Hematuria

Background

• Definition: 3 urinalyses with three or more RBC/hpf; 1 urinalysis with 100 RBC/hpf or gross hematuria (1 cc blood/L urine can induce color change)
• Can be transient (exercise-induced, menses, trauma)
• Hemoglobinuria: Hgb should be found only in intact RBCs, presence in urine suggests intravascular hemolysis AND fully saturated haptoglobin sites in serum
• Myoglobinuria: should be found only in intact muscle, presence in urine suggests myonecrosis (serum haptoglobin has LOW affinity for myoglobin)
• Concurrent pyuria/dysuria: consider urinary tract infection or bladder malignancy
• Recent URI: think infection related glomerulonephritis, IgA, vasculitis, anti-GBM
• Positive Family Hx of Hematuria: consider PKD, Sickle Cell Disease
• Bleeding from other sites: think inherited/acquired bleeding disorder, anticoagulation
• Unilateral Flank Pain: Ureteral calculus, renal malignancy, IgA Nephropathy
• Microscopic hematuria – should be considered for CT Urography and cystoscopy
• Malignancy Risk Factors: male sex, age > 35, smoking Hx, exposures to benzene/aromatic amine, cyclophosphamide, indwelling foreign body, pelvis irradiation, chronic UTIs, h/o heavy NSAID use, h/o urologic disorders/disease (nephrolithiasis, BPH)

Evaluation

• Step 1: Confirm the presence of hematuria 
  • Dipstick positive heme: urinary RBCs (hematuria), free myoglobin or free hemoglobin
  • Centrifuge the urine 
    • • Red sediment -> true hematuria (urinary RBCs)
      • Red supernatant +

• • Positive dipstick: myoglobulin or hemoglobin
  • Negative dipstick porphyria, Pyridium, beets, rhubarb, or ingestion of food dyes
• Step 2: Determine if there is a GLOMERULAR or NON-GLOMERULAR source of bleeding

• • Glomerular Bleeding:
    • • Isolated Hematuria: Differential includes IgA Nephropathy, thin BM dx, Alport’s
      • Nephritic syndrome (new proteinuria, pyuria, HTN, edema, rise in Cr): post-infectious GN, MPGN, ANCA vasculitis, Goodpasture’s, lupus nephritis
      • Workup: anti-GMB, anti-DNase/ASO, ANA, ANCA, C3, C4, cryo, Hep B & C, HIV
      • Indications for Renal Biopsy: glomerular bleeding + risk factors for progressive disease, including albuminuria > 30 mg/day, new hypertension > 140/90 or significant elevation over baseline BP, rise in serum creatinine
  • Extraglomerular Bleeding (Imaging Section)
    • • If historical clues suggest nephrolithiasis, start with non-con CT A/P
      • Gross Hematuria otherwise should be evaluated with CT A/P w/ and w/o contrast (CT urography); consult urology for cystoscopy (often done as outpatient referral)
      • If clots are passed, more likely to be secondary to lower urinary source, and if a high burden of clots poses a risk of obstruction (urologic emergency)
      • If extraglomerular bleeding with clots: hematuria catheter needs to be placed ASAP (2 valve catheter, 20-24 Fr (!); page urology if nursing unable to obtain)
  • CT Urography is more sensitive than IV pyelogram for renal masses and stones.
  • Prefer Renal and Bladder Ultrasound in pregnant patients
  • All pts w/gross hematuria that is non-glomerular in source, in whom infection has been ruled out, warrant cystoscopy. Additionally, all patients with clots need cystoscopy