Asymptomatic microhematuria

Question 1

Def asymptomatic micro hematuria

Answer 1

Asymptomatic microhematuria (AMH) is defined as 3 or greater red blood cells (RBC) per high powered field (HPF) on a properly collected urinary specimen in the absence of an obvious benign cause. A positive dipstick does not define AMH and evaluation should be based solely on findings from microscopic examination of urinary sediment and not on a dipstick reading. A positive dipstick reading merits microscopic examination to confirm or refute the diagnosis of AMH.

Question 2

Guideline statements

Answer 2

The assessment of the asymptomatic microhematuria patient should include a careful history, physical examination, and laboratory examination to rule out benign causes of AMH, such as infection, menstruation, vigorous exercise, medical renal disease, viral illness, trauma, or recent urological procedures.

• Once benign causes have been ruled out, the presence of asymptomatic microhematuria should prompt a urologic evaluation.
• At the initial evaluation, an estimate of renal function should be obtained (may include calculated eGRF, creatinine, and blood urea nitrogen [BUN]) because intrinsic renal disease may have implications for renal related risk during the evaluation and management of patients with AMH.
• The presence of dysmorphic red blood cells, proteinuria, cellular casts, and/or renal insufficiency or any other clinical indicator suspicious for renal parenchymal disease warrants concurrent nephrologic workup but does not preclude the need for urologic evaluation.
• Microhematuria that occurs in patients who are taking anticoagulants requires urologic evaluation and nephrologic evaluation regardless of the type or level of anti-coagulation therapy.
• For the urologic evaluation of asymptomatic microhematuria, a cystoscopy should be performed on all patients aged 35 years and older.
• In patients younger than age 35 years, cystoscopy may be performed at the physician’s discretion.
• A cystoscopy should be performed on all patients who present with risk factors for urinary tract malignancies (e.g., irritative voiding symptoms, current or past tobacco use, chemical exposures) regardless of age.
• The initial evaluation for AMH should include a radiologic evaluation. Multi-phasic computed tomography (CT) urography (without/with IV contrast), including sufficient phases to evaluate the renal parenchyma to rule out a renal mass and an excretory phase to evaluate the urothelium of the upper tracts, is the imaging procedure of choice because it has the highest sensitivity and specificity for imaging the upper tracts.
• For patients with relative or absolute contraindications that preclude use of multiphasic CT (such as renal insufficiency, contrast allergy, pregnancy), magnetic resonance urography (MRU) (without/with intravenous contrast) is an acceptable alternative imaging approach.
• For patients with relative or absolute contraindications that preclude use of multiphasic CT (such as renal insufficiency, contrast allergy, pregnancy) where collecting system detail is deemed imperative, combining MRI with retrograde pyelograms (RPGs) provides alternative evaluation of the entire upper tracts.
• For patients with relative or absolute contraindications that preclude use of multiphasic CT (such as renal insufficiency, contrast allergy) and MRI (presence of metal in the body) where collecting system detail is deemed imperative, combining non-contrast CT or renal ultrasound (US) with retrograde pyelograms (RPGs) provides alternative evaluation of the entire upper tracts.
• The use of urine cytology and urine markers (NMP22, BTA-stat, and UroVysion FISH) is NOT recommended as a part of the routine evaluation of the asymptomatic microhematuria patient.
• In patients with persistent microhematuria following a negative work up or those with other risk factors for carcinoma in situ (e.g., irritative voiding symptoms, current or past tobacco use, chemical exposures), cytology may be useful.

Question 3

Asymptomatic microhematuria - f/u

Answer 3

• Blue light cystoscopy should not be used in the evaluation of patients with asymptomatic microhematuria.
• If a patient with a history of persistent asymptomatic microhematuria has two consecutive negative annual urinalyses (UA) [one per year for 2 years from the time of initial evaluation or beyond], then no further UA for the purpose of evaluation of AMH is necessary.
• For persistent asymptomatic microhematuria after negative urologic work up, yearly UA should be conducted.
• For persistent or recurrent asymptomatic microhematuria after initial negative urologic work-up, repeat evaluation within 3-5 years should be considered.

Question 4

Common risk factors for UCC in pts with microhematuria

Answer 4