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Evaluation of Microscopic Hematuria. Alon Z. Weizer, MD, MS Division of Urologic Oncology Department of Urology University of Michigan. Microscopic Hematuria (MH). Objectives of Presentation Appreciate the importance & possible etiologies of MH
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Evaluation of Microscopic Hematuria Alon Z. Weizer, MD, MS Division of Urologic Oncology Department of Urology University of Michigan
Microscopic Hematuria (MH) • Objectives of Presentation • Appreciate the importance & possible etiologies of MH • Understand the proper determination of MH • Consider the steps in evaluation of MH • Articulate recommended follow-up in cases of MH with negative initial evaluation
Why Evaluate MH? • Gross hematuria is very often an indication of disease • Although less ominous, MH also can be an indication of disease • While many of these abnormalities are minor, some are significant and/or life-threatening
Possible Causes • Life-Threatening • Cancer • Renal parenchyma • Renal pelvic • Ureteral • Bladder • Prostatic • Urethral • Penile • AAA • Require Treatment • Calculi • Vesico-ureteralreflux • Infection • Ureteralobstruction • Symptomatic urethral obstruction • Renal parenchymaldisease • Symptomatic BPH • Renal artery stenosis • Renal vein thrombosis
Prevalence of MH • 0.2% to 16% in population studies • 2.5% to 21% in screening programs • 13% to 21% in men >60 years old • Likelihood of finding etiology of MH varies with risk • Low risk: Significant finding <5% • High risk: Significant finding >50%
Updated Clinical Guidelines • AUA Best Practices Panel: • Urology, Nephrology, Family Medicine, Radiology • Literature review & expert opinion • Critique of document by other physicians • Approval of AUA
Purpose of Recommendations • Resource for urologists & PCPs • Directed towards evaluation of asymptomatic MH in adults • Not meant to address: • Screening for hematuria • Gross hematuria • Symptomatic hematuria • Pediatric age group
Determination of MH • Freshly voided, clean-catch, midstream specimen • Dipstick for Hb is screening test only • 95% sensitive, but only ~80% specific • In population with 10% hematuria, PPV of Dipstick is only 35% • Positive Dipstick must be confirmed by microscopy (>3 RBC/hpf)
Determination of MH • >3 RBC/hpf is standard criterion • 1 to 2 RBC/hpfdoesn’t require evaluation in most • However, it might if risk factors present • Just 1 specimen with hematuriashould prompt evaluation • Old rule: 2 of 3 properly collected specimens was standard criterion
Why the Change? • There is substantial evidence that MH caused by a serious underlying condition can be highly intermittent • Studies that evaluated patients after 1 positive sample, rates of malignancy in most were over 2% • Non-life-threatening diagnoses that would benefit from active management or follow-up are frequently found
Risk Factors for Significant Disease • Smoking history • Occupational exposure to chemicals or dyes • Benzenes or aromatic amines • History of analgesic abuse • Age >40 years • Significant urological history • Previous gross hematuria • Irritative voiding symptoms • Urinary tract infection • Prior pelvic radiation
Determination of MH • Hematuria cannot be determined in presence of squamous epithelial cells • These cells may indicate contamination from source outside urinary tract • Frequent in women • Difficultly obtaining perfect clean-catch specimen • Occasionally in men • Phimosis (cells from foreskin) • Squamous cells may be present in bladder urine
Determination of MH • If there appears to be hematuria, but squamous cells are present, then get catheterized specimen • Most common reason for “unnecessary” hematuria referral = contaminated specimen • Conversely, urine w/o RBCs is adequate for determination, even if there are squamous cells
Glomerular Hematuria • Origin of blood from renal parenchymal disease can be suggested by UA • Dysmorphic RBCs (variable size & shape w/irregular outline) → sensitive • Plain microscopy, or may need inverted phase-contrast microscopy
Asymptomatic MH History and Physical Examination Rule Out Benign Causes: Menstruation Vigorous Exercise Sexual Activity Viral Illness Trauma Infection Resolved after Tx or delay Persistent No Evaluation Evaluation Required
Evaluation: H&P • Gross or microscopic? • Gross more often assoc w/significant disease • Initial, terminal or total? • Initial = urethra, terminal = bladder neck/prostate • Pain, dysuria, bladder irritability • Suspect infection or obstruction • Anti-coagulated • Still require evaluation
Evaluation: H&P • Sickle cell, diabetes • Family or personal history of calculi, PCKD, other GU/Neph diseases • Trauma, physical or sexual activity • Tobacco use, occupational exposure • Association with menses • Fever, palpable mass, atrial fibrillation, visible blood at meatus, CVAT
Confirmed MH (obtain Serum Cr) Suggestion of Primary Renal Disease? Proteinuria* (> 500 to 1000 mg / day) Dysmorphic RBCs or RBC casts Elevated Serum Cr Yes No Urology Referral + Concurrent Nephrology Evaluation Urological Evaluation * Dipstick >1+ for protein prompts 24 hr urine
Purpose of Urological Eval • Upper tract imaging • Diseases of the kidney & ureter • Most commonly &/or significantly: • Calculi • Urothelial lesions • Obstruction • Renal masses • Cystoscopy • Diseases of the bladder & urethra • Most commonly &/or significantly: • Bladder cancer • BPH • Urethral strictures
Urological Evaluation for Asymptomatic MH Upper Tract Imaging Multi-phasic CT urography Alternative1 : MR urography Alternative 2: RPGs w/MRI Cystoscopy In patients ≥35 years & Patients w/RFs regardless of age (Discretionary: those <35 w/o RFs) Abnormal? Abnormal? Yes Yes Treat No No Consider Urine Cytology Follow-up Protocol
Imaging Modalities • Computed Tomography • Best modality for characterization of small renal masses • More widely available & less expensive than MRI • Best modality for calculi, renal and perirenal infection & associated complications • Sensitivity for urothelial lesions not defined with certainty, but thought to be good with “urography” technique
CT Urogram
Other Options • MR urography • Pregnancy, patients with iodinated contrast allergy • Risk of nephrogenic systemic fibrosis in patients with renal insufficiency • Retrograde pyelograms combined w/magnetic resonance imaging
Follow-Up Protocol • UA at 12 & 24 months • If negative for 2 consecutive years, then D/C • If persistent asympomatic MH, repeat urological evaluation w/in 3 – 5 years • If gross hematuria or new voiding sx, repeat urological evaluation
Before Urological Referral • Determine if this is real MH • >3 RBC/hpf • Catheterized urine if squamous cells • Exclude benign causes w/H&P • Likely glomerular → Refer to neph, too • Obtain serum Cr • Order imaging