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Bloody Urine and Hematuria

Microscopic hematuria is defined as more than five red blood cells per high power field, or more than 20 red blood cells per milliliter blood in the urine. But the important thing is that you repeat the sample two or three times before actually defining hematuria, because a lot of times on the repeat sample the hematuria goes away. So the repeat samples are important in starting the whole evaluation of hematuria in kids. There are some causes of change of color of urine to red, pink, orange, blue … blue, no, brown that are not necessarily real hematuria, and those are important to remember. And those are important to remember in case there is some condition that leads to it, like something called "brick dust diaper."

There are some conditions that lead to transient hematuria. It is true hematuria but not permanent. It goes away after about 48 hours of having these conditions corrected, such as high fevers, dehydration and exercise. I think you all know that runners and pole vaulters and other athletes have hematuria a lot a times that is transient. So those are important to remember.

Now it would be nice if once we have diagnosed hematuria, microscopic hematuria mainly but also growth hematuria, if we could have real clear knowledge of where it’s coming from right off the bat. Upper tract or lower tract? It would help us to tailor our workup to a much narrower workup. However, unfortunately there is no clear-cut defining feature that says it’s coming from the upper tract or the lower tract. However, we do use some clues for localizing and those clues are; for glomerular origin.

As we are seeing the patient for the first time, taking the history, taking the physical exam, already we have to have a list of possible causes going through our minds in order to ask the right questions, to look for the correct things on physical exam. So things that should be starting to go through our mind, we can go by level. From glomerular to lower tract. So glomerular, all the glomerular nephritides, which are very very many. There are those that are more common and those that are less common. The most common acute glomerulonephritis, as you all know, is the post-infectious one which is usually post-strep but not always. Every infection, almost, in the world has been described with acute glomerulonephritis.

I’ll talk in more detail about the different glomerulonephritides after the hematuria, proteinuria. So I’m not going into every detail about these diseases right now. The other common condition in kids are Henoch-Schonlein purpura, which is in some respects another condition on the spectrum of IgA nephropathy, but has not only the hematuria and proteinuria but also the skin manifestations, joint manifestations, abdominal pain, etc. Systemic lupus is a very common systemic disease with nephritis.

Then, going down, non-glomeruli bacilli in the kidney can be from the interstitium, such as infections or drugs, the most common are ampicillin, the penicillin family are the most common causes of interstitial nephritis. With protein, but also with hematuria it can be. And nephrocalcinosis, which is just deposits of calcium in the kidney, not necessarily stones, but deposition of calcium in the pyramid so that it looks like a whitish area on the ultrasound. It’s a common cause of hematuria in kids, in babies. Especially in babies that have gotten Lasix and others.

Other causes of renal but non-glomerular are acute tubular necrosis. A baby who had at birth asphyxia or some sort of surgery and had some sort of - even a short period time - of less than adequate blood supply to the kidneys. That’s anything like that. Shock or whatever can cause ATN, blood in the urine. Vascular causes, especially in babies, are renal vein and artery thrombosis; babies of diabetic mothers, that’s the most common cause of renal vein thrombosis, IVN. But renal arteries thrombosis from lines in the umbilical artery and other causes. That’s what’s mentioned here. Premature infant with RDS and intubated for a long time will have lines in the umbilical veins and arteries and can thrombose or emboli. Baby shunts are not common in kids but can be a cause of hematuria. A lot of times we cause an AV shunt with a biopsy, for instance. Not a lot of times but it can happen. Hemangiomata usually are a part of another syndrome, such as tuberous sclerosis or something that has hemangiomata as a basic finding. So it’s not very common as a single cause of hematuria.

Still in the kidney, cystic diseases are very commonly associated with hematuria. Sometimes that’s how you find that a family has a polycystic kidney. Hypertension, family history, is very commonly associated with cystic disease. Tumors. The most common, as you all know, Wilms tumor. That’s one that we dread, with an abdominal mass, hematuria, lot of times mothers find this in the bathtub. But other tumors are not so common in kids. There is, obviously, other tumors that could also involve the kidney.

Other causes lower down; any congenital anomalies such as even hydronephrosis or any obstruction causing some hydronephrosis, hydroureter. All these causes of obstruction don’t really need a lot of trauma, or any trauma that you know of, and can cause a hematuria. So you can find all of a sudden a surprise on an ultrasound when you do a workup of hematuria. That’s why ultrasound would be one of the first things to do. We’ll talk about the workup in a minute. Lithiasis anywhere along the line, from kidney to urethra really, can cause hematuria and trauma. Trauma is difficult with kids.