Obtaining a urinalysis is often part of the management plan in the Ped ED to screen for a condition.  Often it is obtained to look for possible infection.  Sometimes we are evaluating unusual swelling with concern for proteinuria. What, however, do we need to consider when we encounter Microscopic Hematuria?

Hematuria

• Blood, obviously, should not be in the urine, but it is relatively commonly encountered. [Davis, 2015]
• Hematuria, strictly defined, is the presence of 5 or more RBCs per HPF. [Massengill, 2008]
  • Officially, this requires three successive samples obtained over several weeks…
  • So, keep this in mind as many times the most appropriate next step is to have the urinalysis repeated later by the Primary Physician.
    • The prevalence of asymptomatic microscopic hematuria decreases from ~6% to ~0.5% upon repeating the screening specimen. [Massengill, 2008]

• It can be further described as:
  • Persistent vs Transient
  • Symptomatic vs Asymptomatic
  • Gross vs Microscopic
    • Gross hematuria, unlike microscopic, is more likely to be associated with an identifiable cause.
    • Gross hematuria considerations = UTI, trauma, nephrolithiasis, coagulopathies, crystalluria, and renal disease.
    • Gross hematuria associated with edema/proteinuria and/or hypertension warrants concern for renal disease, like Post-Infectious Glomerulonephritis. [Davis, 2015]
    • Gross hematuria with abdominal pain and/or rash? Think HSP.

• It can also be described based on pathologic origin:
  • Glomerular vs ExtraGlomerular
    • Glomerular hematuria
      • RBCs inappropriately cross the glomerular capillary wall.
      • Due to inflammation, structural defects, or toxic effects on nephron.
      • U/A findings – RBC, WBC Casts, dysmorphic RBCs, 2+ or > Proteinuria
      • Urine Protein / Creatinine ratio > 0.2 is suggestive of glomerular source.
    • ExtraGlomerular
      • Bleeding source at any other location of the urinary tract.
      • No Casts, normal RBC morphology, <2+ Proteinuria

• Different from adults, hematuria in children is often not urologic issue and kids rarely need cystoscopy. [Massengill, 2008]

Hematuria: Mimics

• Before we get carried away with a large work-up for “blood in the urine,” consider…
• False positive results are common.

• Substances can alter urine dipstick results:
  • Myoglobin
    • Confirm + Heme result on dipstick with microscopy.
    • + Heme without RBCs? Think Rhabdomyolysis!
•  Several substances can alter the appearance of the urine, but there is no true blood present:
  • Drugs
    • ex, Nitrofurantoin, sulfonamides, and salicylate
  • Toxins
    • ex, Lead and benzene
  • Foods
    • ex, Beets, food coloring, blackberries, rhubarb, paprika
  • Urate crystals 
    • Often seen in neonates diapers

“HEMATURIA” History

• Important historic factors that should be considered when evaluating hematuria can be recalled with the mnemonic “HEMATURIA.” [Davis, 2015]
  • Headaches
  • Edema
  • Myalgias
  • Arthralgias
  • Time course
  • Urinary symptoms
  • Recent sore throat
  • Infection (ex, UTIs)
  • Abdominal pain

Hematuria: Microscopic

• Microscopic hematuria often generates the biggest questions.
• First ask, is this Symptomatic or Asymptomatic?

• Symptomatic Microscopic Hematuria
  • Naturally, requires the greatest attention. [Massengill, 2008]
  • Symptoms are often not specific – i.e., fever, malaise
  • Symptoms may point toward diagnosis – ex, abdominal pain, edema, oliguria

•  Asymptomatic Microscopic Hematuria
  • Rarely found to have significant renal disease and is often transient.
    • Extensive evaluation is not necessary. [Massengill, 2008]
    • Close follow-up, however, is necessary! [Davis, 2015]
  • Family history is particularly important to help risk stratify these patients.
    • Family history of hematuria or renal impairment?
    • Family history of hearing or ocular abnormalities?
  • Be mindful of concurrent proteinuria, even if asymptomatic!
    • Finding both does not diagnose a pathologic condition, but it is more concerning for a glomerular process. [Massengill, 2008]

Hematuria: Initial Evaluation

1. Obtain microscopy to confirm that it is hematuria.
2. Evaluate for infection.
3. Pay attention to RBC morphology and presence of casts or crystals.
4. Consider close follow-up and further evaluation as outpatient.
   • Repeating test 2 to 3 times over the course of 2 weeks is advocated prior to further testing.
5. If history or exam inspires you to evaluate further in the ED (ex, edema, hypertension, symptomatic) consider:
   • Bun/Cr
   • Hemoglobin and platelet counts
   • If concern for acute Post-Infectious Acute Glomerulonephritis, consider:
     • ASO titer
     • C3 level
6. Emergent imaging is usually not required for microscopic hematuria.

References

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