Penile hemodynamics in hypogonadal men with micropenis

Objectives. To document the penile vascular and erectile response to intracavernous injection (ICI) of vasoactive agent in hypogonadal men with micropenis. Methods. A total of 15, previously untreated, hypogonadal men with micropenis (stretched penis length less than 2.5 SD below the mean of the normal population) underwent a detailed urologic and endocrinologic evaluation. Their mean age was 21.2 ± 4.2 years. Penile hemodynamics were assessed by color Doppler ultrasonography before and after ICI of 5 μg of prostaglandin E₁ combined with manual genital self-stimulation. Results. Endocrinologic evaluation revealed that hypogonadism was hypogonadotropic in 10 (66.7%) and hypergonadotropic in 5 (33.3%). Karyotype analysis showed 46XY in all. Their mean stretched penile length was 6.2 ± 1.4 cm (range 3 to 7.5) and increased to a mean of 6.96 ± 1.5 cm (range 4 to 8.5) after ICI. The serum free testosterone levels ranged from 0.2 to 3.2 pg/mL (mean 1.9 ± 0.92). None had had any previous sexual experience, and 14 (93.3%) reported a history of nocturnal erections. Penile color Doppler ultrasonography demonstrated a normal penile vascular system in 7 (46.7%) and penile arterial insufficiency in 4 (28.6%). All 11 of these patients (73.3%) achieved an adequate erectile response to ICI combined with manual stimulation. Mixed vascular disease was observed in the remaining 4 patients (28.8%), and they did not have a sufficient erectile response to ICI. Color Doppler ultrasonography revealed similar results in the hypogonadotropic and hypergonadotropic men. Conclusions. Our data suggest that the erectile response to ICI combined with manual genital self-stimulation is effective in most hypogonadal men having a micropenis with low serum androgen levels.