What prior infections can cause testicular atrophy?

Prior Infections That Can Cause Testicular Atrophy

Mumps orchitis is the most well-documented infectious cause of testicular atrophy, occurring in 5-37% of postpubertal males with mumps infection, with bilateral involvement in 16-65% of cases leading to significant risk of sterility. 1, 2

Primary Infectious Causes

Mumps Orchitis

• Mumps virus represents the most common and clinically significant infectious cause of testicular atrophy, particularly affecting unvaccinated postpubertal males 2
• Testicular atrophy develops in a substantial proportion of cases, with ultrasonographic evidence showing affected testes becoming 23-55% smaller in volume (mean 44.7% reduction) compared to contralateral normal testes 3
• The time course from acute mumps orchitis to documented testicular atrophy ranges from 25-230 days (mean 95.9 days) 3
• Characteristic ultrasonographic findings of atrophic testes include oblong shape, heterogeneous hypoechogenicity with multiple hyperechoic islands, and decreased vascularity 3
• The condition can result in permanent subfertility or infertility, with historical data showing gynecomastia developing 1-30 years after testicular atrophy due to impaired Leydig cell testosterone secretion 4

Bacterial Epididymo-orchitis

• Untreated or inadequately treated bacterial epididymitis can progress to involve the testis (epididymo-orchitis) and potentially cause testicular atrophy 5
• The predominant bacterial pathogens include Chlamydia trachomatis, Neisseria gonorrhoeae, and Enterobacterales, with pathogen distribution varying by age and sexual activity 5
• In up to 90% of acute epididymitis cases, pathogens migrate from the urethra or bladder 5
• Complications of untreated chlamydial infection specifically include chronic pain and potential infertility 5

Genitourinary Tuberculosis (GUTB)

• Tuberculosis can manifest as genitourinary disease and affect testicular tissue, though it is often underestimated in non-endemic regions 5
• GUTB represented 4.6% of extrapulmonary tuberculosis cases and should be considered in the differential diagnosis of chronic testicular pathology 5

Secondary Infectious Considerations

Fournier's Gangrene

• This aggressive polymicrobial necrotizing soft tissue infection involves the scrotum and external genitalia 5
• While the testes and spermatic cord are typically spared due to separate blood supply, extensive infection can lead to testicular damage 5
• The gangrene is usually limited to skin and subcutaneous tissue, but severe cases with delayed treatment may compromise testicular viability 5

Other Sexually Transmitted Infections

• Persistent or recurrent gonococcal and chlamydial urethritis can ascend to cause epididymo-orchitis if untreated 5
• Mycoplasma genitalium and Ureaplasma urealyticum have been implicated in nongonococcal urethritis that can progress to epididymitis 5

Clinical Recognition and Prevention

Key Diagnostic Features

• Acute orchitis presents with pain, swelling, and elevated temperature of the epididymis and testis 5
• Ultrasonography with Doppler is the first-line imaging modality, showing increased blood flow in acute infection and decreased vascularity in chronic atrophic changes 3
• Follow-up imaging at 3-6 months after acute orchitis is essential to detect developing atrophy 3

Critical Management Points

• Empiric antimicrobial therapy for bacterial epididymo-orchitis must be initiated promptly with ceftriaxone 1g IM/IV plus azithromycin 1g PO for gonococcal infection, or doxycycline 100mg twice daily for 7 days for non-gonococcal infection 5
• Failure to improve within 3 days requires reevaluation, with differential diagnosis including abscess, infarction, testicular cancer, tuberculosis, and fungal epididymitis 5
• Bed rest, scrotal elevation, and analgesics are recommended adjuncts until fever and inflammation subside 5

Long-term Sequelae

• Testosterone replacement therapy may be indicated for primary hypogonadism resulting from bilateral testicular failure due to orchitis 6, 7
• The FDA labels for testosterone cypionate and enanthate specifically list orchitis as a cause of primary hypogonadism requiring replacement therapy 6, 7

Prevention Strategies

• MMR vaccination remains the most effective prevention for mumps orchitis, with recent outbreaks attributed to reduced vaccine uptake in the 1990s 2
• Prompt treatment of urethritis and sexually transmitted infections prevents ascending infection and subsequent testicular complications 5
• Partner notification and treatment are essential to prevent reinfection and complications 5