Prostatitis is inflammation of the prostate gland. The inflammation can be due to an infection as well as other various causes. Prostatitis accounts for nearly 2 million visits per year to outpatient urology practices in the United States.

The prostate gland is part of the male reproductive system, and it is a walnut-sized gland found in men that is located below the bladder and in front of the rectum. It surrounds the urethra, the tube through which urine and semen exit the body. Its main function is to produce seminal fluid in order to transport sperm through the urethra.

The NIH consensus definition and classification of prostatitis:

Acute bacterial prostatitis:
Caused by a bacterial infection and it typically starts suddenly and may include flu-like symptoms. It is the least common of the four types of prostatitis.
Chronic bacterial prostatitis:
Characterized by recurrent bacterial infections of the prostate gland. Between attacks the symptoms might be minor or the patient may even be symptom free, however it can be difficult to successfully treat.
Chronic prostatitis/chronic pelvic pain syndrome:
Most cases of prostatitis fall into this category, however it is the least understood. It can be further characterized as inflammatory or noninflammatory, depending upon the presence or absence of infection-fighting cells in the urine, semen, and prostatic fluid. Often no specific cause can be identified. The symptoms can come and go or remain chronically.
Asymptomatic inflammatory prostatitis:
This condition is often diagnosed incidentally during the work-up for infertility or prostate cancer. Individuals with this form of prostatitis will not complain of symptoms or discomfort, but they will have the presence of infection-fighting cells present in semen/prostatic fluid.

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