Epididymitis · What Is It, Symptoms, Causes, Diagnosis, Treatment, and More

Epididymitis refers to inflammation of the epididymis, which is a coiled tube in the back of the testicle that transports and stores sperm. It carries sperm from the testes to the vas deferens, and from there to the ejaculatory ducts.  

For a sudden onset of inflammation that lasts less than 6 weeks, epididymitis is considered acute. Chronic epididymitis, on the other hand, lasts more than 6 weeks. Individuals of any age can be affected, but the majority of cases occur in adults between 20 and 59 years old. 

The most common cause of epididymitis is a bacterial infection. Most often, the infection begins in the urethra, bladder, or prostate, and can reach the epididymis through retrograde spread. Other, less frequent, spreading routes include the bloodstream or the lymphatic system. 

In children, the infectious pathogen is typically Escherichia coli (E. coli), a species of opportunistic bacteria which normally colonizes the intestines, but can also cause urinary tract infections.  

For adults under 35 years of age, the most common causes include paramyxoviruses like the mumps virus and sexually transmitted infections (STIs) like gonorrhea and chlamydia, caused by the bacteria Neisseria gonorrhoeae and Chlamydia trachomatis, respectively. For this reason, sexually active adults, especially those practicing anal intercourse, are at an increased risk for epididymitis. Individuals with obstructions or congenital abnormalities of the urinary tract are also at increased risk. Other non-infectious causes of epididymitis include trauma, vasculitis (i.e., inflammation of blood vessels), medications (e.g., amiodarone), and autoimmune diseases. Finally, a portion of cases are idiopathic, meaning there is no known cause.  

In adults over 35 years old, the most common causes of epididymitis include E. coli and Pseudomonas aeruginosa, as well as genitourinary tuberculosis.  

Epididymitis’ symptoms can appear suddenly or gradually, and include redness, swelling, and pain in the scrotum that can radiate to the lower abdomen. Some cases of epididymitis occur concomitantly with inflammation of the testicles; this is referred to as epididymo-orchitis.  

If epididymitis is a result of a sexually transmitted infection (STI), it can be preceded by genital skin lesions and/or urethral discharge. Other lower urinary tract symptoms can also occur, such as difficult or painful urination (i.e., dysuria), as well as changes to urinary frequency and urgency. Additionally, individuals with severe systemic infections may experience nausea, fever, and chills.  

Differential diagnoses involve considering various possible conditions that could be causing symptoms and then ruling out each one through use of history, clinical evaluation, diagnostic tests, and critical thinking. This process helps to narrow down the list of potential diagnoses to determine the most likely cause of the symptoms. 

Differential diagnoses can be broken down into four categories: most likely, less likely, least likely, and can’t miss. Most likely diagnoses are conditions most probable based on symptoms and clinical presentation. Less likely diagnoses are not as probable but should still be considered. On the other hand, least likely diagnoses can be considered if other, more probably conditions are excluded. Finally, can’t miss diagnoses are less common but critical to promptly identify and treat as they can lead to severe consequences.  

Differential diagnoses for epididymitis include:  

Most likely: 

- STI: These infections can directly cause epididymitis by spreading to the epididymis. 

- UTI: UTIs can spread from the urinary tract to the epididymis. 

- Epididymo-orchitis: Inflammation extending from the epididymis to the testis. This condition is closely related to epididymitis as it involves the same anatomical structures.  

Less likely:  

- Reactive hydrocele: Fluid accumulation around the testicle due to inflammation. While it can occur secondary to epididymitis, it’s not a direct cause. 

- Spermatocele: A benign cyst in the epididymis. It can be mistaken for epididymitis but doesn’t cause inflammation.  

- Varicocele: Enlarged veins within the scrotum.  

Least likely:  

- Scrotal hernia: Protrusion of abdominal contents into the scrotum. This condition is unrelated to the epididymis but can cause scrotal swelling. 

- Idiopathic scrotal edema: Swelling of the scrotum without a clear cause.  

- Henoch-Schönlein purpura: A vasculitis that can cause scrotal pain and swelling.  

Can’t miss:  

- Testicular torsion: A surgical emergency where the spermatic cord twists, cutting off blood supply to the testicle. It presents with acute scrotal pain and swelling, similar to epididymitis, but requires immediate intervention. 

- Fournier’s gangrene: A life-threatening necrotizing fasciitis of the genital area. It can present with severe pain and swelling. 

- Testicular tumor: Malignant growths in the testicle. It can present with a painless mass or swelling in the scrotum. 

Diagnosis of acute or chronic epididymitis beings with a history and physical examination. Helpful physical examination signs include the cremasteric reflex which can be normal or positive with epididymitis (i.e., when upper thigh touched, ipsilateral testicle elevates), as well as Prehn sign which is also typically positive (i.e., pain relief with scrotal elevation). Additional evaluations that aid in diagnosis involve STI screenings, urine and blood tests, and ultrasound imaging.  

An important differential diagnosis is testicular torsion, a surgical emergency that occurs when a testicle twists cutting off its blood supply. These two conditions differ among affected age groups; pain and swelling location; testicular position; systemic and associated symptoms; cremasteric reflex, which is absent with testicular torsion; and Prehn sign, which is negative in testicular torsion.  

In uncertain cases, surgery may be performed to further explore the area and rule out testicular torsion.  

Pain and discomfort associated with epididymitis are managed by rest, elevation of the scrotum, cold packs, and non-steroidal anti-inflammatory drugs (NSAIDs). Additionally, infectious cases of epididymitis can be treated with antibiotics. The type and duration of antibiotic treatment depends on the individual’s age, sexual activity, signs and symptoms, and medical history. Commonly prescribed antibiotics, which can be used alone or in combination, typically include quinolones, doxycycline, and ceftriaxone. If epididymitis is caused by a sexually transmitted infection, the clinician may recommend that the individual’s sexual partner also undergo antibiotic treatment.  

On the other hand, non-infectious cases of epididymitis need treatment for their underlying cause, such as the withdrawal of any causative medication. 

Though most individuals can be treated from home, hospitalization may be considered for severe cases, systemic infections, or individuals with comorbid conditions such as diabetes or immunosuppression. Surgery is typically not recommended, due to its high failure rate and potential risk of infertility.