Impotence/Erectile Dysfunction (cont.)
What Specialized Tests Do Doctors Use to Investigate Erectile Dysfunction?
- Laboratory testing: Laboratory testing is not necessary for all men, rather it will depend on your symptoms, physical examination and medical history.
- If laboratory tests are performed, they would normally start with an evaluation of your hormone status (testosterone or male hormone), particularly if one of your symptoms is low sexual desire (low libido). Blood tests for testosterone should ideally be taken early in the morning because that's when levels are usually at their highest. It is recommended that if the first testosterone level is low to repeat it as testosterone levels can vary. If the testosterone level is low, other blood tests, such a luteinizing hormone and prolactin, can help determine if there is a problem with the pituitary gland.
- Your blood may be checked for glucose, cholesterol, thyroid function, triglycerides, lipid/cholesterol profile if these blood tests have not already been obtained and your evaluation suggests risk factors. A prostate-specific antigen (PSA) level may be obtained if your physician is considering the use of testosterone therapy.
- A urinalysis looking for blood cells, protein, and glucose (sugar) may also be done.
- Imaging: An ultrasound may be performed but is not commonly obtained in the initial evaluation and management of erectile dysfunction.
- A duplex ultrasound is a diagnostic technique that uses painless, high frequency sound waves to visualize structures beneath the skin's surface. The principle is similar to the sonar used on submarines. Sound waves are reflected back when they contact relatively dense structures such as fibrous tissue or blood vessel walls. These reflected sound waves can be converted into pictures of the internal structures being studied.
- This procedure is usually performed before and after injection of a smooth-muscle-relaxing medication into the penis, which normally should significantly increase the diameter of the penile arteries. The procedure itself is painless. Duplex ultrasonography is most useful in evaluating possible penile arterial disorders, but in those individuals considering surgery for problems with the arteries to the penis, a more invasive study, angiogram, is needed to identify the location of the damaged artery.
- Nocturnal penile tumescence testing (NPT) may be useful in distinguishing mental from physical impotence. This test involves the placement of a band around the penis that you would wear during two or three successive nights. If an erection occurs, which is expected during rapid eye movement (REM) sleep, the force and duration are measured on a graph. Inadequate or no erections during sleep suggests an organic or physical problem, while a normal result may indicate a high likelihood of emotional, psychological, or mental causes.
- Formal neurological testing is not needed for most men. But anyone with a history of nervous system problems, such as loss of sensation in the arms or legs, and those with a history of diabetes may be asked to undergo testing. This could include an MRI imaging of the spine or electro-conductive studies to assess nerve distribution and function.
- The sensitivity of the skin of the penis to detect vibrations (biothesiometry) can be used as a simple office nerve function screening test. This involves the use of a small vibrating test probe placed on the right and left side of the penile shaft as well as on the head of the penis. The strength of the vibrations is increased until you can feel the probe vibrating clearly. Although this test does not directly measure the erectile nerves, it serves as a reasonable screening for possible sensory loss and is simple to perform. More formal nerve conduction studies are only performed in selected cases.
Medically Reviewed by a Doctor on 9/11/2017
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