Orchitis

Orchitis is clinically relevant as an acute inflammatory condition of the testis that can cause significant pain, scrotal swelling, and fever^1,2,3. It often presents suddenly and requires prompt medical attention to differentiate from other causes of acute scrotal pain, such as testicular torsion, which is a surgical emergency^1,2.

Relevant Medical Conditions & Etiology:

Orchitis can be caused by various infectious agents:

• Viral Infections: The most common viral cause is the mumps virus, particularly in unvaccinated post-pubertal males. Mumps orchitis typically develops 4 to 7 days after the onset of parotitis (inflammation of the salivary glands)^1,2.
• Bacterial Infections: Bacterial orchitis is often associated with epididymitis (epididymo-orchitis). The infection usually ascends from the lower urinary tract (e.g., urethritis, cystitis, prostatitis) or is a result of sexually transmitted infections (STIs)^1,2,3. Common bacterial pathogens include Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus, and Streptococcus species in older men or those with urinary tract abnormalities¹. In sexually active younger men (typically <35 years), Chlamydia trachomatis and Neisseria gonorrhoeae are common causes^1,2.
• Other Infections: Less commonly, other viruses (e.g., coxsackievirus, varicella, echovirus, cytomegalovirus) or bacteria (Mycobacterium avium complex, Cryptococcus neoformans, Toxoplasma gondii, Haemophilus parainfluenzae, Candida albicans) can cause orchitis, especially in immunocompromised individuals¹.
• Autoimmune Orchitis: In some cases, orchitis can have an autoimmune etiology⁴.

Risk Factors:

Risk factors for developing orchitis include^1,2:

• Lack of mumps vaccination.
• Age (mumps orchitis is more common after puberty; bacterial orchitis from non-STI pathogens is more common in older men or those with benign prostatic hyperplasia).
• High-risk sexual behaviors (multiple partners, sex without a condom, history of STIs) for STI-related orchitis.
• Recent urinary tract instrumentation or catheterization.
• Anatomical abnormalities of the urinary tract (e.g., urethral stricture, bladder outlet obstruction).
• Previous history of epididymitis.

Diagnostic Procedures and Treatment Approaches:

• Diagnosis: Diagnosis is primarily based on clinical history and physical examination findings, which typically include testicular tenderness, enlargement, induration, and scrotal edema or erythema¹.
  • Urinalysis and urine culture may be performed to identify bacterial pathogens¹.
  • Urethral swabs for STI testing (N. gonorrhoeae and C. trachomatis) are recommended in sexually active individuals¹.
  • Color Doppler ultrasonography is the imaging modality of choice to assess blood flow (ruling out testicular torsion, which shows absent or reduced flow) and evaluate for complications like abscess formation. In orchitis, ultrasound typically shows increased testicular blood flow^1,7.
  • Serum immunofluorescence antibody testing can confirm mumps orchitis, though not typically done routinely¹.
• Treatment: Treatment depends on the underlying cause^1,2,3:
  • Bacterial Orchitis: Antibiotics are prescribed based on the likely pathogens and patient\s age/sexual history. For STIs, ceftriaxone plus doxycycline or azithromycin is common. For enteric organisms, fluoroquinolones (e.g., ciprofloxacin, levofloxacin) or trimethoprim-sulfamethoxazole are options. Sexual partners of patients with STI-induced orchitis should also be treated^1,3.
  • Viral Orchitis (e.g., Mumps): Treatment is supportive as antibiotics are not effective. This includes bed rest, scrotal support (e.g., jockstrap), ice packs to the scrotum, and analgesics/anti-inflammatory medications (e.g., NSAIDs) for pain and fever management^1,2,3.
  • General Supportive Measures: Regardless of the cause, supportive care includes pain relief, scrotal elevation, and rest^1,2,3.
  • Hospitalization may be required for severe cases, signs of sepsis, inability to take oral antibiotics, or if surgical intervention is needed for complications like an abscess¹.

Expected Outcomes and Recovery:

• Most cases of orchitis, both viral and antibiotic-treated bacterial cases, resolve without long-term complications, especially if treated promptly^1,2.
• Pain and swelling usually begin to improve within a few days of starting appropriate treatment, but complete resolution of tenderness and swelling can take several weeks or even months^1,2,3.
• A decrease in body temperature within the first three days of antibacterial treatment is a good prognostic marker for bacterial orchitis¹.

Complications:

While most patients recover fully, potential complications of orchitis include^1,2,3:

• Testicular Atrophy: Shrinkage of the affected testicle. This is a significant concern, especially with mumps orchitis occurring after puberty, where up to 60% of cases may show some degree of atrophy¹.
• Impaired Fertility/Sterility: This is a rare complication, particularly if only one testicle is affected. Bilateral orchitis carries a higher risk^1,2.
• Scrotal Abscess: Collection of pus within the scrotum, which may require surgical drainage¹.
• Reactive Hydrocele: Fluid collection around the testicle¹.
• Chronic Epididymitis or Orchialgia: Persistent pain.
• Hypogonadism: Reduced testosterone production (rare)².