Health A-Z

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What Is It?

Epididymitis is an inflammation of the epididymis. The epididymis is the coiled tube at the back of the testicle. In most cases, an infection causes this inflammation.

Orchitis is an infection of the testicle. It is much less common than epididymitis. Orchitis usually spreads to the testicle through the bloodstream. Viruses commonly cause the infection.

Epididymo-orchitis is an inflammation of both the epididymis and the testicle.

Infections that cause epididymitis usually are related to age, medical history and sexual activity.

Before puberty. Intestinal bacteria, such as E. coli, most often cause epididymitis. The bacteria travel from the bladder or some other site in the urinary tract.

In many cases, a birth-related abnormality affects the urinary tract's structure or function. These abnormalities increase the boy's risk of urinary tract infections (UTIs). The UTIs may eventually spread to the epididymis.

For example, a boy may be born with a structural abnormality of the tube that carries urine through the penis.

In sexually active men. The most common cause of epididymitis is a sexually transmitted disease (STD). The STD is usually chlamydia, gonorrhea or both.

The initial site of infection is the urethra. This is the tube-like passageway that carries urine and semen out of the penis. Eventually, bacteria spread backward through the reproductive tract to attack the epididymis.

This condition may appear several months after the sexual encounter that caused the STD. In some cases, the man first has symptoms of an infected urethra. In other cases, symptoms of epididymitis are the first and only signs of an STD.

Among men who have anal intercourse, epididymitis usually is caused by intestinal bacteria from the anus. These bacteria enter the urethra through the penis. They then travel backward through the reproductive tract.

In adults with a high-risk medical history. Some men have a history of UTIs or prostate infections. For them, epididymitis usually is caused by intestinal bacteria that have spread from the infected site.

After surgery, testing or catheterization. Epididymitis may develop after surgery or a diagnostic test that involves the bladder or urethra. Or it may occur after a catheter has been inserted to collect urine.

In these cases, the infection usually is caused by intestinal bacteria. These bacteria enter the urethra or bladder, either during the procedure or through the catheter.

Other forms (all age groups). Rarely, epididymitis can occur when a systemic (whole body) infection spreads through the bloodstream and moves to the epididymis.

A noninfectious form of this condition can develop in men who take amiodarone (Cordarone, Pacerone). This is a heart medication that seems to build up in the epididymis.

Some cases have been blamed on intense exercise, especially heavy lifting. The strain of heavy lifting may force urine from the bladder into the epididymis. There, it can cause a form of chemical irritation that triggers epididymitis.

Of unknown origin. Noninfectious epididymitis is fairly common. Its cause is not clear.

Many cases of this condition can be treated at home. But some are so severe that hospitalization is necessary.

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From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.

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