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Erectile dysfunction: Symptoms and Diagnosis

• Erectile Dysfunction: Epidemiology and causes
• Erectile Dysfunction: Signs, symptoms and diagnostic workup
• Erectile Dysfunction: Medical and surgical treatment

Review literature: (Lue, 2000) (Porst, 2004).

Signs and Symptoms of Erectile Dysfunction

Evaluation of the Erection Quality:

The severity of the erectile dysfunction can be classified according to the history of the patient (self-assessment), or as an objective examination findings using CIS (combined intracavernous injection and stimulation).

• E0: no tumescence (no increase in volume)
• E1: low tumescence, no rigidity
• E2: average tumescence, no rigidity
• E3: full tumescence, no rigidity
• E4: full tumescence, average rigidity
• E5: full tumescence, full rigidity

The ideal of measuring the strength of the erection is the strength of the axial rigidity: the mass, which does not lead to a penile bend when it is attached to the tip of the penis. Values over 550 g are considered to be sufficient for sexual intercourse.

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 important questions to quickly identify a need for further consultation and diagnosis:

• How do you rate your confidence that you could get and keep an erection? very low (1 point) - low (2 points) - moderate (3 points) - high (4 points) - very high (5 points).
• When you had erections with sexual stimulation, how often were your erections hard enough for penetration? Almost never or never (1 point) - Much less than half the time (2 points) - About half the time (3 points) - Much more than half the time (4 points) - Almost always or always (5 points).
• During sexual intercourse, how often were you able to maintain your erection after you had penetrated (entered) your partner? Almost never or never (1 point) - Much less than half the time (2 points) - About half the time (3 points) - Much more than half the time (4 points) - Almost always or always (5 points).
• During sexual intercourse how difficult was it to maintain your erection to the completion of intercourse? Extremly difficult (1 point) - very difficult (2 points) - difficult (3 points) - slightly difficult (4 points) - not difficult (5 points).
• When you attempted sexual intercourse, how often was it satisfactory for you? Almost never or never (1 point) - Much less than half the time (2 points) - About half the time (3 points) - Much more than half the time (4 points) - Almost always or always (5 points).

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

History:

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

General history: general diseases, neurological diseases, pelvic operations.

Medication: antihypertensive drugs, sedatives, anti-androgens, alcohol, smoking, drugs.

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

Physical examination:

• Signs of hormone disorder: physique and fat distribution, gynecomastia, hair pattern, testicle size.
• Signs of vascular disease: high blood pressure, weak peripheral pulses, leg ulcer.
• Signs of neurological disease: Tremor, paralysis, somatosensory disorders, gait abnormality.
• Diseases of the genital organs: balanitis, phimosis, penile plaques or deviation. Exclusion of testicular tumor. Rectal examination.

Laboratory Tests:

If any pathological results in the basic laboratory evaluation are measured, additional tests are necessary.

Basic laboratory evaluation for erectile dysfunction:

• Glucose, HbA_1C
• Triglycerides, cholesterol
• Blood count
• Creatinine
• Liver function tests
• Testosterone in serum
• TSH
• PSA (Between 45 and 75 years)

Additional tests:

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

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, sonography 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 quality of the erection is evaluated, preferably in combination with a Doppler ultrasound of the penile arteries and veins (see below). If 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). After cavernosal injection, the determination of the peak systolic velocity (PSV), the end-diastolic velocity (EDV) and resistive index in the penile arteries is done every 5–10 min until reaching full erection. If the intracavernosal injection does not lead to an erection within 20–30 minutes, the investigation is repeated after at least one day with the double-dose of PGE₁.

Interpretation of Doppler sonography:

The peak systolic velocity (PSV) should be 25 cm/s. A lower PSV is a sign for 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 for 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 sleep laboratory (polysomnography). The nocturnal erections usually occurs during REM sleep. Ambulatory measurement of the NPT are is also possible (RigiScan etc.). An intact nocturnal tumescence rules out severe organic ED. However, it does not exclude a mild organic cause of erectile dysfunction as e.g., peripheral neuropathy or a mild vascular cause. A pathological NPT measurement correlates well with pathological findings in the Doppler sonography or invasive ED diagnosis.

Indications for NPT:

• suspected psychogenic cause of ED
• sleep disorder with erectile dysfunction
• Part of extended diagnostic workup in case of unknown etiology of ED
• Proof of erectile function or dysfunction (forensic medicine)

Normal values of NPT: 4&dnash;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. The problem 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 continuous filling and the other for continuous pressure measurement. An artificial erection is established with a (high-dose) intracavernosal injection of prostaglandin E1. Diluted contrast medium is used as filling medium. To maintain a corpus cavernosum pressure above 150 mmHg, the flow rate should be below 1 ml/min if the corpus cavernosum is sufficient. 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 certain cases typical wave patterns. Further studies are necessary to standardize CC-EMG.

References

Johannes u.a. 2000 JOHANNES, C. B. ; ARAUJO, A. B. ; FELDMAN, H. A. ; DERBY, C. A. ; KLEINMAN, K. P. ; MCKINLAY, J. B.: Incidence of erectile dysfunction in men 40 to 69 years old: longitudinal results from the Massachusetts male aging study.
In: J Urol
163 (2000), Nr. 2, S. 460–3

Lue 2000 LUE, T. F.: Erectile dysfunction.
In: N Engl J Med
342 (2000), Nr. 24, S. 1802–13

Porst 2004 PORST, H.: Tadalafil, Therapiestrategien bei erektiler Dysfunktion.
Linkenheim-Hochstetten : Aesopus Verlag, 2004

  Deutsche Version: Erektile Dysfunktion