SHM Converge Scientific Abstract ePoster Gallery-It Wasn't the Prune Juice: Purple Urine Bag Syndrome in a Patient With Percutaneous Nephrostomy

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Purple Urine Bag Syndrome (PUBS) is a rare, usually benign condition seen most often in elderly, chronically catheterized patients, especially women and those with constipation, urinary tract infection, renal failure, or alkaline urine. It results from tryptophan metabolism: gut bacteria convert tryptophan to indole, which becomes indoxyl sulfate in the liver. In the setting of certain bacteria and alkaline urine, this is converted into purple pigments (indigo and indirubin). PUBS has also been linked to interactions between alkaline urine and plastic tubing/bags. Common organisms include E. coli, Klebsiella pneumoniae, Proteus mirabilis, and mixed flora.<br /><br />This case involved a 78-year-old woman with stage 4 chronic kidney disease, diet-controlled diabetes, and bilateral idiopathic ureteral obstruction treated with bilateral percutaneous nephrostomy tubes. She presented with 5 days of dark, thick urine that turned purple. She initially thought it was from drinking prune juice and also had constipation. She denied fever, pain, or reduced tube output, but had mild chills and fatigue. On exam, she was stable and the main finding was striking purple discoloration in the nephrostomy tubing and bag.<br /><br />Laboratory studies showed mild leukocytosis, a slight creatinine rise from baseline, alkaline urine (pH 8), pyuria, and bacteria. She was started on antibiotics and underwent nephrostomy tube exchange. The urine color normalized immediately after the procedure, even before antibiotics were given, and her kidney function and white count improved. Urine culture grew mixed bacterial flora, and she completed antibiotics after discharge.<br /><br />This case highlights that PUBS should be recognized as an uncommon but important sign of infection. Prompt identification can prevent delays in catheter exchange and treatment and avoid unnecessary workup for hematuria or other causes of discoloration.

Asset Subtitle

Rachel Bardowell

Meta Tag

Author List Rachel Bardowell

Category Clinical Vignettes

Concept Purple Urine Bag Syndrome

Concept Urinary Tract Infection

Concept Catheterization

Concept Tryptophan Metabolism

Concept Indoxyl Sulfate

Distinguished Non-Finalist

Presenter Organization Washington University in St. Louis

Presenting Author Rachel Bardowell

Track Adult

Keywords

Purple Urine Bag Syndrome

PUBS

catheter-associated infection

nephrostomy tube

elderly woman

alkaline urine

mixed bacterial flora

urinary tract infection

chronic kidney disease

indoxyl sulfate

Purple Urine Bag Syndrome

Urinary Tract Infection

Catheterization

Tryptophan Metabolism

Indoxyl Sulfate