Approach to hematuria
Hematuria is present in urine when at least 3 erythrocytes per high-power field are seen on microscopy, and the first branch point is glomerular versus nonglomerular bleeding, based on erythrocyte morphology and casts. Gross hematuria always requires urologic evaluation and cystoscopy, asymptomatic microscopic hematuria is risk-stratified by American Urological Association criteria to select repeat testing, imaging, or cystoscopy, and glomerular hematuria is treated with disease-specific immunosuppression after biopsy.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Hematuria is defined by a laboratory threshold, not visibility: the presence of at least 3 erythrocytes per high-power field (hpf) on urine sediment microscopy, whether or not it is visible to the naked eye.
- Epidemiology
Nonglomerular causes predominate overall: hematuria is most often nonglomerular in origin, arising from the urinary tract rather than the glomerulus.
- Risk factors
Age older than 60 years: an AUA high-risk criterion for underlying urothelial malignancy.
- Pathophysiology
Nonglomerular (isomorphic) hematuria reflects direct bleeding into the urinary tract: round erythrocytes of consistent size, unaltered by passage through a damaged filtration barrier, result from…
- Clinical features
Erythrocyte morphology on urine microscopy establishes the origin: isomorphic (round, uniform) erythrocytes suggest a nonglomerular source; dysmorphic erythrocytes, especially acanthocytes, or…
- Differential diagnosis
Renal cell carcinoma: an AUA high-risk-category malignancy; distinguished by a renal mass on imaging rather than a diffuse mucosal or glomerular process.
- Diagnosis
The diagnosis of hematuria itself is a laboratory threshold, not a clinical criteria set: at least 3 erythrocytes/hpf on microscopic urinalysis confirms hematuria; the subsequent workup establishes…
- Management
First, treat the identified cause once the workup localizes it: trimethoprim 160 mg/sulfamethoxazole 800 mg PO twice daily for 3 days for uncomplicated cystitis (or a fluoroquinolone/broader regimen…
- Complications
Delayed diagnosis of urothelial or renal malignancy: the principal harm of under-evaluating gross or high-risk microscopic hematuria.
- Prognosis
Prognosis tracks the underlying cause, not the hematuria itself: low-risk AMH with a negative repeat urinalysis requires no further evaluation and carries an excellent prognosis, while high-risk…
- Prevention
Do not use urinalysis as a urothelial cancer screening test in asymptomatic adults, since it is not validated for that purpose; investigate only when hematuria is actually found.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Glomerular disorders: an overview of nephritic and nephrotic syndrome
Glomerular disease presents as one of two clinical syndromes, nephrotic (heavy proteinuria, hypoalbuminemia, edema) or nephritic (hematuria with dysmorphic erythrocytes or casts, often with hypertension and reduced kidney function), which frame the differential and guide the kidney biopsy workup. Recognizing which syndrome a patient has determines the urgency of evaluation and the initial management.
- Focal segmental glomerulosclerosis (FSGS)
Focal segmental glomerulosclerosis is a podocytopathy causing segmental glomerular scarring on biopsy, presenting with nephrotic-range proteinuria and accounting for up to 40% of primary nephrotic syndrome in adults. Diagnosis requires kidney biopsy, and primary disease is treated with high-dose glucocorticoids followed by calcineurin inhibitors for resistant cases.
- IgA nephropathy
IgA nephropathy is the most common primary glomerular disease worldwide, caused by galactose-deficient IgA1 immune complexes depositing in the mesangium, presenting classically with synpharyngitic gross hematuria in young adults and confirmed by kidney biopsy showing dominant mesangial IgA deposits. First-line therapy is renin-angiotensin system blockade, since roughly 40% of patients progress to end-stage kidney disease within 15 years despite treatment.
- Nephrolithiasis
Nephrolithiasis affects 7-11% of the US population, most often as calcium oxalate stones, and presents as colicky flank pain radiating to the groin with hematuria. Noncontrast CT confirms the diagnosis and stone size drives management: hydration, NSAID/opioid analgesia, and alpha-blocker expulsive therapy for stones under 10 mm, urologic intervention for larger, infected, or obstructing stones.
- Renal cell carcinoma
Renal cell carcinoma is the most common kidney cancer, arising from renal tubular epithelium (most often clear cell), and is now diagnosed incidentally on imaging in most patients rather than through the classic triad of flank pain, hematuria, and mass. Contrast CT or MRI showing an enhancing solid renal mass is usually sufficient to diagnose and stage disease, and treatment is surgical for localized tumors versus tyrosine kinase inhibitors and immune checkpoint inhibitors for metastatic, chemo- and radio-resistant disease.