Male Sexual Dysfunction and Male Infertility
Core concepts
This domain rewards structured evaluation more than memorised lists.
Erectile dysfunction: distinguish psychogenic from organic; know that ED is a marker of cardiovascular disease and that a man presenting with ED should be assessed for vascular risk. Understand the phosphodiesterase-5 inhibitor class, the absolute contraindication with nitrates, and the fact that PDE5 inhibitors require sexual stimulation. Second-line options include vacuum devices, intracavernosal injections and surgery. Trap: prescribing a PDE5 inhibitor to a man on nitrates, or attributing ED to age alone.
Ejaculatory dysfunction: premature ejaculation, delayed ejaculation, retrograde ejaculation (post-prostatectomy, diabetic autonomic neuropathy, alpha-blockers).
Infertility: the evaluation is of the couple, not just the man. Know semen analysis parameters (volume, concentration, motility, morphology) and the definitions of oligospermia, azoospermia and asthenospermia. Distinguish obstructive from non-obstructive azoospermia using FSH, testicular volume and post-ejaculate urinalysis. Know that Klinefelter syndrome, Y-chromosome microdeletions, and hypogonadotropic hypogonadism are examinable causes. Varicocele repair is the commonest correctable cause.
Genetics and counselling: men with severe oligospermia or azoospermia should be offered karyotype and Y-microdeletion testing before assisted reproduction.
Worked rule of thumb
A man with azoospermia, small testes and high FSH: this is non-obstructive azoospermia - the trap answer is "vasectomy reversal" or "epididymovasostomy", which apply only to obstructive azoospermia with normal FSH and normal testicular volume.
Exam traps
- Missing the nitrate contraindication.
- Investigating only the man and not the couple.
- Confusing obstructive and non-obstructive azoospermia.
- Forgetting genetic testing before ICSI in severe male factor.