Differential Diagnosis for Small Amounts of Blood in Urine

• Single most likely diagnosis
  • Urinary Tract Infection (UTI): This is often the most common cause of hematuria (blood in urine), especially in women. Bacteria in the urinary tract can cause inflammation, leading to bleeding.
• Other Likely diagnoses
  • Kidney Stones: Small stones can cause microscopic hematuria due to irritation of the urinary tract lining.
  • Benign Prostatic Hyperplasia (BPH): Enlargement of the prostate can cause urinary retention, leading to bleeding.
  • Menstrual Contamination: In women, menstrual blood can contaminate a urine sample, especially during menstruation.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Bladder Cancer: Although less common, bladder cancer can present with painless hematuria and must be ruled out, especially in smokers or those with a history of exposure to certain chemicals.
  • Kidney Cancer: Similar to bladder cancer, kidney cancer can cause hematuria and is critical to diagnose early.
  • Sickle Cell Disease or Trait: These conditions can cause hematuria due to sickling of red blood cells in the kidney.
• Rare diagnoses
  • Alport Syndrome: A genetic disorder affecting the type IV collagen in the kidneys, leading to hematuria and progressive kidney disease.
  • Goodpasture Syndrome: An autoimmune disease causing inflammation in the kidneys and lungs, which can present with hematuria.
  • Nutcracker Phenomenon: Compression of the left renal vein between the aorta and superior mesenteric artery, leading to hematuria due to renal vein thrombosis or rupture of thin-walled veins.