Dr. med. Dirk Manski

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Erectile dysfunction: Symptoms and Diagnosis

Signs and Symptoms of Erectile Dysfunction

Graduation of the erection hardness:

The graduation of the erection hardness can be used during history taking (self-assessment), or as an objective tool during examination using CIS (combined intracavernous injection and stimulation). The most common used graduation is the erection hardness score (EHS) (Mulhall et al., 2007)

IIEF questionnaires (International Index of Erectile Function)

The original IIEF (International Index of Erectile Function) questionnaire was validated using 15 questions, which helped in assessing the severity of the disease and the efficacy of treatment. The IIEF-5 questionnaire consists of five questions to identify a need for further consultation and diagnosis:

Evaluation of the IIEF-5: no erectile dysfunction (22–25 points), mild erectile dysfunction (17–21 points), mild to moderate erectile dysfunction (12–16 points), moderate erectile dysfunction (8–11 points), severe erectile dysfunction (less than 8 points).

Diagnosis of Erectile Dysfunction


Sexual history: duration of ED, graduation of erection, partner history, impact on quality of life, libido, nocturnal erections.

General history: ask for internal diseases, neurological diseases, and pelvic operations.

Medication: is the patient taking antihypertensive drugs, sedatives, or anti-androgens? Alcohol, smoking, or drug abuse?

Quantification of erectile dysfunction with a questionnaire (IIEF-5, see above)

Physical examination:

Laboratory Tests:

Additional tests are necessary if pathological results are measured in the basic laboratory evaluation.

Basic laboratory evaluation for erectile dysfunction:

Additional tests:

In case of low testosterone: prolactin, LH, FSH, DHEA, SHBG, free testosterone. In case of other pathological results, please refer to internal medicine textbooks.

Cardiovascular workup:

The new manifestation of erectile dysfunction is also a clinical sign of an impending cardiovascular event such as myocardial infarction or apoplexy. Depending on the clinical situation (age, risk factors, medication), appropriate internal medicine investigations (including RR measurement, exercise ECG, and ultrasound imaging of the carotids) should be recommended.

Intracavernosal Injection

Intracavernosal injection (ICI) of a low dosage of prostaglandin E1 (PGE1) (5–10 mg) from laterally into the base of the corpus cavernosum with a thin needle (27G) leads to an erection. The combination with genital or audiovisual sexual stimulation improves the response to the injection. The erection quality is evaluated, preferably with a Doppler ultrasound of the penile arteries and veins (see below). If an erection does not occur within 30 min, the study is discontinued. Pharmaco-testing can be repeated the next day with a double dose (maximum dose 40 μg of prostaglandin), if a sufficient erection is not acchieved. Anxiety of the patient can lead to a false-negative pharmaco-testing.

Interpretation of intracavernosal injection: if a low dose leads to a full erection (in patients with erectile dysfunction), neurogenic, psychogenic, or hormonal erectile dysfunction is likely. If a moderate or high dose is necessary for an erection, vascular ED is probably. If even a high dose does not lead to an erection, erectile dysfunction due to cavernosal or veno-occlusive diseases is likely.

Duplex Ultrasonography of Penile Blood Flow

Duplex ultrasound imaging of the penile vessels is combined with intracavernosal injection of prostaglandin E1 (see above). The peak systolic velocity (PSV), the end-diastolic velocity (EDV), and the resistive index in the penile arteries is measured every 5–10 min until reaching full erection. If the intracavernosal injection does not lead to an erection within 20–30 minutes, the investigation may be repeated after at least one day with the double dose of PGE1.

Interpretation of Doppler sonography:

Normal peak systolic velocity (PSV) values are 35–45 cm/s. A PSV <25 cm/s indicates arterial insufficiency. During full erection, the end-diastolic velocity (EDV) should be less than 5 cm/s. Higher values, especially with normal PSV, are a sign of veno-occlusive disorders or diseases of the corpus cavernosus. The resistive index (RI) is close to 1 during full erection since the end-diastolic velocity should be very low. An RI less than 0.75 indicates a veno-occlusive disorder if the PSV is normal. The diagnostic value of Doppler sonography with pharmaco-testing reaches the diagnostic value of angiography and cavernosometry and is less invasive.

Optional and Experimental Diagnostic Tests for Erectile Dysfunction

Nocturnal penile tumescence measurement (NPT):

Nocturnal penile tumescence measurement is usually done in a sleep laboratory (polysomnography). Nocturnal erections usually occur during REM sleep. Ambulatory measurement of the NPT is also possible (e.g., RigiScan). An intact nocturnal tumescence rules out severe organic ED. However, it does not exclude a mild organic cause of erectile dysfunction. A pathological NPT measurement correlates well with pathological findings in the Doppler sonography or invasive ED diagnosis.

Indications for NPT:

Normal values of NPT: 4–5 erectile episodes per night, mean duration 30 min, more than 70% rigidity (measured with RigiScan).

Penile Angiography:

Selective angiography of the internal pudendal artery is done after intracavernosal injection of prostaglandin. The study has a high sensitivity in suspected vascular erectile dysfunction. Problematic is the invasive character of the study and the highly variable anatomy of the penile arteries. Penile angiography is indicated for erectile dysfunction after pelvic trauma of young men and to plan vascular reconstruction, if warranted.

Dynamic infusion cavernosometry and cavernosography (DICC):

Two cannulas are used to puncture the corpus cavernosum, one for filling and the other for pressure measurement. An artificial erection is established with a (high-dose) intracavernosal injection of prostaglandin E1. A diluted contrast medium is used as filling medium. A healthy corpus cavernosum only needs a flow rate below 1 ml/min to maintain a cavernosal pressure above 150 mmHg. In case of venous insufficiency, a higher flow rate is needed. After stopping the infusion at a pressure of 150 mmHg, the pressure drop within 30 s is less than 20 mmHg in a sufficient corpus cavernosum and is much higher in venous insufficiency (Gao et al., 2019).

The location and extent of venous leakage can be assessed by radiographs in different planes. Venous leakage is possible via dorsal veins, intercrural veins and outflow via the corpus spongiosum distally (glandocavernous) or proximally (spongiocavernous).

Corpus cavernosum-EMG (CC-EMG):

Corpus cavernosum-EMG is a needle EMG from the erectile tissue, which produces a typical wave-wave activity in the non-erect penis. By visual or pharmacological sexual stimulation, wave-wave activity is inhibited and correlates with smooth muscle relaxation. The lack of relaxation of the corpus cavernosum is a caused by different forms of erectile dysfunction. Arterial insufficiency, neurological diseases, or cavernosal disorders produce, in some instances, typical wave patterns. Further studies are necessary to standardize CC-EMG.

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  Deutsche Version: Erektile Dysfunktion