Benign prostatic hyperplasia (BPH), commonly referred to as an enlarged prostate, is the most common prostate problem for men older than age 50. BPH can cause lower urinary tract symptoms such as difficulty starting urination or a weak urine stream. If the symptoms are more than mildly bothersome and interfere with a man’s daily life, treatment options are available. However, other diseases can cause lower urinary tract symptoms similar to those of BPH. Therefore, a careful medical history, a physical examination, and laboratory tests are required to exclude conditions such as narrowing of the urethra (urethral stricture) and bladder disease.
Following are tests your doctor can use to help make the diagnosis:
Urinalysis. An examination of a urine sample under a microscope, urinalysis performed in all patients who have lower urinary tract symptoms. Urinalysis is often the only laboratory test needed when symptoms are mild and the medical history and physical examination suggest that there are no other abnormalities.
Urine culture. A urine culture (an attempt to grow and identify bacteria in a laboratory dish) is performed when a urinary tract infection is suspected. In the presence of severe or chronic symptoms of BPH, blood tests to detect abnormalities in creatinine, blood urea nitrogen, and hemoglobin are used to rule out the presence of kidney damage or anemia.
Prostate-specific antigen (PSA) test. A PSA is generally recommended. PSA values alone are not helpful in determining whether symptoms are due to BPH or prostate cancer because both conditions can cause elevated levels. However, knowing a man’s PSA level may help predict how rapidly hisprostate will increase in size over time and whether problems such as urinary retention are likely to occur.
The American Urological Association recommends a PSA test if the test result could change the management of urinary symptoms. For men without bothersome symptoms in whom no intervention is anticipated, whether or not to measure PSA should be an individual decision once the man understands the potential benefits and harms. However, for a man with bothersome symptoms, PSA testing is recommended prior to any intervention since the finding of prostate cancer could alter management of BPH.
Men who experience moderate to severe symptoms may benefit from one or more of the following special diagnostic tests:
Uroflowmetry. In this noninvasive test, a man urinates into an electronic device that measures the speed of his urine flow. The average urine flow rate for a man over age 45 is 12 mL per second. A slow flow rate suggests an obstruction of the urethra. If the flow rate is high, urethral obstruction is unlikely and therapy for BPE will not be effective in most instances.
Pressure-flow urodynamic studies. These studies measure bladder pressure during urination by placing a recording device into the bladder and often into the rectum. The difference in pressure between the bladder and the rectum indicates the pressure generated when the bladder muscle contracts. A high pressure accompanied by a low urine flow rate indicates urethral obstruction. A low pressure with a low urine flow rate signals an abnormality in the bladder itself, such as one related to a neurological disorder.
Imaging studies.In general, imaging studies are performed only in patients who have blood in their urine, a urinary tract infection, abnormal kidney function, previous urinary tract surgery, or a history of urinary tract stones.
Ultrasonography is the imaging study used most often in men with lower urinary tract symptoms. This imaging study involves pressing a microphone-sized device (transducer) onto the skin of the lower abdomen. As the device is passed over the area, it emits sound waves that reflect off the internal organs. The pattern of the reflected sound waves is used to create an image of each organ. Ultrasonography can be used to detect structural abnormalities in the kidneys or bladder, determine the amount of residual urine in the bladder, detect the presence of bladder stones, and estimate the size of the prostate.
Cystoscopy. In this procedure, a cystoscope (a small lighted viewing device) is passed through the urethra into the bladder to directly view the two structures. Typically, cystoscopy is performed before prostate surgery to guide the surgeon in performing the procedure. Cystoscopy can also help the surgeon spot abnormalities of the urethra or bladder.