Inflammation of the testis (orchitis) and the epididymis (epididymitis) frequently coexist as epididymo-orchitis. The single most important step in any acutely painful scrotum — especially in a younger patient — is to rule out testicular torsion before settling on an inflammatory diagnosis.
Orchitis
Orchitis is inflammation of the testis (the term is sometimes misapplied to testicular pain without objective inflammation). Acute orchitis is the sudden onset of pain and swelling with acute inflammation; chronic orchitis is inflammation and pain, usually without swelling, persisting >6 weeks.
Classification:
- Acute bacterial — secondary to UTI or STI.
- Non-bacterial infectious — viral (the most common viral cause is mumps), fungal, parasitic, rickettsial.
- Non-infectious — idiopathic, traumatic, autoimmune.
- Chronic orchitis / chronic orchialgia — often clinically indistinguishable from each other.
Pathogenesis — bacterial orchitis usually accompanies epididymitis (local spread from the ipsilateral epididymis). In boys and elderly men, UTIs (E. coli, Pseudomonas) are the usual source; in young sexually active men, STIs are often responsible. Isolated orchitis without epididymitis is rare and usually viral (haematogenous spread); mycobacterial infection, TB, and BCG therapy can also cause it. It is usually unilateral but may be bilateral, especially when viral.
Diagnosis and evaluation:
- Acute infectious orchitis — recent testicular pain, often with abdominal discomfort, nausea, and vomiting, possibly preceded by parotitis (boys/young men), UTI (boys/elderly), or STI symptoms; the patient may appear toxic and febrile.
- Acute non-infectious orchitis — similar but without the toxic appearance or fever; in a young patient the key differential is testicular torsion.
- Chronic orchitis/orchialgia — often prior episodes; the scrotum is usually non-erythematous but the testis is indurated and tender.
- Labs — urinalysis, microscopy, and culture; a urethral swab if an STI is suspected. Imaging — scrotal ultrasound if the diagnosis is unclear (and to exclude malignancy in chronic orchitis/orchialgia).
Management — general measures are bed rest, scrotal support, hydration, antipyretics, anti-inflammatories, and analgesics; chronic orchitis/orchialgia is managed supportively (anti-inflammatories, analgesics, heat, nerve blocks).
- Infectious orchitis gets targeted antibiotics (for the underlying UTI, prostatitis, or STI); if early tests are negative or unavailable, empirical therapy with a fluoroquinolone is the best choice.
- TB orchitis — antituberculous therapy (rifampin, isoniazid, and pyrazinamide or ethambutol), rarely surgery.
- Mumps orchitis — no specific antiviral; supportive care.
- Abscess is rare and needs percutaneous or open drainage. Spermatic-cord blocks with local anaesthetic may relieve severe pain. Surgery is rarely indicated unless torsion (or, rarely, xanthogranulomatous orchitis) is suspected; orchidectomy is reserved for pain refractory to all else (and may still not relieve it).
Epididymitis
Epididymitis is inflammation of the epididymis. Acute epididymitis is sudden pain and swelling lasting <6 weeks; chronic epididymitis is pain (usually without swelling, but with induration in long-standing cases) persisting >6 weeks. Chronic infectious epididymitis is most commonly tuberculous — from haematogenous spread rather than seeding from the kidneys.
Classification:
- Acute bacterial — secondary to UTI or STI.
- Non-bacterial infectious — viral, fungal, parasitic.
- Non-infectious — idiopathic, traumatic, autoimmune, amiodarone-induced, or syndrome-associated (e.g. Behçet disease).
- Chronic epididymitis / chronic epididymalgia.
Causes — acute epididymitis usually spreads from the bladder, urethra, or prostate along the ejaculatory ducts and vas deferens. The likely pathogen depends on the population:
| Population | Common pathogens |
|---|---|
| Children and elderly men | Uropathogens — E. coli most common (driven by BPH stasis, UTI, catheterisation) |
| Sexually active men <35 (sex with women) | N. gonorrhoeae and C. trachomatis |
| Men who have sex with men (anal intercourse) | E. coli and Pseudomonas |
Chronic epididymitis arises from inadequately treated or recurrent acute epididymitis, tuberculosis, amiodarone, or Behçet disease. Risk factors for recurrent epididymitis are meatal stenosis, urethral stricture, high-pressure voiding dysfunction, and ectopic ureter.
Diagnosis and evaluation — rule out testicular torsion, especially in younger patients. Examination localises tenderness to the epididymis (often with testicular involvement = epididymo-orchitis), and the spermatic cord is usually tender and swollen. Labs: midstream urine and Gram stain of a urethral smear. Imaging: scrotal ultrasound can help but is not always diagnostic.
Management — start empirical therapy before results return (anti-inflammatories, analgesics, scrotal support, nerve blocks). For acute bacterial epididymitis (EAU Guidelines on Urological Infections):
- Gonorrhoea likely: ceftriaxone 1000 mg IM/IV ×1 + doxycycline 200 mg PO once then 100 mg BID for 10–14 days.
- Gonorrhoea unlikely (no urethral discharge): doxycycline 200 mg then 100 mg BID for 10–14 days plus an agent active against Enterobacterales for 10–14 days.
- Non-sexually active: an oral fluoroquinolone (levofloxacin) daily for 10–14 days.
For chronic epididymitis, a 4–6 week antibiotic trial covering likely pathogens — particularly C. trachomatis — may be appropriate. Epididymectomy is considered only after all conservative measures are exhausted, and only once the patient accepts that it has at best a 50% chance of curing the pain.
Self-Test
1. What organisms cause epididymitis, and how is it treated? Organisms by population: children and elderly men — uropathogens, especially E. coli (from BPH stasis, UTI, catheterisation); sexually active men <35 who have sex with women — N. gonorrhoeae and C. trachomatis; MSM — E. coli and Pseudomonas; chronic infectious epididymitis — tuberculosis. Treatment (EAU): if gonorrhoea is likely, ceftriaxone 1 g IM/IV once plus doxycycline 100 mg BID for 10–14 days; if unlikely, doxycycline plus an anti-Enterobacterales agent for 10–14 days; if non-sexually active, levofloxacin for 10–14 days; for chronic disease, a 4–6 week antibiotic trial covering C. trachomatis.