Dr. med. Dirk Manski



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Erectile dysfunction: Symptoms and Diagnosis

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).

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:

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)

Laboratory Tests:

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

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 textbooks of internal medicine.

Pharmaco-test (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, even without sexual stimulation. The quality of the erection is evaluated, preferably in combination with a Doppler ultrasound of the penile arteries and veins (see below). Pharmaco-testing can be repeated the next day with a double dose, if a sufficient erection is not acchieved. Fears or excitement 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 (Doppler) Ultrasound Imaging of the Penile Blood Vessels

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 2 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:

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 and to plan vascular reconstruction, if warranted.

Cavernosography and Cavernosometry:

20 minutes after intracavernosal injection of prostaglandin, the corpus cavernosum is punctured with a butterfly needle and a diluted contrast medium is infused (60-120 ml/min). Every 15 s X-rays are obtained. The cavernosography is terminated with a full erection or when the venous leackage can be described (location and extent). Venous leakage is possible via the dorsal penile vein, intercrural veins and drainage through the corpus spongiosum.

Cavernosography can be combined with cavernosometrie. It is necessary to puncture the corpus cavernosum with two needles, one for continuous filling and the other for continuous pressure measurement. The flow rate for a cavernosal pressure over 150 mmHg should be below 20 ml/min. Alternatively, the filling of the corpus cavernosus is done with a height of 160 cm (equivalent to 120 mmHg), this should raise the cavernosal pressure over 110 mmHg. With venous leakage, the cavernosal pressure remains well below 110 mmHg.

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.







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References

Braun u.a. 2000 BRAUN, M. ; WASSMER, G. ; KLOTZ, T. ; REIFENRATH, B. ; MATHERS, M. ; ENGELMANN, U.:
Epidemiology of erectile dysfunction: results of the Cologne Male Survey.
In: Int J Impot Res
12 (2000), Nr. 6, S. 305–11

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