The term prostatitis actually encompasses four disorders:
Acute bacterial prostatitis is the least common of the four types but also the easiest to diagnose and treat effectively. Men with this disease often have chills, fever, pain in the lower back and genital area, urinary frequency and urgency often at night, burning or painful urination, body aches, and a demonstrable infection of the urinary tract as evidenced by white blood cells and bacteria in the urine.
Chronic bacterial prostatitis, also relatively uncommon, is acute prostatitis associated with an underlying defect in the prostate, which becomes a focal point for bacterial persistence in the urinary tract.
Chronic prostatitis/chronic pelvic pain syndrome is the most common but least understood form of prostatitis. It is found in men of any age, its symptoms go away and then return without warning, and it may be inflammatory or noninflammatory. In the inflammatory form, urine, semen, and other fluids from the prostate show no evidence of a known infecting organism but do contain the kinds of cells the body usually produces to fight infection. In the noninflammatory form, no evidence of inflammation, including infection-fighting cells, is present.
Asymptomatic inflammatory prostatitis is the diagnosis when the patient does not complain of pain or discomfort but has infection-fighting cells in his semen. Doctors usually find this form of prostatitis when looking for causes of infertility or testing for prostate cancer.
Sources
National Kidney and Urologic Diseases Information Clearinghouse