Proteinuria and Hematuria Lecture Notes

Jul 22, 2024

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Proteinuria and Hematuria

Proteinuria

  • Common Finding in routine urinalysis.
  • Indicators of Early Renal Disease: Even small amounts warrant evaluation.
  • Daily Protein Filtration: ~15 kg, but less than 150 mg is excreted.
  • Definition:
    • Greater than 150 mg/day.
    • Hallmark of renal disease.

Microalbuminuria

  • Very early sign.
  • 30-150 mg/day.
  • Common in patients with diabetes or hypertension.

Macroalbuminuria

  • Greater than 300 mg/day.
  • Can be transient or persistent.

Causes of Proteinuria

  • Glomerular capillary wall weakness: Allows albumin to filter through (most common type).
  • Proximal tubular cell malfunction: Cells no longer reabsorb protein.
  • Overwhelming of tubular cells: Low molecular weight proteins overwhelm the cells.
  • Occurs in: Prolonged exercise, serious illness (nephrotic syndrome, diabetic nephropathy), pregnancy.
    • Pregnancy Specific: Less than 24 weeks - glomerulonephritis; Greater than 24 weeks - preeclampsia.

History & Diagnostics

  • Thorough History: Acute/chronic illness, surgeries, diagnostic procedures (contrast dye), urinary symptoms, UTI, risk for HIV, medications (OTC, herbal), family history of diabetes/renal disease, physical activity.
  • Diagnostics:
    • Urine dipstick (>= 1+ on two occasions).
    • Various urine and blood tests (detailed in Butaro textbook).

Management

  • Depends on Cause:
    • Stop medications contributing to proteinuria.
    • ACE inhibitors or ARBs for renal protection.
    • Tight control of glucose, lipids, blood pressure.
    • Consider sodium/protein restricted diet for some patients.

Hematuria

  • Common Finding in routine urinalysis.
  • Definition: 3 or more blood cells on microscopic evaluation.
  • Types:
    • Transient: Present once.
    • Persistent: Present on two or more occasions.

Causes

  • Most Common: Bladder cancer.
  • Other Causes: Local renal disease, systemic disease, glomerular/interstitial nephritis (if combined with proteinuria).
  • Risk Factors:
    • Older males (highest prevalence).
    • Long distance runners (13% prevalence).
    • Recent illness, sore throat, or skin infection (post-infection glomerulonephritis).

History & Diagnostics

  • Thorough History:
    • Urinary patterns, color of urine, age, gender.
    • Physical activity.
    • Presence of pain (indicator).
    • Timing of blood in urine (prostatic/urethral causes).
    • Past medical history (UTIs, renal stones).
    • Medications (OTC, herbal), smoking status, sexual history (risk for STIs including HIV).
  • Diagnostics: Comprehensive physical exam (including pelvic/genital and rectal exams for men).
    • Minimum Tests: Urinalysis, urine CNS, urine cytology, CBC with diff, basic metabolic panel (BUN, creatinine).
    • Advanced Imaging: Ultrasound, CT, cystoscopy (if required).

Management

  • Depends on Cause: Driven by the underlying condition.
  • No Referral Needed: Isolated or transient hematuria, infection-based hematuria.
  • Red Flags for Referral/Urgent Care: Gross hematuria, severe flank pain, unstable vital signs, urologic obstruction (bladder distension, anuria), acute renal failure.

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