Hematuria is red blood cells (RBCs) in urine, specifically > 3 RBCs per high-power field on urine sediment examination. Urine may be red, bloody, or cola-colored (gross hematuria with oxidation of blood retained in the bladder) or not visibly discolored (microscopic hematuria). Isolated hematuria is urinary RBCs without other urine abnormalities (eg, proteinuria Proteinuria Proteinuria is protein, usually albumin, in urine. High concentrations of protein cause frothy or sudsy urine. In many renal disorders, proteinuria occurs with other urinary abnormalities (eg... read more , casts).
Red urine is not always due to RBCs. Red or reddish brown discoloration may result from the following:
Hemoglobin or myoglobin in urine
Foods (eg, beets, rhubarb, sometimes food coloring)
Drugs (most commonly phenazopyridine, but sometimes cascara, diphenylhydantoin, methyldopa, phenacetin, phenindione, phenolphthalein, phenothiazine, and senna)
Pathophysiology of Isolated Hematuria
Red blood cells (RBCs) may enter urine from anywhere along the urinary tract—from the kidneys, collecting system and ureters, prostate, bladder, and urethra. In females, normal or abnormal uterine bleeding may be misdiagnosed as hematuria.
Etiology of Isolated Hematuria
Most cases involve transient microscopic hematuria that is self-limited and idiopathic. Transient microscopic hematuria is particularly common in children, present in up to 5% of their urine samples. There are numerous specific causes (see table Some Specific Causes of Hematuria Some Common Specific Causes of Hematuria ).
The most common specific causes differ somewhat by age, but overall the most common are
Congenital or acquired anatomic abnormalities
Cancers
Vigorous exercise may cause transient hematuria. Cancer and prostate disease are a concern mainly in patients > 50, although younger patients with risk factors may develop cancer.
Glomerular disorders can be a cause at all ages. Glomerular disorders Overview of Glomerular Disorders The hallmark of glomerular disorders is proteinuria, which is often in the nephrotic range (≥ 3 g/day). Glomerular disorders are classified based on urine changes as those that manifest predominantly... read more may represent a primary renal disorder (acquired or hereditary) or be secondary to many causes, including infections (eg, group A beta-hemolytic streptococcal infection), connective tissue disorders and vasculitis Overview of Vasculitis Vasculitis is inflammation of blood vessels, often with ischemia, necrosis, and organ inflammation. Vasculitis can affect any blood vessel—arteries, arterioles, veins, venules, or capillaries... read more (eg, systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more
[SLE] at all ages, immunoglobulin A–associated vasculitis Immunoglobulin A–Associated Vasculitis (IgAV) Immunoglobulin A–associated vasculitis (formerly called Henoch-Schönlein purpura) is vasculitis that affects primarily small vessels. It occurs most often in children. Common manifestations... read more
[Henoch-Schönlein purpura] in children), and blood disorders (eg, mixed cryoglobulinemia, serum sickness). Worldwide, IgA nephropathy Immunoglobulin A Nephropathy Immunoglobulin A (IgA) nephropathy is deposition of IgA immune complexes in glomeruli, manifesting as slowly progressive hematuria, proteinuria, and, often, renal insufficiency. Diagnosis is... read more
is the most common form of glomerulonephritis. Thin basement membrane disease and mild IgA nephropathy may cause isolated hematuria; however, most other glomerular causes of hematuria are accompanied by proteinuria.
Schistosoma haematobium, a parasitic fluke that causes significant disease in Africa (and, to a lesser extent, in India and parts of the Middle East), can invade the urinary tract, causing hematuria. Schistosomiasis Schistosomiasis Schistosomiasis is infection with blood flukes of the genus Schistosoma, which are acquired transcutaneously by swimming or wading in contaminated freshwater. The organisms infect the... read more is considered only if people have spent time in endemic areas. Mycobacterium tuberculosis may also infect the lower or upper urinary tract and cause hematuria, occasionally causing urethral strictures Urethral Stricture Urethral stricture is scarring that obstructs the anterior urethral lumen. Urethral stricture can be Congenital Acquired Anything that damages the urethral epithelium or corpus spongiosum can... read more .
Other causes of hematuria include
Urinary tract instrumentation or procedure (eg, Foley catheterization, prostate or kidney biopsy, lithotripsy)
Radiation cystitis
Drug-induced hemorrhagic cystitis
Vascular etiology—which is rare (eg, renal infarction, renal vein embolism, renal arteriovenous malformation)
Evaluation of Isolated Hematuria
History
History of present illness includes duration of hematuria and any previous episodes. Urinary obstructive symptoms (eg, incomplete emptying, nocturia, difficulty starting or stopping) and irritative symptoms (eg, irritation, urgency, frequency, dysuria) should be noted. Patients should be asked about the presence of pain and its location and severity and whether they have vigorously exercised.
Review of systems should seek symptoms of possible causes, including joint pain and rashes (connective tissue disorder), and hearing loss or ocular manifestations (hereditary nephritis Alport Syndrome Alport syndrome is a genetically heterogeneous disorder characterized by nephritic syndrome (ie, hematuria, proteinuria, hypertension, eventual renal insufficiency) often with sensorineural... read more , also called Alport syndrome). Presence of fever, night sweats, or weight loss should also be noted.
Past medical history should include questions about any recent infections, particularly a sore throat that may indicate a group A beta-hemolytic streptococcal infection. Conditions known to cause urinary tract bleeding (particularly kidney calculi Urinary Calculi Urinary calculi are solid particles in the urinary system. They may cause pain, nausea, vomiting, hematuria, and, possibly, chills and fever due to secondary infection. Diagnosis is based on... read more , sickle cell disease Sickle Cell Disease Sickle cell disease (a hemoglobinopathy) causes a chronic hemolytic anemia occurring almost exclusively in people with African ancestry. It is caused by homozygous inheritance of genes for hemoglobin... read more or trait, and glomerular disorders Overview of Glomerular Disorders The hallmark of glomerular disorders is proteinuria, which is often in the nephrotic range (≥ 3 g/day). Glomerular disorders are classified based on urine changes as those that manifest predominantly... read more ) should be sought, along with any history of congenital urinary tract anomalies Overview of Congenital Genitourinary Anomalies Congenital anatomic anomalies of the genitourinary tract are more common than those of any other organ system. Urinary tract anomalies predispose patients to many complications, including urinary... read more . Also, conditions that predispose to a glomerular disorder, such as a connective tissue disorder (particularly systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more
[SLE] and rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is a chronic systemic autoimmune disease that primarily involves the joints. Rheumatoid arthritis causes damage mediated by cytokines, chemokines, and metalloproteases.... read more
), endocarditis Infective Endocarditis Infective endocarditis is infection of the endocardium, usually with bacteria (commonly, streptococci or staphylococci) or fungi. It may cause fever, heart murmurs, petechiae, anemia, embolic... read more
, shunt infections, and abdominal abscesses Intra-Abdominal Abscesses Abscesses can occur anywhere in the abdomen and retroperitoneum. They mainly occur after surgery, trauma, or conditions involving abdominal infection and inflammation, particularly when peritonitis... read more
, should be identified. Risk factors for genitourinary (GU) cancer should be identified, including smoking (the most significant), drugs (eg, cyclophosphamide, phenacetin), and exposure to industrial chemicals (eg, nitrates, nitrilotriacetate, nitrites, trichloroethylene).
Family history should identify relatives with known polycystic kidney disease Autosomal Dominant Polycystic Kidney Disease (ADPKD) Polycystic kidney disease (PKD) is a hereditary disorder of renal cyst formation causing gradual enlargement of both kidneys, sometimes with progression to renal failure. Almost all forms are... read more , a glomerular disorder Overview of Glomerular Disorders The hallmark of glomerular disorders is proteinuria, which is often in the nephrotic range (≥ 3 g/day). Glomerular disorders are classified based on urine changes as those that manifest predominantly... read more , or GU cancer. Patients should be asked about travel to areas where schistosomiasis Schistosomiasis Schistosomiasis is infection with blood flukes of the genus Schistosoma, which are acquired transcutaneously by swimming or wading in contaminated freshwater. The organisms infect the... read more is endemic, and tuberculosis risk factors should be assessed. Drug history should note use of anticoagulants, antiplatelet drugs (although controlled anticoagulation itself does not cause hematuria), and heavy analgesic use.
Physical examination
Vital signs should be reviewed for fever and hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more .
The heart should be auscultated for murmurs (suggesting endocarditis Infective Endocarditis Infective endocarditis is infection of the endocardium, usually with bacteria (commonly, streptococci or staphylococci) or fungi. It may cause fever, heart murmurs, petechiae, anemia, embolic... read more ).
The abdomen should be palpated for masses; flanks should be percussed for tenderness over the kidneys. In men, a digital rectal examination should be done to check for prostate enlargement, nodules, and tenderness.
The face and extremities should be inspected for edema (suggesting a glomerular disorder), and the skin should be inspected for rashes (suggesting vasculitis Overview of Vasculitis Vasculitis is inflammation of blood vessels, often with ischemia, necrosis, and organ inflammation. Vasculitis can affect any blood vessel—arteries, arterioles, veins, venules, or capillaries... read more , SLE Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more
, or immunoglobulin A–associated vasculitis Immunoglobulin A–Associated Vasculitis (IgAV) Immunoglobulin A–associated vasculitis (formerly called Henoch-Schönlein purpura) is vasculitis that affects primarily small vessels. It occurs most often in children. Common manifestations... read more
).
Red flags
The following findings are of particular concern:
Gross hematuria and concurrent proteinuria
Persistent microscopic hematuria, especially in older patients
Age > 50
Hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more
and edema Edema Edema is swelling of soft tissues due to increased interstitial fluid. The fluid is predominantly water, but protein and cell-rich fluid can accumulate if there is infection or lymphatic obstruction... read more
Systemic symptoms (eg, fever, night sweats, weight loss)
Interpretation of findings
Clinical manifestations of the various causes overlap significantly, so urine and often blood tests are required. Depending on results, imaging tests may then be needed. However, some clinical findings provide helpful clues (see table Some Common Causes of Hematuria Some Common Specific Causes of Hematuria ).
Blood clots in urine essentially rule out a glomerular disorder. Glomerular disorders are often accompanied by edema, hypertension, or both; symptoms may be preceded by an infection (particularly a group A beta-hemolytic streptococcal infection in children).
Calculi usually manifest with excruciating, colicky pain. Less severe, more continuous pain is more likely to result from infection, cancer, polycystic kidney disease Autosomal Dominant Polycystic Kidney Disease (ADPKD) Polycystic kidney disease (PKD) is a hereditary disorder of renal cyst formation causing gradual enlargement of both kidneys, sometimes with progression to renal failure. Almost all forms are... read more
, glomerulonephritis Overview of Nephritic Syndrome Nephritic syndrome is defined by hematuria, variable degrees of proteinuria, usually dysmorphic red blood cells (RBCs), and often RBC casts on microscopic examination of urinary sediment. Often... read more , and loin pain–hematuria syndrome.
Urinary irritative symptoms suggest bladder or prostate infection but may accompany certain cancers (mainly bladder and prostate).
Urinary obstructive symptoms usually suggest prostate disease.
An abdominal mass suggests polycystic kidney disease or renal cell carcinoma Renal Cell Carcinoma Renal cell carcinoma (RCC) is the most common renal cancer. Symptoms can include hematuria, flank pain, a palpable mass, and fever of unknown origin (FUO). However, symptoms are often absent... read more
.
A family history of nephritis, sickle cell disease Sickle Cell Disease Sickle cell disease (a hemoglobinopathy) causes a chronic hemolytic anemia occurring almost exclusively in people with African ancestry. It is caused by homozygous inheritance of genes for hemoglobin... read more
or trait, or polycystic kidney disease suggests that as a cause.
Travel to Africa, the Middle East, or India suggests the possibility of schistosomiasis Schistosomiasis Schistosomiasis is infection with blood flukes of the genus Schistosoma, which are acquired transcutaneously by swimming or wading in contaminated freshwater. The organisms infect the... read more .
Systemic symptoms (eg, fever, night sweats, weight loss) may indicate cancer or subacute infection (eg, tuberculosis [TB]) or an autoimmune (connective tissue) disorder.
On the other hand, some common findings (eg, prostate enlargement, excessive anticoagulation), although potential causes of hematuria, should not be assumed to be the cause without further evaluation.
Testing
Before testing proceeds, true hematuria should be distinguished from red urine by urinalysis. In women with vaginal bleeding, the specimen should be obtained by straight catheterization to avoid contamination by a nonurinary source of blood. Red urine without red blood cells (RBCs) suggests myoglobinuria or hemoglobinuria, porphyria Overview of Porphyrias Porphyrias are rare disorders in which there are defects in the pathway of heme synthesis due to genetic or acquired deficiencies of enzymes of the heme biosynthetic pathway. These deficiencies... read more , or ingestion of certain drugs or foods. Generally, the presence of hematuria should be confirmed by testing a 2nd specimen.
Presence of casts, protein, or dysmorphic RBCs (unusually shaped, with spicules, folding, and blebs) indicates a glomerular disorder Overview of Glomerular Disorders The hallmark of glomerular disorders is proteinuria, which is often in the nephrotic range (≥ 3 g/day). Glomerular disorders are classified based on urine changes as those that manifest predominantly... read more . White blood cells or bacteria suggest an infectious etiology. However, because urinalysis shows predominantly RBCs in some patients with cystitis Cystitis Bacterial urinary tract infections (UTIs) can involve the urethra, prostate, bladder, or kidneys. Symptoms may be absent or include urinary frequency, urgency, dysuria, lower abdominal pain... read more , urine culture is usually done. A positive culture result warrants treatment with antibiotics. If hematuria resolves after treatment and no other symptoms are present, no further evaluation is required for patients < 50, especially women.
If patients < 35 (including children) have only microscopic hematuria and no urine findings suggesting a glomerular disorder, no clinical manifestations suggesting a cause, no risk factors for cancer, and an identified benign cause (eg, infection, mild trauma), they can be observed, with urinalysis repeated every 6 to 12 months. If a benign cause is not evident or hematuria is persistent, testing is indicated (1 General reference Hematuria is red blood cells (RBCs) in urine, specifically > 3 RBCs per high-power field on urine sediment examination. Urine may be red, bloody, or cola-colored (gross hematuria with oxidation... read more ), beginning with ultrasonography or CT with contrast, sometimes followed by cystoscopy.
Patients < 50 with gross hematuria or unexplained systemic symptoms require ultrasonography or CT of the abdomen and pelvis.
If urine or clinical findings suggest a glomerular disorder, renal function is evaluated by measuring blood urea nitrogen, serum creatinine, and electrolytes; doing a urinalysis; and periodically determining the urine protein/creatinine ratio. Further evaluation of a glomerular disorder may require serologic tests, kidney biopsy Renal biopsy Biopsy of the urinary tract requires a trained specialist (nephrologist, urologist, or interventional radiologist). Indications for diagnostic biopsy include unexplained nephritic or nephrotic... read more , or both.
All patients ≥ 35 require cystoscopy Cystoscopy Cystoscopy is insertion of a rigid or flexible fiberoptic instrument into the bladder. Indications include the following: Helping diagnose urologic disorders (eg, bladder tumors, calculi in... read more , as do patients who are < 35 but have risk factors, such as a family history of cancer, or systemic symptoms (1 General reference Hematuria is red blood cells (RBCs) in urine, specifically > 3 RBCs per high-power field on urine sediment examination. Urine may be red, bloody, or cola-colored (gross hematuria with oxidation... read more ). Men ≥ 50 require discussion of testing for prostate-specific antigen Prostate-specific antigen (PSA) levels Benign prostatic hyperplasia (BPH) is nonmalignant adenomatous overgrowth of the periurethral prostate gland. Symptoms are those of bladder outlet obstruction—weak stream, hesitancy, urinary... read more through shared decision-making; those with elevated levels require further evaluation for prostate cancer.
General reference
1. Barocas DA, Boorjian ST, Alvarez RD, et al: Microhematuria: AUA/SUFU guideline. J Urol 204(4):778-786, 2020. doi: 10.1097/JU.0000000000001297
Treatment of Isolated Hematuria
Treatment is directed at the cause.
Key Points
Red urine should be differentiated from true hematuria (red blood cells in urine).
Urinalysis and urine sediment examination help differentiate glomerular from nonglomerular causes.
Risk of serious disease increases with aging and with duration and degree of hematuria.
Cystoscopy and imaging tests are usually needed for patients > 35 or for younger patients with systemic symptoms or risk factors for cancer.
Drugs Mentioned In This Article
Drug Name | Select Trade |
---|---|
phenazopyridine |
AZO Urinary Pain Relief Maximum Strength, Azo-100, Azo-Gesic, Azo-Septic, Azo-Standard, Phenazo, Prodium, Pyridium, Urinary Analgesic , Uristat, Uristat Relief, Uristat Ultra |
methyldopa |
Aldomet |
senna |
Black Draught , Ex-Lax, Fletchers Laxative, Geri-kot, Lax-Pills, Little Remedies for Tummys, Perdiem, Plus PHARMA, Senexon, Senna, SennaGen , Senna-Lax , Senna-Tabs, Senna-Time, Sennatural, Senokot, Senokot Extra Strength , Senokot Xtra, SenoSol, SenoSol-X, Uni-Cenna |
cyclophosphamide |
Cyclophosphamide, Cytoxan, Neosar |