The patient is treated with antibiotics, but symptoms recur one week after antibiotic therapy is stopped

A 45-year-old man consults a physician because of dysuria. The patient is treated with antibiotics, but symptoms recur one week after antibiotic therapy is stopped. A different antibiotic is tried, but symptoms again recur after cessation of the antibiotic. Rectal examination demonstrates an enlarged prostate with areas of tenderness and fluctuance. Which of the following is the most likely diagnosis?

A. Benign prostatic hyperplasia
B. Chronic nonbacterial prostatitis
C. Prostadynia
D. Prostatic abscess
E. Prostatic carcinoma

Explanation: The correct answer is D. The patient has a prostatic abscess. The typical age is 40 to 60 years, and is consequently somewhat younger than the ages at which benign prostatic hyperplasia and prostate cancer become major problems. Infecting organisms include aerobic gram-negative bacilli and Staphylococcus aureus. Prostatic abscess should be suspected when a man develops repeated urinary tract infections that seem to get better with antibiotic therapy, only to recur later. The most important diagnostic clue, if detectable, is the presence of a fluctuant mass in the prostate on rectal exam. Some patients have only prostatic enlargement, or even no positive findings on physical examination. Patients may have normal urine, although it is more usual for an organism to be cultured at some point. Prostatic ultrasound may be helpful if the diagnosis is suspected. A few cases are even picked up at the time of prostatic resection for benign prostatic hyperplasia or other disease. Treatment is with evacuation of the abscess by a transurethral or perineal route followed by appropriate antibiotics.

Benign prostatic hyperplasia (choice A) can cause urinary obstruction predisposing for bladder infection, but the prostate would not be fluctuant.

Chronic nonbacterial prostatitis (choice B) can cause symptoms resembling urinary tract infection, but would not cause a fluctuant prostate.

Prostadynia (choice C) is a noninfectious, noninflammatory condition of younger men that can mimic prostatitis, but would not cause a fluctuant prostate.

Prostatic carcinoma (choice E) is usually asymptomatic, and can cause a firm prostatic mass.