Review Question - QID 106997

In patients presenting with erectile dysfunction (ED), evaluation of nocturnal tumescence should be performed to determine whether the cause is organic or psychogenic.

Impotence is defined as the inability to obtain or maintain an erection. The presence of nocturnal tumescence suggests a psychogenic, rather than organic cause of impotence. Nocturnal tumescence can be measured with a snap gauge or a strain gauge (Illustrations A and B). Age is one of the most common risk factors for ED; patients <40 years are most likely to have a psychogenic cause of ED, while patients >60 years are likely to have an organic cause of ED. Organic causes of ED include renal failure, neuropathy, and medication side effects (especially selective serotonin uptake inhibitors).

Heidelbaugh reviews the management of ED. He notes that up to 1/3 of men will experience ED at some point in their lives. Modifiable risk factors for ED include obesity, smoking, and a sedentary lifestyle. In addition, patients presenting with ED should be screened for coronary artery disease risk factors, as the two conditions are highly associated.

Li et al. performed a prospective cohort study to determine whether sildenafil use is associated with increased rates of melanoma. They find a hazard ratio of 1.84 for the association, but note that the lower end of the 95% confidence interval is 1.04. They conclude that there may be a positive relationship between sildenafil and melanoma, however more studies are needed to determine whether this finding should be considered in the clinical sending.

Illustration A shows a snap gauge for measurement of penile tumescence. The gauge is placed around the penile shaft before sleeping, and penile tumescence causes the ring to open. Illustration B shows a strain gauge for measurement of penile tumescence. The gauge is place around the penile shaft at night and is connected to a pressure-monitor to evaluate for dilation of the shaft.

Incorrect Answers:
Answer 1: Since this patient is not considering fertility, a sperm sample is not warranted.
Answer 3: Duplex penile ultrasound is used to evaluate blood flow, venous leakage, atherosclerosis, and calcification in penile blood vessels.
Answers 4-5: Sildenafil and vardenafil are phosphodiesterase-5 inhibitors that aid in penile vasodilation.