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Orchitis is swelling (inflammation) of one or both of the testicles.

Epididymo-orchitis; Testis infection

Orchitis may be caused by an infection from many different types of bacteria and viruses. It is usually a result of epididymitis, inflammation of the tube that connects the vas deferens and the testicle.

The most common virus that causes orchitis is mumps. It most often occurs in boys after puberty, and is rare before the age of 10. Orchitis usually develops 4 - 6 days after the mumps. Some boys who get orchitis caused by mumps will have shrinking of the testicles (testicular atrophy).

Orchitis can develop in men with the rare disease brucellosis.

Orchitis may also occur along with infections of the prostate or epididymis. It may be caused by sexually transmitted diseases (STD) such as gonorrhea or chlamydia. The rate of sexually transmitted orchitis or epididymitis is higher in men ages 19 - 35.

Risk factors for orchitis not due to an STD include:

• Being older than age 45
• Long-term use of a Foley catheter
• Not being vaccinated against the mumps
• Problems of the urinary tract that occurred at birth (congenital)
• Regular urinary tract infections
• Surgery of the urinary tract (genitourinary surgery)

Risk factors for sexually-transmitted orchitis include:

• High-risk sexual behaviors
• Multiple sexual partners
• Personal history of gonorrhea or other STD
• Sexual partner with a diagnosed STD

• Blood in the semen
• Discharge from penis
• Fever
• Groin pain
• Pain with intercourse or ejaculation
• Pain with urination (dysuria)
• Scrotal swelling
• Tender, swollen groin area on affected side
• Tender, swollen, heavy feeling in the testicle
• Testicle pain that is made worse by a bowel movement or straining

A physical examination may show:

• Enlarged or tender prostate gland
• Tender and enlarged lymph nodes in the groin (inguinal) area on the affected side
• Tender and enlarged testicle on the affected side

Tests may include:

• Complete blood count (CBC)
• Testicular ultrasound
• Tests to screen for chlamydia and gonorrhea (urethral smear)
• Urinalysis
• Urine culture (clean catch) -- may need several samples, including initial stream, mid-stream, and after prostate massage

Getting the right diagnosis and treatment for orchitis caused by bacteria can usually preserve the normal testicle function.

Mumps orchitis cannot be treated and the outcome can vary. Men who have had mumps orchitis have become sterile.

Orchitis may cause infertility and shrinking (atrophy) of one or both testicles.

Other potential complications include:

• Chronic epididymitis
• Fistula on the skin of the scrotum (cutaneous scrotal fistula)
• Scrotal abscess
• Death of testicle tissue (testicular infarction)

Acute pain in the scrotum or testicles can be a surgical emergency. If you have sudden pain in the scrotum or testicles, get immediate medical attention.

Call the local emergency number (such as 911) or go to the nearest emergency room if you experience sudden pain in the testicle.

Getting vaccinated against mumps will prevent mumps-associated orchitis. Safer sex behaviors, such as having only one partner at a time (monogamy) and condom use, will decrease the chance of developing orchitis as a result of a sexually transmitted disease.

Nickel JC. Inflammatory Conditions of the Male Genitourinary Tract: Prostatitis and Related Conditions, Orchitis, and Epididymitis. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 9.

Mason WH. Mumps. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 245.