Diagnosing Erectile Dysfunction: Which Tests Are Done?
Correct treatment for erectile dysfunction begins with an accurate diagnosis. What do the history, blood tests, penile Doppler ultrasound and nocturnal erection testing show, and which patient needs which investigation?
Erectile dysfunction is not the name of a single disease but a complaint that can have many different underlying causes. Deterioration in vascular health, hormonal imbalance, diseases affecting the nervous system, medications in use and psychological factors are all among them. Each of these causes calls for a different treatment approach.
Despite this, a significant proportion of men start taking medication without any detailed assessment. This approach may work in the short term; but it can allow an underlying health problem to be missed and can also mean the expected benefit from the drug is not achieved. This article covers how the diagnostic process works in erectile dysfunction, what each investigation shows and which patients need further testing.
Why does diagnosis matter so much?
Diagnosis in erectile dysfunction has two separate purposes. The first is to establish the cause of the complaint so that treatment starts at the right step. The second is often overlooked: erectile dysfunction itself may be the first sign of a health problem that has not yet produced symptoms.
The arteries of the penis are narrower than the large vessels elsewhere in the body. The effects of deterioration in the vessel wall may therefore appear here earlier than in the coronary or cerebral arteries. This means erectile dysfunction must be assessed in some patients as an early warning of cardiovascular disease.
Similarly, undiagnosed diabetes, testosterone deficiency, thyroid disease and sleep apnoea may come to light for the first time during an assessment carried out for this complaint. The diagnostic process is therefore an assessment not only of sexual function but of general health.
What is asked at the first consultation?
The most decisive step in the assessment is a detailed history. In most patients the direction of the diagnosis is largely determined in this consultation, before any test is performed. The following topics are usually covered:
- Onset of the complaint: Did it begin suddenly, or develop gradually over months or years?
- Consistency: Does it occur every time, or does it vary with the situation?
- Morning and night-time erections: Are they still present, reduced, or absent altogether?
- Accompanying complaints: Reduced sexual desire, premature ejaculation, curvature or pain in the penis.
- Coexisting conditions: Diabetes, hypertension, high cholesterol, heart disease, neurological conditions.
- Current medication: Blood pressure drugs, antidepressants, prostate medication and herbal products.
- Lifestyle: Smoking, alcohol, inactivity, weight, sleep pattern and snoring.
- Psychological and relationship factors: Stress, anxiety, depression, difficulties within the relationship.
Standard questionnaires may also be used at this consultation. By expressing the severity of the complaint numerically, these forms are also useful for tracking change after treatment.
What is looked for on physical examination?
The examination covers both the genital area and general condition. Palpable hardness or plaque in the penis, the size and consistency of the testes, hair distribution, breast tissue enlargement and assessment of the prostate are the topics addressed at this stage.
In addition, blood pressure measurement, waist circumference, pulse and, where needed, assessment of the leg vessels give an indication of vascular health. Where a neurological condition is suspected, sensory and reflex examination is also performed.
Which blood tests are requested?
Blood tests are requested both to investigate the cause of erectile dysfunction and to detect conditions that may accompany it. The investigations commonly requested are:
- Fasting blood glucose and HbA1c: To detect diabetes or assess how well it is controlled.
- Lipid profile: For risk assessment relating to vascular health.
- Total testosterone: Taken in the morning, preferably fasting; repeated if low and supported with further hormone tests where needed.
- Prolactin and thyroid hormones: Assessed in cases where a hormonal cause is suspected.
- Complete blood count, kidney and liver function: To assess general condition.
- PSA: Requested in patients where it is indicated by age and prostate symptoms.
The treatment plan changes in patients found to have low testosterone, so it is important that hormonal assessment is not omitted in the evaluation of erectile dysfunction.
How are psychological and physical causes distinguished?
One of the questions patients ask most often is whether the problem is “psychological or physical”. This distinction can largely be made from the history.
Complaints of sudden onset, occurring in particular situations, where morning and night-time erections are preserved and which arise with one partner or under particular circumstances point more towards a psychological origin. Conversely, organic causes come to the fore in patients whose complaint developed gradually, persists in all situations, where morning erections have diminished or disappeared and where vascular risk factors are present.
This distinction is not a firm boundary; in a significant proportion of patients both components are present together. In someone with a vascular problem, for instance, performance anxiety developing over time can worsen the picture. The treatment plan therefore often addresses both aspects.
What is penile Doppler ultrasound and what does it show?
Penile Doppler ultrasound is an imaging method that assesses blood flow in the vessels of the penis. During the examination a drug applied to the penis is usually used to initiate an erection, after which arterial and venous flow are measured.
The examination primarily identifies two situations:
- Arterial insufficiency: Inadequate blood flow into the penis, indicating deterioration in vascular health.
- Venous leak (penile venous insufficiency): Blood not being retained within the erectile tissue, which can present as an erection that begins but cannot be maintained.
This examination is not needed in every patient. It is generally requested in erectile dysfunction developing at a young age without obvious risk factors, in those with a history of trauma, in cases where Peyronie's disease is suspected and in patients for whom surgery is planned.
When is nocturnal erection testing used?
Erections normally occur several times during sleep. Nocturnal erection testing is an investigation that records the presence and quality of these erections.
The underlying principle is this: if erections are preserved during sleep, the erectile mechanism is considered to be working physically, which supports a psychogenic origin. If no erections occur during sleep either, an organic cause comes to the fore.
This investigation is not used in every patient in routine practice; it is considered in cases where the history is not sufficiently informative and the distinction between psychogenic and organic causes remains unclear.
Which patients need further investigation?
In most patients with erectile dysfunction, the history, examination and basic blood tests are sufficient to plan treatment. Further investigations generally come into consideration in the following situations:
- Complaints developing at a young age without obvious risk factors
- A history of trauma to the pelvic area or the penis
- The presence of Peyronie's disease or marked penile curvature
- Examination and laboratory findings suggesting a hormonal disorder
- Failure to achieve the expected response to appropriate treatment
- Patients for whom surgical treatment is planned
The diagnostic process in erectile dysfunction is an assessment covering not only the patient's sexual complaint but also their general health. A detailed history and examination determine the direction in most patients; blood tests reveal accompanying conditions; and investigations such as Doppler ultrasound and nocturnal erection testing are needed in selected cases. Assoc. Prof. Dr. Zülfü Sertkaya practises in urology and andrology in Istanbul; diagnosis and treatment planning in erectile dysfunction are carried out with individual assessment and confidentiality.