A 63-year-old man comes to the office due to poor urine flow for several months. The patient says that it takes about 10 seconds to initiate a urinary stream. He also needs to strain when urinating or the stream just stops before his bladder is empty. He has tried behavioral modifications, but the symptoms continue to be bothersome. The patient takes lisinopril for hypertension. He has smoked a pack of cigarettes a day for 30 years. His father had urothelial cancer of the bladder. He reports significant improvement several months after starting finasteride. A therapeutic effect on which of the following structures is most likely responsible for this patient's symptomatic improvement?

Question

A 63-year-old man comes to the office due to poor urine flow for several months.  The patient says that it takes about 10 seconds to initiate a urinary stream.  He also needs to strain when urinating or the stream just stops before his bladder is empty.  He has tried behavioral modifications, but the symptoms continue to be bothersome.  The patient takes lisinopril for hypertension.  He has smoked a pack of cigarettes a day for 30 years.  His father had urothelial cancer of the bladder.  He reports significant improvement several months after starting finasteride.  A therapeutic effect on which of the following structures is most likely responsible for this patient's symptomatic improvement?

Quizplus · Accepted Answer

11ec160b_358d_a7a1_9249_97f52eb475ec_MD0001_00 This patient has signs of bladder outlet obstruction (eg, urinary hesitancy, need to strain) most likely due to benign prostatic hyperplasia (BPH), a condition that is present in >90% of men age >80. The diagnosis is based on history of urinary symptoms and digital rectal examination showing a smooth, homogenously enlarged prostate. The prostate is located just anterior to the anal canal (Choice D) and posterior to the symphysis pubis (the above CT image is just superior to the joining of the left and right pubic bones). BPH may cause static urinary obstruction (androgen-mediated enlargement of the prostate) or dynamic obstruction (prostate smooth muscle contraction via α-adrenoceptors). 5-α reductase inhibitors (eg, finasteride) inhibit the action of androgens on the prostate gland, preventing the conversion of testosterone to dihydrotestosterone and thereby limiting further prostate enlargement. α-adrenergic blockers (eg, tamsulosin) relax the smooth muscle in the bladder neck and prostate gland and are also used to control symptoms of BPH. (Choice B) The distal end of the anterior bladder wall may or may not be visible at this level depending on patient positioning and bladder filling. Educational objective: The prostate is located between the pubic symphysis and the anal canal and is visible on inferior sections of the pelvis on CT scan. Benign prostatic hyperplasia is a common, age-related condition that causes urinary symptoms (eg, hesitancy, straining, incomplete voiding). It can be medically treated with α-adrenergic blockers and 5-α reductase inhibitors. __________ References: Drugs for benign prostatic hypertrophy (http://www.ncbi.nlm.nih.gov/pubmed/30410211) Pathophysiology of benign prostatic hyperplasia: insights from medical therapy for the disease. (http://www.ncbi.nlm.nih.gov/pubmed/20126609)

A 63-Year-Old Man Comes to the Office Due to Poor