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Abstract: SA-PO1027

Purple Haze: An Uncommon Presentation of a Common Condition

Session Information

Category: Pathology and Lab Medicine

  • 1800 Pathology and Lab Medicine


  • Schwarz, Alexandra, Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Batwara, Ruchika, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Urine discoloration is a well-known clinical sign that often indicates an underlying pathology. However, purple-colored urine is a visually striking and rarely observed phenomenon that can cause great concern for patients and healthcare workers when encountered.

Case Description

An 80-year-old man with a chronic suprapubic urinary catheter presented with altered mental status following a fall. The patient's catheter was draining purple urine on arrival (as seen in Figure 1). Initial labs showed acute kidney injury (creatinine: 9.55 mg/dL) with previously normal creatinine at baseline, mild rhabdomyolysis (peak creatine phosphokinase: 2,734 U/L), and leukocytosis (white blood cells: 16.3 K/uL). Urinalysis revealed a large amount of leukocyte esterase and >182 white blood cells per high-power field. Renal and bladder imaging did not show any obstruction. The patient was managed as presumed urosepsis and promptly treated with meropenem and vancomycin, fluid resuscitation, and replacement of the suprapubic catheter. Antibiotics were started before sending cultures, so there was no growth observed in urine and blood cultures. The urinary catheter was draining yellow urine the following day and renal function returned to baseline during hospitalization.


Purple Urinary Bag Syndrome (PUBS) is a rare phenomenon caused by certain bacteria that produce enzymes that metabolize tryptophan into indigo (blue) and indirubin (red) pigments, resulting in purple urine color. Risk factors include old age, female gender, alkaline urine, constipation, and the use of plastic urinary bags.
The discoloration itself is benign but timely recognition of this uncommon presentation of urinary tract infection is crucial to ensure prompt diagnosis and treatment while avoiding unnecessary investigations.

Figure 1