Varicocele — Causes, Semen Analysis, Varicocelectomy & Male Fertility Guide — Symptoms, Causes & Treatment | MyMedicPlus

A varicocele is an abnormal enlargement and tortuosity of the pampiniform venous plexus surrounding the spermatic cord within the scrotum, analogous to varicose veins in the legs. It results from retrograde blood flow (reflux) in the internal spermatic vein due to incompetent or absent venous valves. Varicoceles are present in approximately 15% of all adult men, rising to 40% of men investigated for primary infertility and up to 80% of those with secondary infertility (previously able to father children). Left-sided varicoceles account for 90% of cases due to the perpendicular (90°) drainage angle of the left spermatic vein into the left renal vein; right-sided or bilateral are less common. Varicoceles impair testicular function — raising intrascrotal temperature, impairing sperm production, maturation, and motility — and are the most common correctable cause of male factor infertility worldwide.

The primary cause of varicocele is valvular incompetence or congenital absence of valves in the internal spermatic vein, allowing retrograde blood flow. This results in venous pooling and dilation of the pampiniform plexus. Why the left side is more commonly affected: the left internal spermatic vein drains at a right angle into the left renal vein (creating a longer column of blood and higher hydrostatic pressure), whereas the right spermatic vein drains at an oblique angle directly into the inferior vena cava. The elevated venous pressure impairs testicular thermoregulation — venous stasis increases intrascrotal temperature, inhibiting spermatogenesis, reducing testosterone secretion from Leydig cells, and promoting oxidative stress and DNA damage in sperm. Secondary varicocele (rare but important): due to extrinsic compression of the left renal vein or inferior vena cava — causes include retroperitoneal lymphadenopathy, renal cell carcinoma ('nutcracker' tumour thrombus), retroperitoneal fibrosis, and aortic aneurysm. A new right-sided varicocele in an adult man should always raise suspicion of underlying pathology.

Most varicoceles are asymptomatic and discovered incidentally during fertility investigations or routine examination. Symptoms when present: dull, aching, or dragging scrotal pain or heaviness — typically left-sided, worsening after prolonged standing, physical exertion, or toward the end of the day, and relieved by lying down. Scrotal swelling or visible tortuous veins ('bag of worms' appearance on inspection and palpation). Testicular atrophy (reduction in testicular size — measured by Prader orchidometer): ipsilateral testicular hypotrophy is a key clinical finding indicating significant testicular damage — a size discrepancy above 20% between testes is clinically significant. Infertility: couples presenting with male factor infertility should be investigated for varicocele — abnormal semen parameters (reduced sperm count, motility, and morphology — oligospermia, asthenospermia, teratospermia). Clinical grading (Dubin and Amelar): Grade I — palpable only on Valsalva manoeuvre; Grade II — palpable without Valsalva; Grade III — visible ('bag of worms') without palpation.

Clinical examination: performed with the patient standing in a warm room to maximise venous dilation. Visual inspection for visible varicosities; palpation of the spermatic cord for tortuous veins with and without Valsalva manoeuvre; testicular volume measurement with a Prader orchidometer. Scrotal colour Doppler ultrasound: the standard imaging modality — detects venous diameter above 3 mm and retrograde blood flow on Valsalva; assesses testicular echogenicity and volume; essential for subclinical varicoceles. Semen analysis (two samples, 2–3 days abstinence, processed within 1 hour): WHO 2021 lower reference limits — sperm concentration above 16 million/mL; total motility above 42%; progressive motility above 30%; normal morphology above 4% (Kruger strict criteria); total sperm count above 39 million per ejaculate. Additional investigations for infertility: FSH, LH, testosterone, prolactin; karyotype (if sperm concentration below 5 million/mL — exclude Klinefelter); Y chromosome microdeletion analysis (AZF regions); anti-sperm antibodies. CT abdomen/pelvis or MRI: indicated when secondary varicocele is suspected (right-sided, new-onset in adult).

Indications for treatment: varicocele with abnormal semen parameters in a couple with infertility; varicocele with testicular hypotrophy (especially in adolescents); significant symptomatic pain failing conservative measures; bilateral clinical varicoceles. Observation: appropriate for adolescents with normal testicular symmetry, men in fertile relationships with normal semen analysis, and subclinical varicoceles. Microsurgical subinguinal or inguinal varicocelectomy (gold standard): performed under magnification; ligation of all dilated veins while preserving the testicular artery and lymphatics; lowest recurrence rate (below 5%); improves sperm parameters in 60–70% of men; spontaneous pregnancy rates of 30–60% post-surgery. Laparoscopic varicocelectomy: alternative surgical approach. Percutaneous embolisation (radiological): catheter-based occlusion of the internal spermatic vein using coils or sclerosant under local anaesthesia — minimally invasive, rapid recovery; higher recurrence rate than microsurgical approach; preferred in men with previous inguinal surgery. Assisted reproductive technology (ART): ICSI is an alternative in couples with multiple infertility factors or where female age-related urgency exists — varicocelectomy may allow IVF/ICSI where previously sperm counts were insufficient.

Varicocele causes progressive testicular dysfunction if left untreated. The most clinically significant complication is infertility — varicocele is found in 35-40% of men investigated for infertility, and progressive spermatogenic damage from venous stasis, elevated scrotal temperature (1-2°C above normal body temperature), retrograde adrenal metabolites, and oxidative stress reduces sperm concentration, motility, and morphology over time. Adolescent varicocele is particularly important: untreated varicocele in adolescence causes ipsilateral testicular atrophy (reduced volume) in approximately 60-70% of affected boys — early varicocelectomy (correction) prevents long-term spermatogenic damage and is recommended when testicular atrophy or catch-up growth failure is documented. Testosterone deficiency — from Leydig cell dysfunction secondary to elevated testicular temperature and venous hypertension — is documented in men with grade 2-3 varicocele, with low total testosterone and elevated LH/FSH indicating compensated hypogonadism; surgical repair improves testosterone levels in 50-70% of cases. Chronic scrotal discomfort — a dull aching or dragging sensation worsening with prolonged standing or exertion — impairs quality of life and occupational function. Following varicocelectomy (microsurgical, laparoscopic, or percutaneous embolisation), complications include hydrocele formation (1-3%), recurrence (3-15% depending on technique), and rarely testicular atrophy from arterial injury.

Varicoceles cannot be prevented — they arise from congenital venous valve abnormalities. However, early detection allows intervention before irreversible testicular damage occurs. All male adolescents should be examined for varicocele during routine health checks. Adolescent varicocele: a varicocele associated with ipsilateral testicular hypotrophy above 20% should be treated promptly, as catch-up growth and preservation of fertility potential is more likely with early intervention. Lifestyle measures to reduce discomfort: scrotal support (athletic supporter or snug-fitting underwear) reduces venous pooling and pain during standing and physical activity; avoid prolonged standing. For men with varicocele and infertility concerns: avoidance of excessive testicular heat (hot baths, laptop use on lap — raises scrotal temperature); avoidance of anabolic steroids (suppress spermatogenesis); optimise general health (healthy BMI, balanced diet, reduced alcohol, no smoking).

See your GP or a urologist if you experience: persistent dull aching scrotal pain or testicular heaviness — particularly on the left side, worse on standing and relieved by lying down; visible or palpable tortuous veins in the scrotum ('bag of worms' appearance); or size discrepancy between the testes noticed on self-examination. Seek assessment if you and your partner have been trying to conceive without success for 12 months (6 months if female partner is over 35) — a varicocele investigation including scrotal Doppler and semen analysis is an essential first step. Adolescent boys with varicocele and a smaller left testis should be referred to a paediatric urologist promptly — early repair may preserve fertility. Seek urgent assessment for: sudden-onset severe scrotal pain (suspect testicular torsion — a surgical emergency); a hard lump within the testis (testicular cancer); or a new right-sided varicocele in an adult man (exclude retroperitoneal pathology with imaging).