What is the appropriate management for a 3-month-old infant with transient microscopic hematuria (presence of tiny red flecks of blood in 2 diapers) who is otherwise well and happy?

Management of Transient Microscopic Hematuria in a 3-Month-Old Infant

For a 3-month-old infant with tiny red flecks of blood in 2 diapers that has already resolved and who is otherwise well and happy, no imaging or further workup is indicated at this time. 1

Rationale for Conservative Management

The American College of Radiology explicitly states that patients without proteinuria or dysmorphic red blood cells are unlikely to have clinically significant renal disease, and no imaging is indicated. 1 This recommendation is particularly relevant for your case given:

• The hematuria was transient (only 2 diapers) and has already resolved 1
• The infant is otherwise completely well and asymptomatic 1
• There are no concerning associated symptoms (no fever, vomiting, poor feeding, or signs of systemic illness) 1

In a large study of 325 pediatric patients with microscopic hematuria where 87% underwent renal ultrasound and 24% had voiding cystourethrography, no findings were deemed clinically significant. 1

What to Monitor For

If hematuria recurs or persists, confirm it is true hematuria by:

• Obtaining urinalysis with microscopic examination to document ≥5 red blood cells per high-powered field 1
• Checking for proteinuria, which would indicate glomerular disease requiring nephrology referral 1, 2
• Looking for dysmorphic red blood cells or red cell casts, which suggest glomerular pathology 1, 2

When Further Evaluation Would Be Needed

Imaging (renal and bladder ultrasound) would only be appropriate if: 1

• Hematuria becomes persistent (defined as present in 2 or 3 of 3 consecutive properly collected specimens) 1
• The infant develops macroscopic/gross hematuria (visible blood) 1
• Associated symptoms develop such as proteinuria, hypertension, edema, or decreased urine output 1
• The infant becomes symptomatic or unwell 1

Important Caveats

Do not order CT, MRI, VCUG, or other advanced imaging for isolated, transient microscopic hematuria in an otherwise well infant—these are not appropriate and expose the child to unnecessary risk. 1 The ACR guidelines are explicit that these modalities are not indicated for isolated nonpainful, nontraumatic microscopic hematuria without proteinuria. 1

Isolated microscopic hematuria is very rarely the presenting scenario of Wilms tumor, so the brief, self-limited nature of this finding should not trigger oncologic concerns. 1

Recommended Approach

Reassure the parents and provide anticipatory guidance: 1

• Explain that brief, isolated microscopic hematuria in infants is common and usually benign 1
• Instruct parents to monitor for recurrence of blood in diapers 1
• Advise them to return if hematuria recurs, persists, or if the infant develops any concerning symptoms 1
• No follow-up testing is needed unless hematuria recurs 1

Screen for benign causes if hematuria recurs: 2

• Recent vigorous activity or minor trauma 2
• Urinary tract infection (though this would typically present with other symptoms in an infant) 2
• Recent illness or fever 2