• Inflammation of testis - can be infectious (usually) or non-infectious
  • Infectious
    • Viral - most common etiology is mumps (orchitis seen in 20-30% of mumps patients)[1]
      • Epididymis typically not involved
    • Bacterial - typically due to hematogenous spread from epididymis: "epididymo-orchitis"
      • (bacterial infections rarely involve only the testis)
      • bacterial pathogens: N. gonorrhea, C. trachomatis, E. Coli, Klebsiella, P. aeruginosa

Clinical Features

  • Testicular tenderness, edema
  • May see erythema of overlying scrotum
  • Viral orchitis
    • Abrupt onset of scrotal pain/swelling 4-7 days after onset of parotitis[1]
    • Usually unilateral
  • Fever, tachycardia
  • Inguinal lymphadenopathy
  • Patient uncomfortable while seated

Differential Diagnosis

Testicular Diagnoses



  • Testicular ultrasound
  • Urinalysis and urine culture
  • May also consider GC, Chlamydia cultures


  • Combination of clinical features and results of imaging/UA
  • Ultraound may show inflammation, epididymitis, and rules out active torsion
  • Urinalysis positive for infection in epididymo-orchitis



  • Generally may be discharged home

See Also


  1. 1.0 1.1 Trojian, Thomas H., Timothy S. Lishnak, and Diana Heiman. "Epididymitis and orchitis: an overview." Am Fam Physician 79.7 (2009): 583-587.