The patient’s presentation is consistent with acute epididymitis. In patients older than 35 years (as well as younger than 14), the most common organism is E. coli or other gram negative rods.
Epididymitis is the most common cause of scrotal pain in adults males. It is typically caused by a bacterial retrograde infection. Risk factors for the development of epididymitis include sexual activity, strenuous physical activity, bicycling, and prolonged periods of sitting. Symptoms usually include a gradual onset of scrotal pain with swelling, possible urinary tract symptoms, and fever.
Trojian et al. discuss epididymitis and orchitis diagnosis and management, as well as the differential for scrotal pain. They stress the importance of distinguishing epididymitis from testicular torsion, which is often a surgical emergency. Doppler ultrasonography can be an important diagnostic tool in addition to history and physical in distinguishing these diagnoses. Besides antibiotics, symptom relief for epididymitis includes analgesics, scrotal elevation, limitation of activity, and use of cold packs.
Tracy et al. discuss possible causes of noninfectious epididymitis, which include sarcoidosis, Behcet's disease, Henoch-Schonlein purpura, and medication-induced (e.g. amiodarone). Diagnostic testing for infectious epididymitis also can include a gram stain of urethral exudate, PCR for chlamydia, and direct fluorescent antibody testing.
Illustration A displays the anatomy of the epididymis relative to the testicle.
Answers 1,2: N. gonorrheae and C. trachomatis are the most common pathogens in men 14-35 years of age.
Answers 3,4: There are not common infectious agents in epididymitis.
Trojian TH, Lishnak TS, Heiman D. Epididymitis and orchitis: an overview. Am Fam Physician. 2009 Apr 1;79(7):583-7.
PMID:19378875 (Link to Abstract)
Tracy CR, Steers WD, Costabile R. Diagnosis and management of epididymitis. Urol Clin North Am. 2008 Feb;35(1):101-8; vii.
PMID:18061028 (Link to Abstract)