsequent treatment (Table 9.1).

Table 9.1 Clinical assessment of erectile dysfunction

History	Medical
	Psychosocial
	Sexual
Physical examination
Laboratory tests

Each consultation should commence with a full clinical history, including sexual, psychosocial and medical, a physical examination, and routine laboratory tests. Following this, confirmation or further evaluation can be pursued with additional diagnostic approaches.Throughout all the following investigations described, it is essential that the physician creates an atmosphere of calm, empathy and responsiveness, so that the patient can cooperate openly and fully. It must be emphasized that there is no standard approach to investigating ED, and so it is essential to appreciate and understand the tests available to gain a successful outcome. The extent of investigation needs to be tailored to the individual’s wishes. The following is a concise approach to initially managing the patient in the clinic setting, followed by a description of diagnostic studies currently available.

Patient assessment

Clinical history

The clinical history is the most important part of the diagnostic evaluation of the patient with ED. ED may represent an early marker of cardiovascular disease and even depression, which can then be addressed appropriately (Montorsi et al., 2003a). The initial focus should address whether the patient does have ED, and not a dysfunction of libido, ejaculation or orgasm. Various questionnaires have been formulated to aid the physician in this manner, as well as determining its severity. The most commonly used is the International Index of Erectile Function (IIEF; Table 9.2).

This is composed of 15 questions (full version), which can be completed prior to consultation (Rosen et al., 1997). Specifically, it is important to determine the time of onset and duration, the particular situations where occurring, and the intensity of the problem. This is in order to classify the nature of ED, so any further diagnostic evaluation can become more focused. Essentially, ED can be of psychogenic or organic cause, or indeed mixed, which is thought to be currently the most common aetiology (Melman and Gingell, 1999). Those of an organic nature tend to report an insidious onset of symptoms, which is not situational, with poor or absent nocturnal and morning erections. Directed questions can include assessment of the quality of the
erection. A reduction in penile rigidity (normally expressed as a percentage of their best) and sustainability may indicate a haemodynamic component, particularly veno-occlusive dysfunction. Pain or deformity of the penis may indicate Peyronie’s disease (Roddy et al., 1991) (9.1).

Table 9.2 IIEF-5 scoring system (abridged version)

		Score
Over the past six months:		1	2	3	4	5
1.	How do you rate your confidence that you could get and keep an erection?	Very low	Low	Moderate	High	Very high
2.	When you had erections with sexual stimulation, how often were your erections hard enough for penetration?	Almost never or never	Much less than half the time	About half the time	Much more than half the time	Almost always or always
3.	During sexual intercourse, how often were you able to maintain your erection after you had penetrated (entered) your partner?	Almost never or never	Much less than half the time	About half the time	Much more than half the time	Almost always or always
4.	During sexual intercourse how difficult was it to maintain your erection to the completion of intercourse?	Extremely difficult	Very difficult	Difficult	Slightly difficult	Not difficult
5.	When you attempted sexual intercourse, how often was it satisfactory for you?	Almost never or never	Much less than half the time	About half the time	Much more than half the time	Almost always or always
The IIEF-5 score is the sum of questions 1 to 5. The lowest score is 5 and the highest score 25.

A full current and past medical history should be acquired, in order to elucidate relevant risk factors. This should involve a cardiovascular, neurological, metabolic and hormonal, and psychiatric history. Any past history of surgery and trauma, including complications, should be noted. A drug history is important, as there are many medications, such as antihypertensives (diuretics, β-blockers) that can cause impotence (Slag et al., 1983). Recreational drugs in the form of cigarette smoking, alcohol, marijuana and cocaine, are also associated with ED. Common causes of arterial insufficiency that can be identified include diabetes, hypertension, smoking, hyperlipidaemia and previous pelvic surgery. Corporal veno-occlusive dysfunction may occur due to previous injury or surgery to the penis, Peyronie’s disease, as well as diabetes and hyperlipidaemia leading to changes in the fibroelastic properties of the corporal tissue (Roddy et al., 1991).

9.1 Peyronie’s disease.

Physical examination

A full physical examination is mandatory, to assess for any direct causes, as well as any associated risk factors. The external genitalia should be examined for general sensation and anatomical deformities, such as Peyronie’s plaques.

A rectal examination may reveal prostate cancer, prostatitis and reduced anal sphincter tone. The bulbocavernosal reflex can also be performed. The endocrine system should be assessed in the form of general thyroid status, looking for gynaecomastia (9.3) and small testes, suggesting hypogonadism (9.4).

The patient’s vascular status should be sought through blood pressure measurement, peripheral pulses and any evidence of peripheral vascular disease (9.5).

Laboratory tests

Most patients should be offered basic laboratory tests, such as baseline haematological and biochemical blood tests, lipid profile, and a random blood plasma glucose sample. Other tests can be directed through clinical suspicion, such as liver function tests, serum testosterone, prolactin, thyroid function, follicle-stimulating hormone and luteinizing hormone tests.

9.2 Orchidometer for measuring testis size.

9.3 Gynaecomastia of hypogonadism.

9.4 Small testes of hypogonadism.

9.5 Signs of peripheral vascular disease.

Non-surgical management of erectile dysfunction

Following a full history and examination, the treatment options can be discussed with the patient. It is reasonable at this point to commence a trial of medical management, provided there are no contraindications. However, it is important to explain that this may be unsuccessful, but that there are further investigative studies that may be of benefit, and surgical approaches for selected cases. The management of ED has changed dramatically from the common use of penile prostheses in the 1970s, to intracavernosal injections, and now the choice of type 5 phosphodiesterase (PDE5) inhibitor medications, and even transurethral therapy (Table 9.3). The initial approach should always be to address the patient’s lifestyle characteristics. Smoking cessation, diet modification (including reduced alcohol intake), weight reduction (in obesity) and stress management are all simple but effective measures.

Oral therapies

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