Hematuria or “Haematuria” is the presence of frank blood or red blood cells in the urine. Urine does not present with blood because it is filtered through the kidney and the entire urinary tract (kidney, ureter and bladder). The urinary tract works together to remove the wastes but does not allow the blood to leak into the urine. I wanted today to review the causes of Hematuria.

At first, we have to consider two types of hematuria.: a microscopic hematuria where blood can only be seen through a microscope or in a laboratory setting and a gross hematuria when the urine color appears to be red, brown or be-colored due to the presence of blood. The blood may enter at any level in the urinary tract, including the kidneys and ureters, the bladder, the urethra and even the prostate in men.

Common causes of hematuria include urinary tract infections (UTI), Kidney stones, bladder cancer, viral illness and even exercises. Often, we will group the causes in glomerular or non-glomerular causes. Not all red urine van be called hematuria. Substances like blackberries food dyes and beets will color the urine in red. Women menstruations may also give the impression of a hematuria and also present with a positive dipstick test for urine. Myoglobin in the urine can also give the impression of hematuria in athletes by example with myoglobinuria. This protein is secreted into the urine when the phenomenon of rhabdomyolysis is seen. For a. hematuria to be detected, a positive urine dipstick test should confirm the presence of blood on high power field. If a hematuria is detected further evaluation through a history and physical examination with proper lab testing can help finding the underlying causes.

Hematuria can be classified in relation to its anatomical origin or to the timing, in relation to the anatomical origin. Red blood cell can enter and mix the urine at many anatomical areas in the urinary system (Kidney, Ureter, Bladder, urethra and prostate) in men but additionally with menstruation in women. Additionally, menstruation in women can mimic blood in the urine with a positive urine dipstick test for hematuria.

The causes can be related to the anatomical locations referring to the glomerulus of the kidney (Glomerular or Non-glomerular) which can be divided into upper urinary tract and lower urinary tract.im terms of the timing during urination. Hematuria can be initial, or terminal or even total which mean at onset of urination. A delayed hematuria suggests a more proximal bleeding site in the urinary tract while a hematuria at the onset or during the mid-stream signify a more distal origin. Hematuria throughout urination suggest that the site of bleeding is above the level of bladder. This is important to differentiate the site of bleeding to facilitate further treatment. Also, microscopic Hematuria can be obvious or macroscopic or occult and microscopic requiring a deep stick test.

Let us review different type of hematuria:

1-    Glomerular Hematuria is seen with IgA nephropathy, Hereditary Nephritis (Alport Disease), Hemolytic uremic syndrome, Port-infectious glomerulonephritis (Group B Streptococcus), membranoproliferative glomerulonephritis, lupus nephritis, Henoch Schoenlein purpura, nephritic syndrome, nephrotic syndrome, Polycystic kidney disease, Idiopathic hematuria.

2-    Non-glomerular hematuria: with visible clots in the urine. Seen with urinary tract infection (pyelonephritis, cystitis, prostatitis and urethritis, kidney stones, Cancer in kidney, bladder or prostate, benign prostatic hyperplasia, urinary stricture, renal papillary necrosis, trauma, Excessive exercises, Vitamin K deficiency, Sickle cell disease, medications like blood thinners.

3-    Mimickers of hematuria like Pigmenturia from certain medications like Phenazopyridine, Nitrofurantoin, Doxorubicin, Rifampicin and foods like blackberries, beets, dyes, rhubarb, fava beans with a false positive urine deep stick. The urine dipstick nay also be falsely negative for hematuria due to other substances in the urine. Generally, it will recognize the heme in the red blood cells as well as the free hemoglobin and myoglobin after hemolysis (rhabdomyolysis), A true positive dipstick does not always mean blood in the urine.

A visible or massive hematuria must be investigated as it may be of a pathologic cause. Urological cancer in the kidney or bladder are discovered in a quarter of cases. Any isolated hematuria should raise a suspicion for malignancy and should be investigated. Physical examination, blood pressure and blood work should assess the patient. With the hematuria blood work, urine analysis, cystoscopy, CT, MRI, IVP should be perform.

To confirm a new hematuria when evaluating a brown or red urine, we need to start with a urine analysis and a urine microscopy where hematuria will be defined by the presence of two to three red blood cells in the urine. With visualization under high power field, it will be important to know about any recent trauma, menstruations, urologic procedures, urinary tract infections. If there is hematuria with proteinuria, or red blood cast a consultation to a nephrologist may be needed. A non-glomerular origin of the hematuria may require a microbiological culture of the urine. If an infection is confirmed treatment need to be implemented until the urine culture become negative. If the hematuria persists a CT urogram and cystoscopy should be ordered. Complete blood count to assess for anemia is also expected.

In the case of a microscopic hematuria, detected by urine analysis or urine microscopy, Benign causes should be ruled out like urinary tract infection, viral illness, kidney stones, exercises, menses, trauma or recent urologic procedures. Once theses causes are ruled out, we will need to think about Genitourinary malignancies in a tobacco smoker and depending on the number of red blood cells per high power field. (3-10 cells, 11-25 cells. Or more than 25 cells) than cystoscopy and renal ultrasound to a CT urogram should be performed. If a cause can’t be found to explained, a consultation to a nephrologist is advised.

A hematuria can often be explained by damage to the structures of the urinary system9Kidney, ureter, bladder, urethra, prostate especially the glomerular basement membrane or the chemical or mechanical erosion of the membrane of the mucosal surface of the genitourinary tract. Emergent situation like in the case of an Acute clot Retention, Emergency Medical treatment with a Toomey syringe, instilling saline or to draw back urine from the bladder in order to evacuate the blood clots. This procedure can be repeated as often it is needed. Remaining blood clots in the bladder will be digested by the enzyme urinary urokinase which will produce fibrin pigments. An indwelling catheter (22-24 French) will also prevent the obstruction. Occasionally a continuous three-way catheter can be inserted in spite of a Foley to perform a bladder irrigation. Finally, an emergent cystoscopy may be necessary if the bleeding remain uncontrollable. Blood transfusion and the correction of any co-existing coagulopathy should be corrected.

In 25% of the cases, there is an urosepsis caused by a urological tract infection as a result of a systemic inflammatory response with fever, tachycardia, leukocytosis, hypothermia. Patient may experience flank pain, urinary retention, scrotal pain, pain at micturition, costovertebral angle tenderness, gross hematuria with a red or brown urine, or microscopic hematuria. Imaging test, antibiotics and intravenous fluids may become unsuccessful at time and the need for vasopressor medication and the placement of a central venous line (CVP) may be required.

Microscopic hematuria is prevalent in the third of patient suffering from the problem. With a history of heavy smoking, people older than 60 are prone for the disease while less than 3% of patients with hematuria will have urologic malignancy. Routine screening is not recommended because of individuals going to repeated testing develop a higher rate of urologic malignancies. Males older than 35 with current or previous smoking history, or exposed to benzenes or aromatic amines or pelvic radiation therapy have an increase in risk factor. In the pediatric population, there is a prevalence of 2% in which 5% of children has microscopic hematuria but 40% with macroscopic hematuria, have a cancer diagnosis. Other common causes in children are fever, strenuous exercises, acute nephritis, multicystic dysplastic kidney, urinary stones, coagulopathies, telangiectasia. vascular thrombosis, Sickle cell, and any other congenital syndrome like Alport syndrome etc.

Maxime Coles MD

Boca Raton FL


1-    Papadakis, Maxime A, McPhee, Stephen J. Rabow, Michael W: “Current medical diagnosis and treatment 2022, 23-02 Hematuria

2-    McAninch, Jack W, Lue, Tom (2013): Symptoms of Disorders of the Genitourinary Tract” Chapter 3: Symptoms of Disorders of the Genitourinary tract”. Smith and Tanagho’s General Urology: Diagnosis and Management of Hematuria

3-    Avellino Gabriella J; Bose Sanchita, Wang David S (June 2016) Surgical clinics of North America. 96 (3) pp 503-515.

4-Yun, Edward J, Meng, Maxwell V, Carroll, Peter, (Mach 2004) “Evaluation of

the Patient with hematuria”: Medical Clinics of North America 88 (2) pp 329-343.

4-    Cohen, Robert A; Brown, Robert S, (2003-06-05). “Clinical practice: Microscopic hematuria”. The new England Journal of Medecine. 348 (23): pp 2330-2338.

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