Epididymo-orchitis is an infection and inflammation of the epididymis and testis and is one of the most common causes of acute scrotal pain in the adult male and one of the most important to diagnose and treat properly. Although it is not the life-threatening emergency that testicular torsion represents, inadequate management does have real and lasting consequences: chronic scrotal pain, testicular atrophy from chronic inflammation, formation of an abscess requiring surgical drainage, and, particularly relevant for young men, impaired fertility from damage to the sperm-producing and sperm-transporting structures.
The most important clinical problem in epididymo-orchitis is to differentiate it from testicular torsion in any man presenting with acute scrotal pain. Both conditions cause pain, swelling and tenderness of the scrotum. Mistaking torsion for epididymo-orchitis and giving antibiotics is a mistake in one direction that can lead to permanent loss of the testicle in a matter of hours. If you make the other mistake and operate for epididymo-orchitis you will be performing an unnecessary but harmless operation. If you are unsure, explore. Any clinician faced with acute scrotal pain should be guided by the surgical adage that a negative scrotal exploration is an acceptable outcome, but a missed torsion is not.
The epididymis is a long, coiled tube that rests on the back of each testis. It is through this tube that sperm pass and where they mature, after being produced by the testis. The sperm-producing and testosterone-producing organ itself is the testis. Epididymo-orchitis is inflammation, usually due to bacterial infection, of the epididymis (epididymitis) and, if the infection spreads to the adjacent testis, of the testicular tissue itself (orchitis). The two structures are anatomically contiguous and, thus, infection in the epididymis often spreads to involve the testis; this is the reason the combined term epididymo-orchitis is used more often than either term alone.
The infection usually reaches the epididymis by ascending spread from the urethra or bladder as bacteria travel upward along the vas deferens from a urethral or bladder infection to reach the epididymis. In sexually active young males, the main pathogens are sexually transmitted organisms, especially Chlamydia trachomatis and Neisseria gonorrhoeae. In older men and boys the most common route is from a urinary tract infection with enteric bacteria. At times, spread from a distant site of infection, particularly Mycobacterium tuberculosis , may cause epididymo-orchitis due to haematogenous seeding rather than by ascending spread.
Acute epididymo-orchitis is the most common clinical presentation with a short history of progressive scrotal pain, swelling and tenderness usually over days rather than hours. Depending upon the causative organism, fever, urinary symptoms and urethral discharge may be seen along with the scrotal findings. The most common form of epididymo-orchitis seen in clinical practice is acute bacterial epididymo-orchitis which requires early antibiotic therapy to avoid complications.
Chronic epididymo-orchitis means pain, swelling or tenderness of the epididymis and testis that has lasted for more than six weeks. This may be due to undertreated or inadequately treated acute epididymo-orchitis, low-grade infection, or post-infective inflammation that has not completely subsided despite appropriate antibiotic treatment. The chronic form of epididymo-orchitis is harder to treat than the acute form and may require long courses of antibiotics or in some cases surgery. Before attributing prolonged symptoms to ongoing epididymo-orchitis, other causes of chronic scrotal pain such as varicocele, hydrocele and scrotal neuralgia should also be excluded.
Of particular note is tuberculous epididymo-orchitis as a specific and important form. Genitourinary tuberculosis is not uncommon in India, epididymis being one of the common sites of extra-pulmonary TB in male genital tract. TB epididymo-orchitis tends to present in a more insidious manner than bacterial epididymo-orchitis with a more gradual, often painless or minimally painful scrotal swelling, sometimes with a sinus through the scrotal skin, the classic beaded epididymis on palpation and induration or sinus formation of the scrotal skin should always raise suspicion of TB. Specific microbiological and histopathological testing is needed to diagnose. Treatment is anti TB chemotherapy as per standard RNTCP guidelines and not standard urological antibiotics.
It is important to recognise viral orchitis from mumps as the most common cause of orchitis in post-pubertal males who are not vaccinated against MMR. Mumps orchitis typically develops two to eight days after the onset of parotid swelling, and is characterised by unilateral or bilateral testicular swelling and pain. It is not treated with antibiotics but with supportive care including scrotal support, analgesia and bed rest. Bilateral mumps orchitis can cause testicular atrophy and infertility. This is one of the important reasons to recommend the MMR vaccine in childhood.
The symptoms of epididymo-orchitis are usually slower to develop than the sudden catastrophic pain of torsion, but the distinction is not absolute and acute clinical assessment is always needed to exclude torsion before treating for infection.
Gradual Onset Scrotal Pain & Swelling
The causative organism and appropriate treatment vary widely with age, and age-guided empirical antibiotic selection is an important principle when culture results are pending. Below is a summary of the most common causes by age:
| Age Group | Most Likely Cause | Investigation Priority | Treatment Approach |
|---|---|---|---|
| Boys under 14 | Enteric organisms (E. coli, Haemophilus) | Urine culture; renal tract ultrasound | Broad-spectrum antibiotics; investigate for urinary anomaly |
| Men 14–35 | STI: Chlamydia trachomatis / N. gonorrhoeae | Urethral swab / NAAT; partner notification | Ceftriaxone + doxycycline; partner treatment |
| Men 35–65 | Enteric organisms (E. coli) from UTI / BPH | Urine culture; MSU; PSA; renal/bladder USS | Quinolone or cephalosporin; treat BPH if present |
| Men over 65 | Enteric organisms; chronic urinary stasis | Urine culture; prostate/bladder assessment | Antibiotics; treat bladder outlet obstruction if present |
| Immunocompromised / TB risk | Mycobacterium tuberculosis | Urine AFB; FNAC if needed; CXR | Anti-TB therapy (RNTCP regimen); specialist management |
Chlamydia trachomatis is the most common infecting organism in young sexually active men aged 14 to 35 years, and Neisseria gonorrhoeae is also important, particularly in those with urethral discharge. Both are STIs spread through unprotected sexual intercourse. The infection then travels from the urethra up the vas deferens to the epididymis. Treatment is a two-antibiotic regimen to cover both organisms: intramuscular ceftriaxone for gonorrhoea and oral doxycycline for two to four weeks for chlamydia. Partner notification and treatment simultaneously are critical.
Enteric gram-negative organisms, particularly Escherichia coli, are most common in older men and boys, usually ascending from a urinary tract infection associated with bladder outlet obstruction from BPH, urethral stricture, or other causes of incomplete bladder emptying. Investigation for an underlying urinary tract anomaly is indicated after a first episode of bacterial epididymo-orchitis in boys, as an anatomical predisposing cause is more likely in the paediatric group than in adults. In view of the endemic burden of TB, genitourinary tuberculosis is an important cause in India, though its presentation is less obvious. It should be kept in mind in any atypical presentation, especially with a beaded epididymis, scrotal sinus, or failure to respond to standard antibiotics.
Epididymo-orchitis can be recurrent and for some men this is a recurring problem, not a single episode. The risk and cause of recurrence depend on whether the underlying predisposing factor is identified and treated. The most common reason for recurrence in young men with STI-related epididymo-orchitis is reinfection from an untreated or newly acquired STI, and thus consistent safe sex practices and treatment of partners are important. In older men with BPH or other bladder outlet obstruction, incomplete emptying creates a persistent reservoir for bacterial ascent, and recurrent epididymo-orchitis will continue until the underlying obstruction is adequately treated. Urethral stricture resulting in incomplete bladder emptying likewise leads to recurrent ascending infection and definitive stricture treatment is required to break the cycle of recurrence.
The most common cause of apparent recurrence that is actually persistent or relapsing infection from the original episode is inadequately treated acute epididymo-orchitis with too short an antibiotic course, the wrong antibiotic for the causative organism or poor compliance with the prescribed course. Bacterial epididymo-orchitis requires a minimum of 2-4 weeks of antibiotics to fully treat the infection in the relatively avascular and poorly penetrated epididymal tissue, and shorter courses often result in incomplete treatment. A recurrent or persistent presentation of symptoms despite antibiotic therapy may be due to a recognised complication of inadequately treated epididymo-orchitis , the epididymal abscess . Not further antibiotics but surgical drainage is required.
Men who experience two or more episodes of epididymo-orchitis should be fully evaluated for an underlying cause, including urine culture, STI testing, uroflowmetry and post-void residual, prostate evaluation in older men, and scrotal Doppler, rather than treating each episode in isolation without understanding why the infection recurs. The only thing we can do to prevent further attacks is to remove the predisposing cause.
The most important clinical decision in the management of acute scrotal pain is to distinguish epididymo-orchitis from testicular torsion, because the treatment of torsion as epididymo-orchitis with antibiotics may cost the testis to ischaemia when the correct diagnosis is missed. The key differences are: Torsion usually presents suddenly and catastrophically, whereas epididymo-orchitis evolves over hours to days; The cremasteric reflex is absent in torsion, but usually present in epididymo-orchitis; Systemic features such as urethral discharge, urinary symptoms and early fever are more in keeping with epididymo-orchitis; Elevation of the scrotum relieves the pain of epididymo-orchitis (Prehn’s positive) but not torsion. Colour Doppler ultrasound showing preserved or increased blood flow to the testis suggests epididymo-orchitis, and absent or reduced blood flow suggests torsion. However, diagnostic uncertainty mandates emergency scrotal exploration as the proper management, a negative exploration is safe and a missed torsion is not.
Most men with acute epididymo-orchitis have significant improvement in pain and systemic symptoms within 3 to 5 days of initiating appropriate antibiotics. However, the scrotal swelling and epididymal tenderness observed on examination may take significantly longer to resolve fully, usually four to six weeks, and sometimes longer in more severe episodes. This is important in patient counselling. Persistent scrotal swelling for several weeks despite improving pain and systemic symptoms does not necessarily indicate treatment failure, as the resolution of the inflammatory mass proceeds more slowly than clinical improvement. If there is no improvement after 48 to 72 hours on appropriate antibiotics or if there is any clinical deterioration, repeat ultrasound should be performed to exclude abscess formation.
Most men with epididymo-orchitis can be treated as outpatients with oral antibiotics if they are systemically well, the infection is not severe and they are reliable with taking medication. Hospital admission is indicated in the presence of severe infection with high fever, rigours or signs of sepsis; inability to tolerate oral antibiotics (e.g. vomiting); suspected abscess requiring surgical drainage; immunocompromised patients; young children; or if clinical uncertainty exists regarding torsion necessitating surgical exploration. In men treated as outpatients, a clear review plan at 48 to 72 hours should confirm improvement, with a low threshold for admission if not improving as expected.
Yes, epididymo-orchitis can affect male fertility in a number of ways but the risk is linked to the severity of the infection and whether both testes are involved. The epididymis is an important part of sperm maturation and transport. Epididymal inflammation can cause damage to the epithelial cells lining the epididymal tubule leading to post-infective epididymal scarring which can block the passage of sperm, which when bilateral, results in obstructive azoospermia . Orchitis can cause direct marked inflammation of the testis and impair spermatogenesis in the affected testis. The most well-documented fertility risk is bilateral mumps orchitis. In practice, major loss of fertility in men who are treated promptly and adequately for epididymo-orchitis is uncommon. However, in men planning conception, or in those with severe or bilateral infection, a semen analysis six to twelve months after recovery is reasonable for those seeking objective reassurance.
Sexually transmitted infections , particularly Chlamydia trachomatis , and Neisseria gonorrhoeae in those with urethral discharge , are a common cause of epididymo-orchitis in men under the age of about 35 . It is essentially a STI complication in this age group and is sexually transmitted from an infected partner via unprotected sexual intercourse. The patient and recent sexual partners require testing and treatment. In older men, epididymo-orchitis is more often caused by enteric bacteria from a urinary tract infection related to bladder outlet obstruction or other urological cause and is not sexually transmitted. It is usually due to enteric bacteria in children and boys and is not sexually transmitted. So the answer depends on the patient’s age group: probably STI related in younger sexually active men, not STI related in older men and boys.
An epididymal or testicular abscess is a localised collection of pus which occurs as a complication of inadequately treated or very severe epididymo-orchitis, when the bacterial infection is not fully controlled by antibiotics and the body’s inflammatory response walls off the infection into a purulent collection within the epididymis or testicular tissue. Clinically, an abscess should be suspected if symptoms do not improve or worsen despite appropriate antibiotics. Persistent fever, progressive swelling and increasing pain after 48 to 72 hours of antibiotic treatment are warning signs. The typical loculated collection is filled with fluid and the diagnosis is usually confirmed by scrotal ultrasound. Antibiotics alone cannot penetrate and sterilise an established collection of abscess and therefore surgical drainage is required. In the setting of drainage, orchidectomy may be performed if the extent of involvement is such that the testis itself is non-viable, but testicular-sparing surgery is always preferred where possible.
Genitourinary tuberculosis is an important cause of epididymo-orchitis in India and should be specifically considered in cases with atypical clinical presentation. The classical presentation of TB epididymo-orchitis is an insidious onset, often with little pain despite marked swelling, a characteristically beaded or craggy epididymis on palpation and the history of known TB or relevant risk factors. In advanced cases the scrotal skin may be involved with formation of a sinus tract, a cold abscess discharging through the skin. Diagnosis includes urine AFB testing, early morning urine samples for TB culture and sometimes fine needle aspiration cytology (FNAC) or biopsy of epididymal mass for histopathological confirmation. The management includes standard anti-TB chemotherapy as per RNTCP guidelines and not urological antibiotics. Many men with TB epididymo-orchitis are treated with ineffective standard antibiotics for months before the correct diagnosis is made.
Yes, it is strongly recommended to avoid sexual intercourse during the acute treatment phase, for various reasons. If it is a STI, continuing to have sex risks transmitting the infection to partners and being reinfected by an untreated partner. Sexual activity during the acute phase of epididymo-orchitis of any aetiology causes discomfort and exacerbates swelling of the scrotum by increasing blood flow to the genitalia. Complete abstinence from sexual activity, including unprotected sex, is advised until antibiotics treatment is completed, STI testing is negative, and all sexual partners have been adequately tested and treated. If you have sex again before meeting these conditions, you risk recurrence, reinfection and onwards STI transmission.
Epididymitis is inflammation, usually localised to the epididymis, the coiled tube at the back of the testis where sperm mature and travel. Orchitis means inflammation involving the testis proper. In clinical practice, infection typically begins in the epididymis by ascending spread from the urethra; if not appropriately treated, it spreads into the adjacent testicular tissue, resulting in combined epididymo-orchitis. Pure orchitis without epididymal involvement is rarer and is more often associated with viral aetiology, especially mumps. Isolated epididymitis without testicular involvement is seen early in the course of infection or in milder cases. The clinical distinction is of some importance, as isolated orchitis responds to different management (supportive rather than antibiotic in viral cases), whereas ascending bacterial infection affecting the epididymis requires antibiotic treatment regardless of testicular involvement.
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