Hematuria

Postrenal hematuria - the presence of blood in urine (because of damage to the urethra and prostate).

Glomerular causes include:

• IgA nephropathy[4]
• Thin glomerular basement membrane disease[4]
• Hereditary nephritis (Alport's disease)[6]
• Hemolytic uremic syndrome[6]
• Postinfectious glomerulonephritis[4]
  • Certain infectious agents like Group B Strep(strep pyogenes) can cause a person to get a very specific manifestation known as post-streptococcal glomerulonephritis. This manifestation results in a person having the symptom of cola-colored urine.
• Membranoproliferative glomerulonephritis[4]
• Lupus nephritis[4]
• Henoch-Shonlein purpura[6]
• Nephritic syndrome[7]
• Nephrotic syndrome[4]
• Polycystic kidney disease[4]
• Idiopathic hematuria[8]

Visible blood clots in the urine indicate a non-glomerular cause.[6] Non-glomerular causes include:

• Urinary tract infections, such as pyelonephritis, cystitis, prostatitis, and urethritis[4][6]
• Kidney stones[4]
• Cancers, such as renal cell carcinoma and bladder cancer (particularly transitional cell carcinoma), and in men, prostate cancer[4]
• Urinary tract strictures[6]
• Benign prostatic hyperplasia[6]
• Renal papillary necrosis[6]
• Trauma or damage to the lining of the urinary tract[4]
• Intense exercise[4]
• Increased tendency to bleed due to acquired or genetic conditions (e.g. sickle cell disease or vitamin K deficiency bleeding) or certain medications (e.g. blood thinners)[4][6]

Not all red or brown urine is caused by hematuria.[3] Other substances such as certain medications and certain foods can cause urine to appear red.[3]

Medications that may cause urine to appear red include:

• Phenazopyridine[6]
• Nitrofurantoin[6]
• Doxorubicin[6]
• Rifampicin[6]

Foods that may cause urine to appear red include:

• Blackberries[6]
• Food dyes.[6]
• Beets[3]
• Rhubarb[3]
• Fava beans[9]

A urine dipstick may be falsely positive for hematuria due to other substances in the urine.[6] While the urine dipstick test is able to recognize heme in red blood cells, it also identifies free hemoglobin and myoglobin.[6] Free hemoglobin may be found in the urine resulting from hemolysis, and myoglobin may be found in the urine resulting from rhabdomyolysis.[6][5] Thus, a positive dipstick test does not necessarily indicate hematuria; rather, microscopy of the urine showing three of more red blood cells per high power field confirms hematuria.[6][3]

In women, menstruation may cause the appearance of hematuria and may result in a urine dipstick test positive for hematuria.[3] Menstruation can be ruled out as a cause of hematuria by inquiring about menstruation history and ensuring the urine specimen is collected without menstrual blood.[3]

The first step in evaluation of red or brown colored urine is to confirm true hematuria with urinalysis and urine microscopy, where hematuria is defined by three of more red blood cells per high power field.[3] Although a urine dipstick test may be used, it can give false positive or false negative results.[4] In gathering information, it is important to inquire about recent trauma, urologic procedures, menses, and culture-documented urinary tract infection.[3] If any of these are present, it is appropriate to repeat a urinalysis with urine microscopy in 1 to 2 weeks or after treatment of the infection.[6][3] If the results of the urinalysis and urine microscopy reveal a glomerular origin of hematuria (indicated by proteinuria or red blood cell casts), consultation of a nephrologist should be made.[6] If the results of the urinalysis indicate a non-glomerular origin, a microbiological culture of the urine should be performed, if it has not been done already.[6] If the culture is positive, treatment of the infection should follow and urinalysis and urine microscopy should be repeated once complete.[6] If the culture is negative or if hematuria persists after treatment, CT urogram and cystoscopy should be performed.[6] Of note, hemodynamic stability should be monitored and a complete blood count should be ordered to assess for anemia.[3]

In summary, those with visible hematuria confirmed by urinalysis and urine microscopy and with no recent trauma, urologic procedures, menses, or urinary tract infection should undergo cystoscopy and CT urogram.[3]

Red blood cells seen on light microscopy on urinary cytology, next to benign urothelial cells (Pap stain).

After detecting and confirming hematuria with urinalysis and urine microscopy, the first step in evaluation of microscopic hematuria is to rule out benign causes.[12] Benign causes include urinary tract infection, viral illness, kidney stone, recent intense exercise, menses, recent trauma, or recent urological procedure.[12] After benign causes have resolved or been treated, a repeat urinalysis and urine microscopy is warranted to ensure cessation of hematuria.[12] If hematuria persists (even if there is a suspected cause), the next step is to stratify the risk of the person for urothelial cancer into low, intermediate, or high risk to determine next steps.[13] To be in the low risk category, one must satisfy all of the following criteria: Has never smoked tobacco or smoked less than 10 pack-years; is a female less than 50 years old or a male less than 40 years old; has 3-10 red blood cells per high power field; has not had microscopic hematuria before; and has no other risk factors for urothelial cancer.[13] To be in the intermediate risk category, one must satisfy any of the following criteria: Has smoked 10-30 pack-years; is a female 50–59 years old or a male aged 40–59 years old; has 11-25 red blood cells per high power field; or was previously a low-risk patient with persistent microscopic hematuria and has 3-25 red blood cells per high power field.[13] To be in the high risk category, one must satisfy any of the following criteria: Has smoked more than 30 pack-years; is older than 60 years of age; or has above 25 red blood cells per high power field on any urinalysis.[13] For the low risk category, the next step is to either repeat a urinalysis with urine microscopy in 6 months or perform a cystoscopy and renal ultrasound.[13] For the intermediate risk category, the next step is to perform a cystoscopy and renal ultrasound.[13] For the high risk category, the next step is to perform a cystoscopy and CT urogram.[13] If an underlying cause for hematuria is discovered, it should be managed appropriately.[13] However, if no underlying cause is discovered, the hematuria should be re-evaluated with urinalysis and urine microscopy within 12 months.[13] Additionally, for all risk categories, if a nephrologic origin is suspected, consultation of a nephrologist should be made.[13]

A 60cc/mL Toomey syringe. 1) Fill syringe with saline. 2) Connect syringe to a catheter port 3) Instill 180cc of saline 4) Draw back 180cc of bladder urine 5) Dispose of medical waste 6) Repeat until all clots are removed

Acute clot retention is one of three emergencies that can occur with hematuria.[14] The other two are anemia and shock.[14] Blood clots can prevent urine outflow through either ureter or the bladder.[14] This is known as acute urinary retention.

Blood clots that remain in the bladder are digested by urinary urokinase producing fibrin fragments.[14] These fibrin fragments are natural anticoagulants and promote ongoing bleeding from the urinary tract.[14] Removing all blood clots prevents the formation of this natural anticoagulant.[14] This in turns facilitates the cessation of bleeding from the urinary tract.[14]

The acute management of obstructing clots is the placement of a large (22-24 French) urethral Foley catheter.[14] Clots are evacuated with a Toomey syringe and saline irrigation.[14] If this does not control the bleeding, management should escalate to continuous bladder irrigation (CBI) via a three-port urethral catheter.[14] If both a large urethral Foley catheter and CBI fail, an urgent cystoscopy in the operating room will be necessary.[14] Lastly, a transfusion and/or a correction of a coexisting coagulopathy may be necessary.[14]

Urosepsis is defined as sepsis caused by a urogenital tract infection and comprises about 25% of all sepsis cases.[15] Urosepsis is the result of a systemic inflammatory response to infection and can be identified by numerous signs and symptoms (e.g. fever, hypothermia, tachycardia, and leukocytosis).[15] Signs and symptoms that indicate a urogential tract infection is the source of the sepsis may include, but are not limited to, flank pain, costovertebral angle tenderness, pain with micturition, urinary retention, and scrotal pain.[15] In terms of the visibility, hematuria can be visible to the naked eye (termed "gross hematuria") and may appear red or brown (sometimes referred to as tea-colored), or it can be microscopic (i.e. not visible to the eye but detected of urosepsis.[15] In addition to imaging tests, patients may be treated with antibiotics to relieve the infection and intravenous fluids to maintain cardiovascular and renal perfusion.[15] Acute management of hemodynamic status, in the event intravenous fluids are unsuccessful, may include the use of vasopressor medications and the placement of a central venous line.[15]