Blood in the Urine: Uroradiologic Imaging
Guest: Dr. Nancy Curry – Radiology, MUSC
Host: Dr. Linda Austin – Psychiatry, MUSC
Dr. Linda Austin: I’m Dr. Linda Austin. I’m interviewing Dr. Nancy Curry, who is Professor of Radiology, with a specialization in uroradiology. In fact, Dr. Curry is the only uroradiologist in the state of South Carolina. So, we’re fortunate to have you here, Dr. Curry. Today, we’re going to be talking, first, about blood in the urine, or hematuria. Dr. Curry, if a person notices that their urine is darker than normal, if their urine looks more like tea, for example, is it something to be concerned about?
Dr. Nancy Curry: It’s definitely very alarming for somebody to notice that there’s potentially blood in the urine. Not all red urine, though, is due to blood. For instance, there are certain medications and certain food materials that can be processed by the body differently in some individuals, and actually produce a red-looking urine. Medications that can change the color of urine include such things as urinary antiseptics or analgesics. There can also be food materials, like rhubarb and beets, that can turn the urine a distinctive color in some individuals.
So, what may be in the urine is a pigment, rather than blood cells. The only way to know if there’s truly blood in the urine is for a physician to take a urine sample and look specifically for red blood cells. If there are only red blood cells, and not other things, like white blood cells or protein, that’s where imaging comes into play.
Dr. Linda Austin: And, why is that? If there were white blood cells, what would that indicate to a doctor?
Dr. Nancy Curry: Probably the most common reason for blood in the urine is if someone has a urinary tract infection. So, the first thing the physician would want to know is: does the patient have burning with urination, difficulty urinating? And that’s usually a very easy diagnosis to make, and doesn’t require any sort of imaging. It’s probably most common in young females. In an older male, the problem may well be an enlarged prostate gland. But, again, there are other manifestations that would alert the physician that this may be the problem.
At any rate, the key thing is to get a sample of the urine and determine that there truly are red cells in the urine. If that’s the case, and there is no strong element of protein or other findings in the urine that would suggest that there’s some form of medical renal disease, then, imaging is appropriate. In the past, there were an awful lot of differing types of imaging that we could bring into the investigation of blood in the urine. We could do a standard radiograph of the abdomen; a standard x-ray, and look to see if the patient had stone disease. Stones that lie within the kidney or within the bladder can scratch the surface of the inside of those structures enough so that they will bleed enough to show some blood in the urine.
Unfortunately, plain x-rays of the abdomen aren’t sensitive enough to identify small stones, or stones that are composed of certain types of elements. Ultrasound is another variety of imaging that can be used. It can determine whether there’s any obstruction of the kidney, whether there are any masses in the kidney, and whether there’s anything around the kidney which could be important to know about. But, unfortunately, it doesn’t give a very precise image of what’s going in the urinary system.
When spiral CT, or helical CT, came into being and became refined with better imaging techniques; with multislice helical CT, which has come into its own as a magnificent imaging test in the past few years, there has been developed a way of investigating the entire urinary tract by one examination; the CT examination. It’s taken the place of standard radiography, followed by ultrasound, possibly followed by an IVP (intravenous pyelography), which is an old-fashioned way of evaluating the urinary system.
Dr. Linda Austin: So, if a patient comes in, then, with that complaint; the doctor thinks that they need to get a CT, what is the process, actually, from the patient’s point of view? How does that occur?
Dr. Nancy Curry: The nice thing about CT is that you don’t have to have a bowel preparation. The CT slices the body, so to speak, into thin sections; like a loaf of bread. Therefore, we’re seeing inside the body. We don’t have to look through distorting shadows created by gas within the bowel or overlying bones, or other overlying structures, that get in the way of seeing the kidneys or the ureters, or the bladder, which are the places where the blood is potentially coming from.
So, there’s no bowel prep. The patient doesn’t have to undergo any extensive preparation for the study. They do get an injection of a dye, which is a small needle shot that delivers the dye, or contrast material, into the vein, which then carries it throughout the body. It specifically ends up in the urinary tract, showing its anatomy very precisely, because the kidneys concentrate this dye and excrete it just as if it’s urine. In the process, we get to see the kidneys, the vascular system associated with the kidneys, the ureters, and the bladder.
Dr. Linda Austin: So, what are the typical causes, then, of blood in the urine that the CT scan might reveal to you?
Dr. Nancy Curry: The blood might be coming anywhere from the top of the kidneys to below the bladder, in the urethra. So, there’s a lot of anatomy that needs to be examined. And the beauty of what we call CT urography is that we can, in one examination, examine all elements of the urinary tract, to see if there’s some anatomic abnormality that is creating the problem, for instance, stones, tumors, obstructive processes; things that are blocking the urinary system.
Dr. Linda Austin: Such as?
Dr. Nancy Curry: Tumors of the ureter, strictures involving the narrowings of the ureter that prevent the flow of urine getting past. And, interestingly, in some cases, the culprit is not the urinary system. It can actually arise in a structure nearby, such as inflammatory diseases or infectious diseases within the neighboring large bowel, for instance. Or, there can be gynecological processes, something having to do with a system that doesn’t involve the urinary system.
Dr. Linda Austin: Other can conditions can also cause it?
Dr. Nancy Curry: In many cases, blood in the urine does not have a specific source that we can pinpoint, even with this optimum method of imaging.
Dr. Linda Austin: Now, how would that be? Could there just be bleeding without a cause?
Dr. Nancy Curry: There are a number of possibilities. There are some people who have familial hematuria. This occurs for no particularly good reason, except that the interior microstructure of the kidney is a little leaky. It allows a little bit of the blood to leak through the plumbing, which is benign. But, unfortunately, it has to be worked up because there might be these more important processes that are occurring. There’s something called March hematuria, which is known to happen with people who do a lot of physical exercise.
Dr. Linda Austin: Like marching?
Dr. Nancy Curry: Like marching; described in Marines or troops who do a lot of marching around, and pounding, which creates the shedding of excess blood cells through this filter that the urinary system is. These are benign causes. But, again, they have to be distinguished from more important causes, like tumors of the kidneys, ureters, and bladder.
Dr. Linda Austin: So, even though it may prove to be nothing, you really have to walk through that whole process of finding out what it is, because there is the off chance that it could be something serious.
Dr. Nancy Curry: Provided, it’s not something simple like a urinary tract infection; which your doctor might want to diagnose and treat, and if the blood in the urine goes away, along with the other symptoms, then, imaging is probably not necessary: if you’re young, if you have no complicating factors; like smoking, or other predisposing conditions, for bladder or renal tumors.
Dr. Linda Austin: Dr. Curry, thanks for talking with us today.
Dr. Nancy Curry: Thank you very much.
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