Epididymo-orchitis

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Epididymo-orchitis is inflammation of the epididymis with or without testicular involvement. Chlamydia and gonorrhoea are important after sexual exposure; enteric infection is associated with urinary pathology, instrumentation or insertive anal sex.

Testicular torsion is the critical boundary and can occur at any age. Neither urinary abnormalities nor ultrasound should delay emergency exploration when history and examination are strongly suspicious.

Management combines empirical cause-directed therapy after sampling, analgesia and scrotal support with partner notification and test-of-cure arrangements when a sexually transmitted organism is identified.

Clinical improvement begins with reduced pain and fever, while swelling may take weeks to settle. A persistent discrete intratesticular abnormality, however, is not explained by slow recovery and requires ultrasound and specialist review.

Admission is appropriate for sepsis, intolerable pain, vomiting, immune compromise, suspected abscess or inability to adhere to oral care. Fournier gangrene requires immediate resuscitation, broad intravenous therapy and surgical debridement.

Key points

Epididymo-orchitis usually causes unilateral epididymal pain and swelling developing over hours to days; torsion is the time-critical mimic.
Age alone does not determine cause: use sexual history, urethral symptoms, urinary pathology, anal exposure, instrumentation and culture.
Send first-catch urine NAAT for gonorrhoea and chlamydia and midstream urine culture when enteric infection is possible.
Do not allow Doppler ultrasound to delay emergency exploration when clinical suspicion of torsion is high.
For likely gonorrhoea or chlamydia, give ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg twice daily for 10 to 14 days.
For likely mixed sexual and enteric exposure, ceftriaxone 1 g once plus levofloxacin 500 mg once daily for 10 days is an option.
When gonorrhoea is excluded and enteric organisms are likely, ofloxacin 200 mg twice daily for 14 days or levofloxacin 500 mg daily for 10 days may be used under current restrictions.
Advise rest, scrotal support, analgesia and abstinence until treatment and partner management are complete; review if not improving within three days.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Sexually transmitted pathogens

Chlamydia trachomatis and Neisseria gonorrhoeae ascend from the urethra and are important causes after sexual exposure.

Enteric urinary organisms

Escherichia coli and related Gram-negative organisms spread with urinary obstruction, instrumentation, bacteriuria or insertive anal intercourse.

Viral and unusual causes

Mumps, tuberculosis, brucellosis and opportunistic infection are uncommon but relevant with bilateral disease, epidemiological exposure or immune compromise.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Ascending ductal spread
Organisms move from urethra through ejaculatory and vasal pathways into the epididymis, where dependent anatomy often makes the tail inflamed first.
2
Inflammatory oedema
Neutrophil recruitment and vascular leak enlarge the epididymis and surrounding tissues, producing pain, hydrocele and reactive testicular involvement.
3
Pressure-related injury
Severe oedema and inflammation can impair local blood flow, causing infarction or abscess despite antimicrobial treatment.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Gradual unilateral inflammation

Pain and swelling commonly begin in the epididymal tail and progress over hours or days, with tenderness, erythema and sometimes hydrocele.

Torsion patternRed flag

Abrupt severe pain, nausea, high-riding or horizontal testis and absent cremasteric reflex increases torsion probability and requires emergency urology.

Sexually transmitted context

Urethral discharge, dysuria, new partner, condomless sex or known contact increases gonorrhoea and chlamydia probability.

Enteric urinary context

Recent instrumentation, obstruction, bacteriuria, prostate disease or insertive anal sex increases enteric Gram-negative infection probability.

Severe soft-tissue infectionRed flag

Perineal necrosis, bullae, crepitus, rapidly spreading erythema or disproportionate pain suggests Fournier gangrene rather than uncomplicated disease.

Red flags requiring action

Sudden severe pain or a high-riding testis requires immediate torsion assessment.
Sepsis, rapidly spreading erythema, crepitus or disproportionate pain suggests Fournier gangrene.
A fluctuant mass, persistent fever or worsening swelling suggests abscess or infarction requiring urology.
Bilateral symptoms, mumps features or immune compromise widens the infectious differential.
A persistent testicular mass after treatment requires urgent assessment for malignancy.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Focused genital and abdominal examinationFirst step
Why
Localise epididymal tenderness and assess torsion, hernia, abscess and perineal necrosis.
Interpretation and limitations
Examine both testes, lie and cremasteric reflex, inguinal regions, abdomen and perineum. A preserved reflex does not completely exclude torsion.
02
First-catch urine NAAT
Why
Detect Chlamydia trachomatis and Neisseria gonorrhoeae before therapy.
Interpretation and limitations
Use first-catch rather than midstream technique and obtain throat or rectal samples according to exposure.
03
Gonococcal culture
Why
Obtain susceptibility information when gonorrhoea is suspected or NAAT is positive.
Interpretation and limitations
Collect urethral and relevant exposed-site culture before ceftriaxone when feasible, but do not postpone necessary treatment.
04
Midstream urine culture
Why
Identify enteric urinary organisms and susceptibility where urinary pathology is plausible.
Interpretation and limitations
Interpret with urinary symptoms and instrumentation history; a negative culture does not exclude an STI-associated syndrome.
05
Scrotal Doppler ultrasound
Why
Evaluate uncertain diagnosis, abscess, tumour, infarction or another lesion.
Interpretation and limitations
Use when it changes management, but do not delay exploration for likely torsion; preserved flow can occasionally mislead.
06
HIV, syphilis and broader STI screen
Why
Detect concurrent sexually transmitted infections and complete sexual-health care.
Interpretation and limitations
Tailor tests to exposure window and vaccination status and repeat serology when an early test may precede detectability.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Testicular torsion

Spermatic-cord twisting causes abrupt ischaemic pain and requires immediate exploration because delay risks irreversible testicular loss.

Torsion of appendage

A twisted testicular appendage causes focal upper-pole tenderness and sometimes a blue-dot sign without the systemic infection pattern.

Incarcerated hernia

Painful irreducible inguinoscrotal swelling with vomiting or clinical bowel obstruction requires immediate emergency general surgical assessment.

Testicular tumour

A solid intratesticular mass may be painless or painful after haemorrhage and requires urgent ultrasound and urology referral.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01TORSIONProtect the ischaemic testisFirst stepOnset, testicular lie, nausea or examination creates meaningful suspicion of testicular torsion.

1Contact urology immediately, document onset, give analgesia, keep the patient fasted and prepare for emergency exploration.
2Do not wait for urine results, improvement after analgesia or routine outpatient ultrasound when suspicion is high.
3Manual detorsion may be attempted only by an experienced clinician when surgery is not delayed and does not replace exploration and fixation.
4Continue reassessing both testes and communicate any diagnostic uncertainty directly to the operating urologist.

02STI LIKELYTreat gonorrhoea and chlamydiaSexual exposure, urethritis or absent urinary pathology makes a sexually transmitted cause likely.

1Collect first-catch NAAT and gonococcal cultures from relevant sites before treatment when this creates no delay.
2Give ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg orally twice daily for 10 to 14 days.
3Arrange full STI screening, partner notification and treatment, and advise abstinence until the required completion interval.
4Review at about three days if symptoms are not improving and arrange gonorrhoea test of cure according to guidance.

03ENTERIC LIKELYTreat urinary-source infectionGonorrhoea is excluded and instrumentation, urinary pathology or culture supports enteric organisms.

1Obtain urine culture, assess prostate and obstruction features and image when abscess or structural disease is suspected.
2Use ofloxacin 200 mg twice daily for 14 days or levofloxacin 500 mg daily for 10 days only when fluoroquinolone restrictions permit.
3Provide rest, scrotal support and analgesia while monitoring fever, swelling and urinary function.
4Refer to urology for recurrence, obstruction, abscess, persistent mass or failure to respond to active therapy.

04REVIEWCheck response and sequelaePain, swelling or fever persists three days after appropriate empirical treatment.

1AlternativeReassess for torsion, abscess, infarction, resistant organism and an alternative scrotal mass.
2Review NAAT, gonococcal and urine cultures and adjust treatment and partner plans promptly.
3Arrange ultrasound and urology assessment for persistent swelling, focal collection or testicular mass.
4Address adherence, abstinence, partner treatment and test-of-cure requirements before discharge from follow-up.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

BASHH regimen for epididymo-orchitis likely caused by gonorrhoea or chlamydia.

Ceftriaxone plus doxycycline

Give ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg orally twice daily for 10 to 14 days.

Check severe beta-lactam allergy, obtain gonococcal culture when feasible, avoid doxycycline in pregnancy and review photosensitivity, oesophagitis and interacting cations.

Covers gonorrhoea and enteric organisms when mixed sexual and enteric exposure is plausible.

Ceftriaxone plus levofloxacin

Give ceftriaxone 1 g intramuscularly once plus levofloxacin 500 mg orally once daily for 10 days.

Use levofloxacin only under MHRA restrictions; review renal, tendon, neurological, psychiatric, vascular, cardiac and glycaemic risk and interactions.

Provides genital-tissue activity against susceptible enteric organisms in selected epididymo-orchitis.

Ofloxacin

Give 200 mg orally twice daily for 14 days only when gonorrhoea is excluded and enteric organisms are likely.

Apply fluoroquinolone restrictions, adjust for renal impairment, review QT and serious persistent adverse-effect risk, and do not use while gonorrhoea remains possible.

Alternative once-daily enteric regimen with tissue penetration for selected adults.

Levofloxacin

Give 500 mg orally once daily for 10 days only when gonorrhoea is excluded and an enteric cause is likely.

Use only when recommended alternatives are inappropriate; assess renal function, interactions and tendon, neurological, psychiatric, vascular and glycaemic risk.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Abscess and infarction

Progressive suppuration or pressure-impaired blood flow causes focal collection, necrosis and possible need for drainage or orchidectomy.

Infertility

Bilateral inflammation or ductal scarring can impair sperm transport and testicular function, particularly after mumps orchitis.

Chronic scrotal pain

Inflammatory and neuropathic pain can persist after microbiological cure and requires reassessment rather than indefinite antibiotics.

Transmission and reinfection

Untreated partners can develop complications and reinfect the patient, making partner notification and abstinence advice essential.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Advise urgent reassessment for sudden worsening pain, high-riding testis, systemic deterioration or spreading perineal change.
Review within about three days if pain and swelling are not clearly improving.
Check NAAT, gonococcal culture and urine culture and tailor therapy and partner management promptly.
Arrange gonorrhoea test of cure and repeat STI testing according to organism, site, treatment and guidance.
Ensure persistent swelling or a testicular mass receives ultrasound and urology assessment.
Offer written sexual-health contact details so confidential partner notification and follow-up testing remain practically accessible locally.
Document symptom-onset time, torsion assessment, microbiological samples, exposure-based regimen choice and the exact partner-management plan.
If mumps is suspected, assess parotitis, vaccination and public-health implications and avoid substituting antibacterial escalation for a viral diagnosis.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Age is not an organism test

Sexual practice, urethritis, urinary pathology and instrumentation predict cause more reliably than an arbitrary age threshold.

Ultrasound cannot buy time

Imaging is valuable in uncertainty and complications but must not delay exploration when torsion is clinically likely.

Exposure directs sampling

Throat and rectal infection may coexist without symptoms, so sampling sites follow sexual exposure rather than genital symptoms alone.

Supportive care matters

Rest, scrotal elevation and analgesia reduce pain while antimicrobial treatment controls infection; swelling can resolve more slowly.

Persistent mass needs a new diagnosis

Residual enlargement may be inflammatory, but malignancy, infarction or abscess must be excluded rather than treated repeatedly.

Pain relief does not exclude torsion

Spontaneous or analgesic-associated improvement can occur after intermittent detorsion, so the original abrupt history and abnormal lie remain clinically important.

Partners may lack symptoms

Asymptomatic chlamydia or gonorrhoea in a partner still permits transmission and complications, making confidential notification and treatment central to preventing recurrence.

11Common pitfallsFrequent interpretation and management errors.

01
Do not exclude testicular torsion because dysuria, pyuria or gradual symptoms appear to support infection.
02
Do not wait for Doppler ultrasound when emergency urological exploration is clinically indicated.
03
Do not use ceftriaxone alone when chlamydial infection has not been excluded.
04
Do not give an enteric-only fluoroquinolone regimen while gonorrhoea remains possible.
05
Do not omit partner notification, abstinence advice and full STI screening after presumed sexually transmitted disease.
06
Do not interpret a slowly resolving diffuse swelling as treatment failure without first checking pain, fever, cultures and whether a persistent focal mass is present.