What is blood in the urine?
Blood in the urine is something that always needs to be tested. We call it haematuria, and probably the most important thing that we need to rule out, when a patient presents with that, is any sort of cancer that might be affecting the urinary tract. So that might be anything from the kidney right down to the urethra. So one of the commonest of course is kidney cancer, but you can get cancer arising in the bladder, or in fact any lining of the urinary tract along the whole way. Prostate cancer rarely presents with blood in the urine, but can.
So they’re really the main diagnoses that we need to rule out. Now sometimes however you can get blood in the urine with a cluster of other symptoms, such as painful urination, or a fever. In that situation, that’s very different because that’s far more likely to be due to an infection, or a urinary tract infection. But when we see blood in the urine, without those other infective symptoms, we must rule out any sort of cancer.
Another potential cause of blood in the urine, can be kidney disease. So the actual filtering systems within the kidney, the glomeruli, can sometimes bleed and you can have a condition called, glomerulonephritis, and that needs to be treated as well. Blood in the urine, or haematuria, can either be visible, what we call, gross haematuria to the patient and that’s what they present with, or they might have had a urine test done for whatever reason, and blood cells had been found under the microscope. So that’s microscopic haematuria.
What are the differences?
They’re really quite different in terms of their clinical importance. Microscopic haematuria is actually not that uncommon, again we still need to rule out any underlying disease, but sometimes we’ll see very small elevations of red blood cells in the urine, which turn out to be nothing at all. But our job as urologists is certainly to diagnose if there is any sinister cause of that blood in the urine. The first test for blood in the urine is of course a urine test. If the patient is presenting to the GP for example, with blood in the urine, then the GP will test that urine, to confirm that there are red blood cells, but also to rule out potentially any infection. Sometimes the actual shape of the red blood cells under the microscope can also give us clues as to what the diagnosis might be.
For example, if the shape has been altered of the red blood cells, then it’s more likely to be due to disease of the filters within the kidney. But if the shape has not changed then it may be more likely to be due to a tumour, such as a kidney cancer for example. You can have episodes when you see blood in the urine, and it’s quite obviously red, and then a few days later you might get a urine test and actually have no red blood cells in there at all. I think it’s important that if that occurs to actually not to be re-assured by that.
I’ll give you an example, if a patient has a tumour in the bladder for example, then it might bleed one day, and cause blood in the urine that you can see, and then stop bleeding a few days later, and if it stops bleeding, it hasn’t gone away, it’s just stopped bleeding.
So if a patient has blood in the urine and then it stops, they must still see a doctor, and they must be investigated. The tests for blood in the urine once you’ve actually tested the urine, are imaging, that might take the form of a urinary tract ultrasound, a totally non-invasive test which can look at the kidneys, and the bladder, and also assess the prostate in men. However if there is nothing found on that but there’s even more suspicion, then sometimes we’ll get a CT scan which is much more sensitive at picking up smaller tumours for example. And when we do that CT scan the patient will be injected with some contrast into the vein, and that contrast or dye will then be filtered by the kidneys, and lining up that urinary tract system so that we can get a really good picture.
The other test that needs to be done is what’s called a cystoscopy, which is us looking inside the bladder, with a scope, because sometimes you can get a very small or flat lesion arising from the bladder, such as a flat bladder cancer, that you can’t actually see on imaging. So we have to directly eyeball it with a scope. There are also some other urine tests that we’ll occasionally do, which are not just confirming for whether there’s blood in it or not, but actually looking for abnormal, or cancer cells within the urine, that’s called urine cytology.
And if we do that we’ll often get 3 of them because the shedding of tumour cells from a tumour within the urinary tract is quite intermittent. For example, if we just did one of those then the tumour might not be shedding any of it’s cancer cells that day, so we tend to get them on different days.