Infertilitas Pria

01Pathophysiology

Male infertility accounts for roughly 40-50% of all infertility cases and can originate from disruption at any level of the hypothalamic-pituitary-gonadal (HPG) axis or the reproductive tract itself.

Pre-testicular causes involve failure of the hypothalamus or pituitary to provide adequate gonadotropin stimulation. The hypothalamus secretes GnRH in a pulsatile fashion, which drives anterior pituitary release of LH and FSH. LH stimulates Leydig cells to produce testosterone, while FSH acts on Sertoli cells to support spermatogenesis. Any disruption to this axis, whether from a pituitary adenoma (notably prolactinoma), Kallmann syndrome (GnRH deficiency + anosmia), exogenous androgen use, or chronic opioid therapy, leads to hypogonadotropic hypogonadism. Without adequate LH and FSH drive, both testosterone production and sperm output decline. This is why patients on exogenous testosterone or anabolic steroids become infertile: exogenous androgens suppress GnRH through negative feedback, collapsing intratesticular testosterone to levels insufficient for spermatogenesis.

Testicular causes represent primary gonadal failure. The most common correctable testicular cause is varicocele, present in approximately 35-40% of men with primary infertility. The mechanism involves retrograde venous flow through the internal spermatic vein (predominantly left-sided due to the left gonadal vein draining into the left renal vein at a right angle), leading to elevated scrotal temperature, oxidative stress, and impaired spermatogenesis. Other testicular causes include Klinefelter syndrome (47,XXY), where seminiferous tubule dysgenesis leads to small, firm testes and azoospermia; cryptorchidism, where prolonged exposure of the gonad to core body temperature damages germ cells irreversibly; and gonadotoxic injury from chemotherapy (particularly alkylating agents like cyclophosphamide) or radiation. In primary testicular failure, the pituitary recognizes low testosterone and absent inhibin B feedback from Sertoli cells, resulting in elevated FSH and LH (hypergonadotropic hypogonadism). This hormonal pattern is the hallmark of irreversible spermatogenic failure.

Post-testicular causes involve obstruction or dysfunction of sperm transport. The classic example is congenital bilateral absence of the vas deferens (CBAVD), which is strongly associated with CFTR gene mutations and is considered a forme fruste of cystic fibrosis. These patients produce sperm normally (normal FSH, normal testicular volume) but have obstructive azoospermia because sperm cannot reach the ejaculate. Other post-testicular causes include prior vasectomy, epididymal obstruction from infection (Chlamydia, gonorrhea), and ejaculatory duct obstruction. Retrograde ejaculation (common in diabetic autonomic neuropathy or post-TURP) diverts semen into the bladder instead of antegrade through the urethra; post-ejaculatory urinalysis showing abundant sperm confirms this diagnosis.

02Classification and Clinical Manifestation

The clinical classification directly determines the hormonal profile you expect, which is the single most tested concept in exam vignettes. The critical reasoning chain is:

Azoospermia + elevated FSH = primary testicular failure (non-obstructive) = poor prognosis for natural conception.

Azoospermia + normal FSH + normal testicular volume = obstructive azoospermia = potentially correctable.

Azoospermia + low FSH/LH = hypogonadotropic hypogonadism = potentially reversible with gonadotropin therapy.

03Diagnostic Workup

Semen Analysis (WHO 2021, 6th Edition)

This is the best initial test for evaluating male infertility. Two specimens collected at least 7 days but no more than approximately 4 weeks apart are recommended to account for physiologic variation. The patient should abstain from ejaculation for 2-7 days before collection.

Terminology

Interpreting the semen analysis in context is what the exam tests. A low-volume azoospermic sample with normal FSH and absent vas deferens on exam points directly to CBAVD, not testicular failure. Conversely, azoospermia with markedly elevated FSH and bilateral small testes indicates non-obstructive azoospermia from primary testicular failure.

The hormonal panel is ordered after an abnormal semen analysis to categorize the etiology. The critical branching point is FSH level: elevated FSH reflects loss of negative feedback from inhibin B (produced by Sertoli cells), signaling that the seminiferous tubule compartment is damaged. Normal FSH in the setting of azoospermia suggests the testis is producing sperm but the sperm cannot exit, pointing to an obstructive cause.

For patients with severe oligospermia or non-obstructive azoospermia, genetic testing is indicated. Karyotype identifies Klinefelter syndrome, which accounts for roughly two-thirds of chromosomal causes of male infertility. Y-chromosome microdeletion testing identifies deletions in the AZF (azoospermia factor) region of the long arm of the Y chromosome. This is prognostically important: AZFa and AZFb complete deletions predict no sperm will be found even with surgical retrieval, making sperm donation the only path to biological offspring via the male partner. AZFc deletions carry a more favorable prognosis, with approximately 50-70% chance of sperm retrieval via micro-TESE.

04Management and Treatment

Varicocelectomy is the most commonly tested surgical intervention. The microsurgical subinguinal approach offers the best outcomes (improved semen parameters in approximately 60-70% of patients) with the lowest complication rate. Improvement in semen parameters typically takes 3-6 months post-operatively, which corresponds to the duration of a full spermatogenic cycle (approximately 74 days for spermatogenesis + 12-14 days for epididymal transit). The exam tests the indication: a varicocele must be clinically palpable (not merely found on ultrasound) and associated with abnormal semen parameters in a couple with documented infertility.

For hypogonadotropic hypogonadism, the single most important concept is: never give exogenous testosterone to a man who wants fertility. Exogenous testosterone shuts down the HPG axis, collapses intratesticular testosterone (which needs to be 50-100x higher than serum levels to support spermatogenesis), and drives sperm counts to zero. The correct approach is hCG (which mimics LH and stimulates Leydig cells to produce endogenous intratesticular testosterone) with or without recombinant FSH (which directly stimulates Sertoli cells). This distinction between "testosterone for hypogonadism" and "gonadotropins for fertility" is a heavily tested concept.

Clomiphene citrate functions as a selective estrogen receptor modulator (SERM) at the hypothalamus and pituitary. By blocking estrogen-mediated negative feedback, it increases GnRH pulsatility, which raises endogenous LH and FSH secretion, thereby boosting both testosterone and sperm production. It is used off-label for idiopathic male infertility and as a bridge therapy when discontinuing exogenous androgens.

When medical and surgical options are exhausted, assisted reproductive technology becomes the pathway. IUI (intrauterine insemination) is appropriate for mild oligospermia or ejaculatory dysfunction when total motile sperm count after processing exceeds approximately 5-10 million. IVF is indicated for moderate male factor. ICSI (intracytoplasmic sperm injection) is the treatment for severe oligospermia, obstructive azoospermia (using surgically retrieved sperm), or non-obstructive azoospermia (using sperm from micro-TESE). ICSI requires only a single viable sperm per oocyte.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The most common way students lose points on male infertility questions is by failing to recognize the hormonal pattern that distinguishes the three etiologic categories. The exam will give you a man with azoospermia and expect you to determine the cause based on FSH, LH, and testosterone levels, not the semen analysis alone. A student who sees "azoospermia" and immediately jumps to "testicular failure" without checking whether FSH is normal (suggesting obstruction) or low (suggesting hypogonadotropic hypogonadism) will select the wrong answer.

The second major trap involves exogenous testosterone and fertility. The vignette may describe a man on testosterone replacement therapy for hypogonadism who now presents with infertility. The wrong answer will be "increase testosterone dose." The correct answer is to discontinue testosterone and initiate hCG with or without FSH to restore spermatogenesis. This tests whether the student understands that exogenous testosterone suppresses the HPG axis and eliminates intratesticular testosterone production.

A third tested concept is the CBAVD-CFTR connection. When the exam describes a man with azoospermia, low semen volume, and bilaterally absent vas deferens on examination, the expected next step is CFTR mutation testing, not a testicular biopsy. The partner must also undergo CFTR screening before proceeding with assisted reproduction, because if both partners carry CFTR mutations, the offspring is at risk for cystic fibrosis.

Finally, students frequently confuse when to order genetic testing. Karyotype and Y-chromosome microdeletion analysis are indicated for non-obstructive azoospermia or severe oligospermia (typically < 5 million/mL), not for mild oligospermia or isolated motility defects. The practical implication of Y-microdeletion testing is prognostic: identifying an AZFa or AZFb deletion changes counseling because surgical sperm retrieval is expected to fail, sparing the patient an unnecessary procedure.

The core competency being tested across all male infertility questions is the ability to integrate the semen analysis with the hormonal profile and physical examination to localize the defect, determine reversibility, and select the appropriate intervention. The exam rewards systematic reasoning through the HPG axis, not memorization of isolated facts.