A 67-year-old man shows up in the emergency department because he has not been able to void for the past 12 hours

A 67-year-old man shows up in the emergency department because he has not been able to void for the past 12 hours. He feels the need to, but he cannot do it. He gives a history that, for several years now, he has been getting up four or five times a night to urinate. It would take him a considerable time to get the urinary stream going, and the stream lacked force and often ended in a dribble. Because of a cold, 2 days ago he began taking an antihistamine, taking a decongestant, and drinking plenty of fluids. Physical examination shows a palpable, smooth, round mass arising from the pubis and reaching about half way toward the umbilicus. The mass is dull to percussion, and pushing on it accentuates the feeling of needing to void. Rectal examination reveals a large, boggy, non-tender prostate gland without nodules. This a classic presentation for which of the following acute conditions?

A. Bacterial prostatitis
B. Cystitis in a patient with bladder cancer
C. Renal failure
D. Urinary retention in a patient with benign prostatic hypertrophy
E. Urinary retention in a patient with prostatic cancer

Explanation: The correct answer is D. The history and rectal examination findings are classic for benign prostatic hypertrophy. The use of a decongestant has led to stimulation of alpha adrenergic receptors, which have further closed the bladder neck. A big, palpable bladder has resulted. Bacterial prostatitis (choice A) would produce pain, fever, and a very tender prostate on rectal examination. Cystitis and bladder cancer (choice B) could be expected to produce irritative symptoms and hematuria, but not painless retention. Renal failure (choice C) produces oliguria,
not anuria. The bladder would be empty and thus not palpable. The patient would urinate small amounts and feel no need to urinate more. Prostatic cancer (choice E) is usually first felt as a stony hard nodule. It would be unusual for it to grow to a size at which complete obstruction is the first manifestation. If it did, though, the prostate would feel stony hard.