Harvey's Garden

Urine color

2 min read

  • Dark Yellow / Orange
    • Physiologic: Dehydration (most common cause; ↑ urochrome concentration).
    • Pathologic: ↑ Conjugated bilirubin (e.g., biliary obstruction, hepatitis). Urine will foam when shaken.
    • Drugs: Rifampin, phenazopyridine (Pyridium), sulfasalazine.
  • Red / Pink
    • Pathologic:
      • Hematuria (intact RBCs): Glomerulonephritis (e.g., IgA nephropathy, post-strep GN), kidney stones, bladder cancer (painless), UTI, trauma, prostate issues (BPH, prostatitis).
      • Hemoglobinuria (lysed RBCs): Intravascular hemolysis (e.g., Paroxysmal Nocturnal Hemoglobinuria [PNH], G6PD deficiency crisis, autoimmune hemolytic anemia).
      • Myoglobinuria (muscle breakdown): Rhabdomyolysis (crush injury, severe exertion, statins). Key finding: Urine dipstick is positive for blood, but microscopy shows no RBCs.
      • Acute Intermittent Porphyria (AIP): Urine darkens to a “port-wine” color upon standing.
    • Drugs: Rifampin, doxorubicin, phenytoin.
    • Diet: Beets, blackberries, rhubarb.
  • Brown / Black
    • Pathologic:
      • Severe rhabdomyolysis or intravascular hemolysis.
      • Alkaptonuria (homogentisic acid oxidase deficiency): Urine is normal color initially but darkens upon exposure to air or alkali. Associated with ochronosis (dark pigment in cartilage/sclera) and arthritis.
      • Malignant melanoma (rarely, advanced disease can cause melanuria).
    • Drugs: Metronidazole, methyldopa, nitrofurantoin, primaquine.
  • Blue / Green
    • Pathologic: Pseudomonas UTI (produces pyocyanin).
    • Drugs: Propofol (“propofol infusion syndrome”), amitriptyline, indomethacin, cimetidine, methylene blue.
    • Diet: Asparagus.
  • Cloudy / White
    • Pathologic:
      • Pyuria: Indicates a UTI. Urine is cloudy due to WBCs. Sterile pyuria can be seen in tubulointerstitial nephritis or TB.
      • Chyluria: Lymphatic fluid in urine. Caused by lymphatic obstruction (e.g., filariasis from Wuchereria bancrofti, tumor). Milky appearance.
      • Crystals: Phosphate crystals in alkaline urine; urate crystals in acidic urine.
  • Purple
    • Pathologic:
      • Purple Urine Bag Syndrome: A rare finding in chronically catheterized, often constipated patients (esp. elderly females) with a UTI. Gram-negative bacteria (e.g., Providencia, Klebsiella, Pseudomonas) in alkaline urine produce indirubin (red) and indigo (blue), which mix in the plastic catheter bag and tubing to appear purple.

Graph View

Backlinks