Epididymitis

Epididymitis is inflammation of the epididymis — the coiled tube along the posterior aspect of each testis that stores and matures sperm — almost always caused by an ascending infection from the urethra or bladder, and often extending to involve the testis as well (epididymo-orchitis). Which organism is doing the ascending depends heavily on age and sexual behaviour: in sexually active men, especially those under about 35, Chlamydia trachomatis and Neisseria gonorrhoeae are the most common causes; in men older than about 35, or anyone with bladder outlet obstruction or recent urologic instrumentation, enteric organisms — chiefly Escherichia coli — reflux retrograde up the ejaculatory duct instead; and coliform organisms are also a frequent cause in sexually active men of any age who practice unprotected insertive anal intercourse, regardless of how young or otherwise low-risk they might otherwise appear for an enteric infection.^[1][2]

Once torsion has been confidently excluded, the rest of this chapter is a genuinely pharmacist-relevant stewardship problem: matching the empiric antibiotic regimen to the actual likely etiology by age and sexual history, rather than defaulting to one regimen for everyone, and following through on partner notification and treatment when an STI is the cause.

Pathophysiology and age/behaviour-stratified etiology

In the large majority of cases, epididymitis results from an ascending infection: organisms travel retrograde from the urethra, through the vas deferens, into the epididymis, triggering a local inflammatory response.^[2]

Clinical presentation

The classic presentation is the gradual onset of unilateral posterior scrotal pain and swelling over 1-2 days — this gradual timeline is itself a key differentiating feature from the sudden, severe onset of testicular torsion (see below). Associated features often include dysuria, urethral discharge, urinary frequency, fever, and pain that can radiate to the lower abdomen or flank; hematuria is also reported.^[2] On examination, tenderness and swelling localize initially to the epididymis — posterior and slightly separate from the testis itself — before often becoming difficult to distinguish from the testis as swelling progresses; a reactive hydrocele and scrotal skin erythema/warmth can accompany more advanced cases.^[2]

The critical differential: testicular torsion

Torsion of the spermatic cord is most common in adolescents and young men, frequently related to an anatomic predisposition (the "bell-clapper deformity," a high attachment of the tunica vaginalis that leaves the testis abnormally mobile — present bilaterally in roughly 40% of affected patients).^[3] Unlike epididymitis, torsion presents with abrupt, severe, often constant pain, frequently with nausea and vomiting, and physical findings that point the other way: a high-riding testicle with a horizontal (transverse) rather than vertical lie, scrotal swelling and erythema, and an absent cremasteric reflex — a materially more reliable finding than commonly taught, associated with an odds ratio of 7.8 for torsion when absent.^[2] Prehn's sign — pain relief with scrotal elevation, classically taught as reassuring for epididymitis — is explicitly called out in current sources as unreliable for this purpose and must never be used to rule out torsion in an equivocal case.^[3][2]

^[2][3]

A related, benign mimic: torsion of the appendix testis

A small vestigial appendage at the upper pole of the testis can itself torse, producing a more localized, often milder pain; a classic (though not universally present) finding is the "blue dot sign" — a tender, cyanotic nodule visible through the scrotal skin at the upper pole. This is a benign, self-limited condition that does not require surgery — but it is a diagnosis of exclusion made after torsion of the testis itself and epididymitis have both been genuinely considered, not assumed on first impression.^[3]

• Sexually active, age under about 35, unprotected intercourse, or a new sexual partner — the population in whom chlamydia and gonorrhea are the leading causes.^[1][2]
• Unprotected insertive anal intercourse — raises the likelihood of enteric-organism epididymitis at any age, independent of the other STI risk factors above.^[1][2]
• Age over about 35, benign prostatic hyperplasia, or another cause of bladder outlet obstruction — the population in whom retrograde urinary reflux introduces enteric organisms instead of an STI pathogen.^[2]
• Recent urologic instrumentation or catheterization — a plausible, though inconsistently documented, contributing factor; some series report epididymitis appearing weeks to months after the procedure.^[2]
• An anatomic urinary tract abnormality in a prepubertal boy — the population in whom epididymitis is least likely to be a straightforward ascending bacterial infection and most likely to need urology referral (see Special Populations).^[2]
• HIV infection or another cause of significant immunocompromise — broadens the causative organism list to include cytomegalovirus, Salmonella, Ureaplasma urealyticum, and mycobacteria.^[2]
• Amiodarone use — a distinct, dose-related, non-infectious cause that will not respond to antibiotics.^[2]
• An anatomic predisposition to testicular torsion itself (the bell-clapper deformity) is not a risk factor for epididymitis, but is exactly why any acute scrotal presentation in an adolescent or young man needs torsion actively excluded rather than assumed away based on age or gradual timeline alone.^[3]

Complications

• Testicular infarction/loss from missed or delayed-diagnosis torsion — irreversible once ischemic time is exceeded, and the single most severe complication in this entire chapter.^[3]
• Scrotal abscess — suspect with fluctuance, a rapidly enlarging or poorly defined mass, or failure to improve on appropriate antibiotics; needs urologic evaluation and imaging, and often surgical drainage.^[2]
• Fournier's gangrene — a rare but life-threatening necrotizing soft-tissue infection of the perineum/genitalia; look for rapidly spreading erythema, crepitus, disproportionate pain, and systemic toxicity. This is a surgical emergency requiring immediate referral, not outpatient antibiotic escalation.
• Orchitis (spread of infection to the testis itself) is common with untreated or inadequately treated epididymitis and increases the risk of the complications below.^[2]
• Infertility and chronic scrotal pain are recognized long-term sequelae of inadequately treated or recurrent epididymitis/epididymo-orchitis, part of why prompt, correctly targeted treatment and full course completion genuinely matter.^[2]

History and examination

Characterize the onset (gradual versus sudden), and take a specific sexual history: new or multiple partners, condom use, and — critically — whether the patient practices insertive anal intercourse, since this single detail changes empiric antibiotic selection regardless of age (see Recognize the Condition). Ask about urinary symptoms, prior UTI, prostate disease, and any recent urologic instrumentation. On examination, assess testicular position and lie, test the cremasteric reflex, and specifically look for the features in the Recognize the Condition differential table before assuming epididymitis.

The TWIST score — a bedside torsion-risk aid, not a stand-alone diagnostic test

TWIST is a simple point-sum clinical score that helps stratify the urgency of imaging versus immediate surgical exploration in suspected torsion; it is presented here as a teaching reference, not an automated calculator.^[3]

• 0-2 points — low risk; torsion is less likely, but exam findings should still guide whether epididymitis workup proceeds.
• 3-4 points — intermediate risk; obtain urgent scrotal Doppler ultrasound.
• 5-7 points — high risk; proceed to emergent urologic consultation and consider surgical exploration without waiting for imaging.^[3]

Laboratory testing

• A urethral swab for Gram stain.^[1]
• Specimens for N. gonorrhoeae and C. trachomatis (intraurethral exudate or urine, per available laboratory technique) — in symptomatic men who have sex with men, or wherever the probability of treatment failure is elevated, collect specimens for gonorrhea by both culture and NAAT, not NAAT alone, since culture is what allows susceptibility testing.^[1]
• Microscopy and culture of a mid-stream urine sample in every patient.^[1]
• NAAT for gonorrhea and chlamydia specifically in sexually active men under about 35, or anyone with a new sex partner.^[2]
• An elevated CRP is a supportive, non-specific adjunct finding for an inflammatory/infectious process.^[2]

Imaging

Ultrasound is not required for every straightforward, classic presentation, but is indicated whenever torsion cannot be confidently excluded on history and exam, or when the diagnosis is otherwise unclear. Colour Doppler ultrasound shows increased flow/hyperemia in epididymitis, versus decreased or absent flow in torsion; reported sensitivity/specificity for torsion is approximately 93%/100% in a focused review, though the wider literature range runs roughly 69-91% sensitivity and 87-100% specificity depending on operator and equipment.^[2][3] A normal-flow or equivocal ultrasound does not fully exclude torsion in a patient with a high clinical suspicion — treat the clinical picture as primary and involve urology directly in that situation rather than trusting a reassuring scan alone.^[3]

• Actively exclude testicular torsion in every patient before treating for epididymitis — this is the first and most important goal of every encounter for acute scrotal pain.
• Match empiric antibiotic therapy to the actual likely etiology based on age and sexual history, rather than defaulting to one regimen for every patient.
• Relieve pain and inflammation while the antibiotic course takes effect.
• Prevent progression to abscess, orchitis, infertility, and chronic scrotal pain.
• Identify, notify, test, and empirically treat sexual partners when an STI is the cause.
• Avoid unnecessary broad-spectrum antibiotic use, and specifically avoid ciprofloxacin given current gonococcal resistance patterns.
• Confirm clinical improvement within the expected timeframe, and re-evaluate promptly — including for a missed torsion or an evolving abscess — when it does not occur.

Why ciprofloxacin is no longer used

Due to the rapid rise of quinolone-resistant N. gonorrhoeae, ciprofloxacin is no longer recommended for suspected or confirmed gonococcal epididymitis in Canada unless local resistance is documented to be under 5% — a threshold rarely met in practice today. It has been formally removed from PHAC's treatment table.^[1]

The evolving ceftriaxone dose

PHAC's still-current 2014 statement specifies ceftriaxone 250 mg IM as a single dose. The CDC's more recently updated (2021) guidance uses a higher 500 mg IM single dose (1 g if the patient weighs 150 kg or more), reflecting the same underlying concern about rising gonococcal antimicrobial resistance that led PHAC to remove ciprofloxacin — follow local/current public health guidance and antibiogram data where the two diverge.^[1][5]

Special situations

Cephalosporin contraindication with suspected/confirmed gonococcal epididymitis consult an experienced colleague (infectious diseases or an allergist) before substituting another agent — this is not a routine substitution decision.^[1]

• Scrotal support and elevation — a well-fitting athletic supporter or snug underwear — reduces traction pain and swelling and should be recommended from the first visit.
• Ice applied intermittently over the first 24-48 hours helps limit swelling and pain.
• Bed rest with scrotal elevation for more severe presentations in the first day or two, with a gradual return to normal activity as pain and swelling resolve; avoid heavy lifting or strenuous activity until acute inflammation has settled.
• Abstain from sexual activity until the patient's own treatment is complete (7 days after a single-dose regimen, or through completion of a multi-dose course) and symptoms have resolved, and until all current partners have also completed treatment — this mirrors standard STI-management counselling and prevents immediate reinfection.^[6]
• Partner notification and empiric treatment: for confirmed or suspected gonococcal or chlamydial epididymitis, notify, clinically assess, test, and provide empiric treatment to all sexual partners within the 60 days preceding symptom onset (or the date of specimen collection, if the patient was asymptomatic) — treat partners regardless of their own clinical findings and without waiting for their test results.^[6] Confirmed gonococcal epididymitis is nationally notifiable; report to local public health.^[1][6]
• Patient education on why torsion was ruled out, not just assumed: explain in plain language what specifically pointed away from torsion (gradual onset, preserved reflex, normal position) so the patient understands why they are going home with antibiotics rather than to the operating room — and knows exactly what change in symptoms (sudden worsening, a new or different quality of pain) should prompt an immediate return.
• Counsel on completing the full antibiotic course even as pain improves, and on realistic expectations: clinical improvement is expected within 2-3 days, but some residual tenderness can persist for weeks.^[2]

Children and prepubertal boys

PHAC's core recommendations in this chapter apply specifically to men presenting with symptoms of epididymitis and explicitly do not apply to prepubertal children, who need referral for special consideration, management, and treatment.^[1] Etiology in this group is frequently unclear and may relate to urine reflux or a post-infectious process rather than a typical bacterial ascending infection (see Recognize the Condition); a child under about 14 with epididymitis warrants urology referral to evaluate for an underlying anatomic abnormality.^[2] Torsion is also common in this age group (including neonatal torsion), which only raises the stakes of getting the differential right rather than lowering them.

Adolescents and young men

This is the age band where the epididymitis-versus-torsion diagnostic overlap is most consequential, and where a documented, real-world access problem exists: a survey of Canadian urologists found that ultrasound accessibility is inconsistent across the country, and that patients in rural locations or at centres with limited ultrasound access face a genuine, elevated risk of delayed torsion diagnosis and treatment.^[4] In this setting, an emergent urology consultation or transfer should be driven by clinical suspicion, not held up waiting for imaging that may not be readily available.^[4][3]

Men over about 50

Epididymitis in this age group is frequently the first clinical sign of previously undiagnosed bladder outlet obstruction from prostatic enlargement — arrange follow-up specifically to evaluate for this underlying obstruction once the acute infection has resolved, rather than treating the episode as an isolated event.^[2]

HIV-infected and other immunocompromised men

Consider a broader organism list — cytomegalovirus, Salmonella, Ureaplasma urealyticum, and mycobacteria (including from intravesical BCG) — when the typical empiric regimens do not produce the expected response.^[2]

Men on amiodarone

Amiodarone can cause a sterile, dose-related epididymitis that will not respond to antibiotics and instead requires dose reduction or discontinuation in consultation with the prescriber — worth specifically considering when the clinical picture and risk-factor history otherwise do not fit an infectious cause.^[2]

Recurrent or chronic epididymitis

Recurrent episodes, particularly in an older patient, warrant urology referral for structural evaluation. Chronic idiopathic epididymitis (persistent orchialgia without an identified infectious cause) is managed differently — an initial trial of NSAIDs with scrotal icing and elevation, with gabapentin or a tricyclic antidepressant considered for refractory cases under specialist direction — rather than repeated antibiotic courses.^[2]

All patients treated for epididymitis should show improvement within 48 hours of starting treatment; those who do not should be reassessed to re-evaluate the initial diagnosis (including for a missed torsion or an evolving abscess) and the antibiotic choice, rather than simply extending the same course.^[1] A specific follow-up visit within about a week is a reasonable default to confirm resolution — clinical improvement is generally expected within 2-3 days, though some residual tenderness can persist for weeks even after successful treatment.^[2]

• Confirmed gonococcal epididymitis: report to local public health, complete partner notification and empiric partner treatment for the preceding 60 days, and counsel abstinence until treatment is complete (7 days after a single-dose regimen, or through completion of a multi-dose course) and symptoms have resolved.^[1][6]
• Screen for reinfection at 6 months post-treatment — this generalizes PHAC's gonorrhea-specific reinfection-screening interval to any patient treated for STI-related epididymitis, given the shared sexual-network risk.^[6]
• Persistent induration, a new or enlarging mass, or fluctuance after an apparently adequate course: obtain scrotal ultrasound to exclude abscess or, less commonly, an underlying testicular tumour, rather than assuming the antibiotic course simply needs more time.
• Men over about 50: schedule specific follow-up to evaluate for underlying bladder outlet obstruction once the acute episode resolves.^[2]
• Children under about 14: confirm the urology referral for anatomic evaluation is actually completed, not just recommended at discharge.^[2]

1. Any new or persisting suspicion of testicular torsion at any point in the evaluation or treatment course — including after antibiotics have already been started: stop, and obtain emergent urology consultation immediately; do not wait for a scheduled follow-up or for imaging alone to resolve the question.^[1][3]
2. No improvement by 48 hours: reassess the initial diagnosis and treatment — reconsider torsion, obtain scrotal ultrasound to look for an abscess, and re-examine whether the empiric antibiotic actually matches the patient's real risk profile (age, sexual history, insertive anal intercourse).^[1]
3. Fluctuance, a rapidly enlarging or poorly defined scrotal mass, or any sign of Fournier's gangrene (rapidly spreading erythema, crepitus, disproportionate pain, systemic toxicity): emergent surgical/urologic referral — this is not managed with oral antibiotic escalation alone.
4. Persistent induration or a mass after an apparently complete and adequate course: scrotal ultrasound to exclude a retained abscess or an underlying testicular tumour before assuming simple slow resolution.
5. Recurrent epididymitis, particularly in an older patient: refer to urology for structural/obstructive workup rather than repeating empiric antibiotics indefinitely.

• Treating a gradual onset, or a positive Prehn's sign, as sufficient on its own to exclude testicular torsion — both are unreliable, and torsion still needs to be actively considered and, where equivocal, urgently evaluated.^[3][2]
• Waiting for Doppler ultrasound to be arranged and read before involving urology when clinical suspicion for torsion is genuinely high — every hour of delay measurably reduces the chance of testicular salvage.^[3]
• Defaulting to the same antibiotic regimen for every patient rather than stratifying by age and sexual history — particularly missing the enteric-organism risk in a man of any age who practices insertive anal intercourse.^[1][2]
• Continuing to use ciprofloxacin for suspected or confirmed gonococcal epididymitis given current resistance patterns.^[1]
• Forgetting partner notification, empiric partner treatment, and public health reporting for STI-related epididymitis.^[6]
• Assuming every case is infectious — missing amiodarone as a cause in a patient taking it, or a genuine anatomic abnormality in a prepubertal boy.^[2]
• Not arranging follow-up to confirm resolution, and not evaluating an older man for the underlying bladder outlet obstruction that a first episode of epididymitis often reveals.^[2]
• Treating a stable, low-access rural setting for imaging as a reason to defer urology involvement rather than a reason to escalate on clinical grounds alone.^[4]

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

STI-Likely Epididymitis (Sexually Active, Especially Under ~35)

Torsion must be excluded first (see Choose Initial Treatment and the Clinical Decision Algorithm). Combination therapy covers both gonorrhea and chlamydia.

Insertive Anal Intercourse, Any Age

Coliform organisms are a frequent cause in this group regardless of age or otherwise low enteric risk — this history detail changes therapy on its own.

Enteric-Organism-Likely Epididymitis (Age Over ~35, No STI Risk Factors, or Bladder-Outlet-Obstruction/Instrumentation History)

Monotherapy — no cephalosporin needed once genuine STI risk has been excluded by history.

Analgesia and Non-Pharmacologic Adjunct Support

Scrotal support/elevation and ice are first-line alongside scheduled analgesia — see Non-Pharmacologic Treatment.