Hematuria is a medical term for blood in the urine. Hematuria can originate from anywhere along the urinary tract, including the kidney, ureter (the pipe drains urine from the kidney to the bladder), the bladder, or from the urethra (connecting the bladder to the outside of the body).
There are two types of hematuria:
- Gross hematuria is the visible presence of blood in the urine that can range in color from pink, bright red to coca-colored. It takes very little blood to produce red urine.
- Microscopic hematuria is blood in the urine that is only visible under microscope. It usually is picked up in your child’s pediatrician’s office during well-child visits.
There are many conditions that can cause hematuria but in general there are two categories: glomerular or non-glomerular disease.
The kidneys are essentially a filtering system. When conditions disrupt the integrity of the filters, so called glomeruli, blood can leak into the urine, either due to inflammation or congenital defects. Those include any type of glomerulonephritis (inflammation of the filters), most common for children are IgA nephropathy, poststreptococcal glomerulonephritis (following strep infection as the name suggests), Henoch-Schönlein purpura (HSP) glomerulonephritis, Lupus nephritis, heriditary nephritis (aka Alport syndrome), as well as a benign inherited condition called thin basement membrane disease that runs in the family.
Blood originating from outside of filters along the rest of the urinary tract is non-glomerular. Those conditions include kidney stones or crystals in the urine (more common than stones), urinary tract infection (UTI) by either bacteria or certain virus, cystic kidney diseases with spontaneous cystic rupture, or simply by trauma. Tumor or malformation of blood vessels also can cause hematuria but are extremely rare in children.
A patient with hematuria can be otherwise completely asymptomatic. However, sometimes it can be painful (flank, groin, abdominal, or during urination). Your child may also experience fever, headaches, nausea, vomiting, rash or joint pain or swelling, depending on the underlying cause.
For all patients referred to our office for hematuria, urine will be collected and analyzed either in our office or the laboratory. If your child has not completed potty training yet, we usually can collect urine by attaching a urinary bag. For most of the patients seen in our clinic, we do not need to place a catheter to collect urine. Sometimes we will ask for a 24 hour urine and send it to special laboratory for conditions like kidney stones. Depending on the suspected causes, additional blood testing and/or imaging studies like an ultrasound are the most common ones we order. If glomerular bleeding is suspected, a kidney biopsy (link for renal biopsy) may be considered to help establish the diagnosis and to guide further treatment. For patients suspected for certain urologic conditions, referral may be made to our pediatric urology office for further evaluation.
The majority of causes of hematuria in children are benign and do not need specific treatment. It is often self-limited or resolves on its own. Treatment is based on the underlying causes. Certain glomerulonephritis do need treatment with immunosuppressants (medications that suppress the immune system). Steroids are usually the first line treatment but other immunosuppressants are often used to help control the inflammation of kidney filters to prevent irreversible damages or scarring before the patient develops advanced chronic kidney disease. For hematuria caused by urine crystals or kidney stones, the mainstay treatment is ample hydration, low sodium diet and avoidance of excessive vitamin supplements, etc., depending on the stone composition.