Hematuria Flashcards
What is the definition of microscopic hematuria?
≥3 RBCs per high-power field (HPF) on urine microscopy.
What is the definition of gross hematuria?
Visible red or tea-colored urine due to the presence of RBCs.
What is pseudohematuria?
Red urine due to non-RBC pigments such as beets, rifampin, myoglobin, or bilirubin.
What is the first step in evaluating hematuria?
In the absence of trauma or suspected nephrolithiasis, the first step in evaluating hematuria is obtaining a urinalysis (UA) and urine. An urine dipstick will detect blood.
What is the next step if the urine dipstick is positive for blood?
Microscopic examination of urine sediment to confirm RBCs and rule out hemoglobinuria or myoglobinuria. A UA confirms the presence of hematuria and can differentiate between infectious, glomerular, and extraglomerular causes.
How do you differentiate hematuria from hemoglobinuria or myoglobinuria?
Microscopy: Hematuria shows RBCs, while hemoglobinuria and myoglobinuria do not show RBCs but still test positive on dipstick.
What could be the underlying etiology for gross hematuria?
Gross hematuria (ie, macroscopic or visible) may be due to renal (eg, glomerulonephritis, infection), ureteral (eg, nephrolithiasis), bladder (eg, cystitis, malignancy), or urethral (eg, urethritis, prostatitis) etiologies.
What conditions are associated with hematuria throughout urination?
Glomerulonephritis, pyelonephritis, nephrolithiasis, and upper urinary tract cancers.
What conditions are associated with terminal hematuria (blood at the end of urination)?
Cystitis, bladder stones or cancer, benign prostatic hyperplasia (BPH), and prostate cancer.
What conditions are associated with initial hematuria (blood at the beginning of urination)?
Urethral injury (trauma), urethritis.
How does glomerular hematuria present on urine microscopy?
Dysmorphic RBCs, RBC casts, and proteinuria. Patients with UA findings suggestive of glomerular etiologies for hematuria (eg, proteinuria, red cell casts, dysmorphic red cells) require evaluation for renal causes, including possible renal ultrasound, 24-hour urine studies, serological studies, and eventual renal biopsy.
What are common causes of glomerular hematuria?
- Glomerulonephritis (IgA nephropathy, post-streptococcal GN, lupus nephritis)
- Goodpasture disease
- Alport syndrome.
How does nephrolithiasis present clinically?
Flank pain radiating to the groin, gross or microscopic hematuria, nausea, vomiting, no fever.
What can cause hematuria in athletes?
The differential dark cola colored urine following exercise includes exercise-induced hematuria, myoglobinuria from rhabdomyolysis, and march hemoglobinuria from RBC trauma. All of these entities may result in a positive result for blood on urinalysis, although identifying intact RBCs on microscopy excludes myoglobinuria and hemoglobinuria. What helps to distinguish pathologic hematuria with benign causes is the absence of red blood cell casts, which makes a glomerular cause of his hematuria less likely. Exercise-induced hematuria is likely diagnosis in a patient who is an athlete. Up to 24% of participants in marathons may have exercise induced hematuria. This hematuria may be caused by repetitive up and down movements of the bladder during running. In contact sports, direct trauma to the kidneys or bladder may result in hematuria. Shunting of blood flow towards the muscles and away from the kidneys may also contribute. Even when an appropriate history is present, exercise hematuria should be considered a diagnosis of exclusion and repeat urinalysis should be done in one week to ensure resolution. Further evaluation would then be necessary if hematuria were still present, particularly in patients over the age of 50.
What is the most common cause of painless gross hematuria in an older adult?
Bladder cancer.
What is the most common cause of microscopic hematuria in young adults and children?
IgA nephropathy.
What medications can cause hematuria?
Anticoagulants (e.g., warfarin), cyclophosphamide (hemorrhagic cystitis).
What are the risk factors for urinary tract malignancies presenting with hematuria?
Age >40 in males, age >50 in females, smoking, chronic UTIs, exposure to chemicals (e.g., aniline dyes, cyclophosphamide).
What is the next step if hematuria is confirmed on microscopy?
Determine whether symptoms suggest infection, nephrolithiasis, or glomerular disease.
What imaging is used for nephrolithiasis evaluation?
Non-contrast CT abdomen/pelvis or ultrasound (if radiation is contraindicated).
What is the next step in gross hematuria with clots?
Urgent urology referral and CT abdomen/pelvis with contrast.
When should nephrology be consulted for hematuria?
If urine microscopy shows RBC casts, dysmorphic RBCs, or proteinuria.
When should urology be consulted for hematuria?
If there are risk factors for malignancy, unexplained hematuria, or urinary tract structural abnormalities. Patients with UA findings suggestive of glomerular etiologies for hematuria (eg, proteinuria, red cell casts, dysmorphic red cells) require evaluation for renal causes, including possible renal ultrasound, 24-hour urine studies, serological studies, and eventual renal biopsy.
What is the best imaging for evaluating unexplained hematuria in a high-risk patient?
CT urography (CT abdomen/pelvis with and without contrast).
What is the best imaging for evaluating bladder masses or bleeding?
Cystoscopy.
What imaging is preferred for stones or masses when radiation is contraindicated?
Renal ultrasound.
What condition presents with painless gross hematuria and is commonly seen in older males with a smoking history?
Bladder cancer.
What condition presents with recurrent gross hematuria after an upper respiratory infection?
IgA nephropathy.
What is the preferred diagnostic test for suspected prostate cancer in a patient with hematuria?
PSA testing and prostate biopsy if indicated.
What condition presents with hematuria and is associated with sickle cell disease?
Renal papillary necrosis.
What is the significance of persistent hematuria with negative urine culture and normal imaging?
Further evaluation with cystoscopy is needed to rule out bladder pathology.
How does hematuria due to exercise resolve?
Usually self-limited and resolves with rest.
What is the most concerning potential diagnosis for painless hematuria in an elderly smoker?
Bladder cancer (urothelial carcinoma).
When should a patient with hematuria undergo a 24-hour urine collection?
If recurrent hematuria with normal imaging, to evaluate for metabolic disorders (e.g., hypercalciuria, hyperuricosuria).
What is the recommended follow-up for persistent microscopic hematuria without an identified cause?
Annual urinalysis for at least 3 years to monitor for progression.
