Can an infection cause asymptomatic testicular atrophy?

Can Infection Cause Asymptomatic Testicular Atrophy?

Yes, infections can definitively cause asymptomatic testicular atrophy, with mumps orchitis being the most well-documented culprit, though many sexually transmitted infections and other inflammatory processes can also lead to silent testicular damage without overt symptoms.

Primary Infectious Causes

Mumps Orchitis

• Mumps orchitis represents the most common complication of mumps infection in men, occurring in 5-37% of cases, with bilateral involvement in 16-65% of affected patients 1.
• Testicular atrophy develops as a direct consequence of mumps orchitis, with ultrasonographic evidence showing affected testes becoming 23-55% smaller in volume (mean 44.7% reduction) compared to normal contralateral testes 2.
• The time course from acute mumps orchitis to documented testicular atrophy ranges from 25 to 230 days (mean 95.9 days), indicating this can be a delayed and potentially asymptomatic process 2.
• Atrophic testes after mumps orchitis characteristically exhibit an oblong shape, heterogeneous low echogenicity with multiple hyperechoic islands, and decreased vascularity on ultrasound 2.

Sexually Transmitted Infections

• Chlamydial and gonococcal infections are frequently asymptomatic in men (68-92% of men with gonorrhea and 92% with chlamydia report no symptoms), yet these infections can cause epididymitis and orchitis that may lead to testicular damage 3.
• Among heterosexual men, the number with asymptomatic chlamydial infections substantially exceeds those with symptomatic gonorrhea, creating a reservoir of untreated infection that can progress to complications 3.
• Chlamydial infections among men account for 30-40% of nongonococcal urethritis cases and 50% of epididymitis cases, conditions that can extend to testicular involvement 3.

Chronic Asymptomatic Orchitis

• Systematic histopathological analyses demonstrate a high prevalence of asymptomatic inflammatory reactions in testicular biopsies from infertile men, with mostly focal lymphocytic infiltrates correlating with the degree of spermatogenic damage 4.
• These chronic asymptomatic inflammations of the testicles are underestimated as a primary cause or cofactor of male fertility disorders because noninvasive diagnostic techniques are not yet available 4.
• Irreversible damage to spermatogenesis and corresponding decline in ejaculate quality are expected, particularly in cases of chronic orchitis, even when clinical symptoms are absent 4.

Clinical Implications and Screening

Detection Challenges

• Most studies of STDs are conducted in healthcare settings for symptomatic patients, which overestimates the proportion of infected persons who are symptomatic 3.
• Screening in non-healthcare settings (jails, workplaces, communities) reveals that most persons with gonorrhea or chlamydia are asymptomatic, with 52% of women with gonorrhea and at least 70% with chlamydia showing neither symptoms nor signs 3.
• Asymptomatic infected men may unknowingly harbor infections before seeking treatment, allowing progression to complications including testicular damage 3.

Risk Factors and Populations

• Rectal infections from sexually transmitted pathogens are generally asymptomatic but represent a common site of initial infection, particularly in men who engage in receptive anal intercourse 3.
• Infections at extragenital sites (pharynx and rectum) are typically asymptomatic yet can serve as reservoirs for ongoing transmission and potential systemic complications 3.

Diagnostic Approach

When to Suspect Infectious Testicular Atrophy

• Evaluate any patient with unexplained infertility or subfertility for history of mumps, sexually transmitted infections, or scrotal trauma 1, 2.
• Ultrasound with Doppler should assess testicular volume, shape, echogenicity, and vascularity, looking specifically for volume reduction, oblong shape, heterogeneous echogenicity, and decreased blood flow 2.
• Consider testicular biopsy in cases of unexplained infertility, as focal lymphocytic infiltrates may be present without clinical symptoms 4.

Screening Recommendations

• Screen sexually active men at risk for STDs even in the absence of symptoms, as early detection and treatment prevents complications including potential testicular damage 3.
• Opportunities to identify asymptomatically infected persons include screening during routine physical examinations, vaccination visits, and in non-healthcare settings 3.

Prevention Strategies

Early Treatment

• Early detection and treatment of curable STDs should be a central component of prevention strategies, as treating infections before complications develop prevents testicular damage 3.
• Any activity that decreases the incidence and prevalence of STDs in a population will decrease this key cofactor for testicular complications 3.
• For mumps orchitis specifically, some evidence suggests interferon-alpha-2B treatment (3 x 10^6 IU per day for 7 days) may prevent testicular atrophy, though results are mixed 1, 5.

Partner Management

• Sexual partners of patients with accessory sex gland infections known or suspected to be caused by sexually transmitted diseases must be referred for evaluation and treatment 3.
• Expedited partner therapy should be considered to prevent reinfection cycles that could lead to chronic inflammation 3.

Critical Pitfalls

• Never assume absence of symptoms means absence of infection or testicular damage—asymptomatic infections are the rule rather than the exception for many STDs 3.
• Do not overlook mumps history in patients with unexplained testicular atrophy or infertility, as the connection may not be immediately apparent months after acute infection 2.
• Avoid dismissing subtle testicular volume differences on examination, as even modest reductions may indicate significant underlying pathology 2.
• Recognize that chronic asymptomatic orchitis is likely underdiagnosed due to lack of noninvasive diagnostic techniques, making it a hidden contributor to male infertility 4.