Purple Haze as a Tell-Tale Sign: A Case Report

Patients with urinary tract infection (UTI) symptoms report dysuria, urinary frequency, fever, and/or urinary urgency.In addition, those with catheter-associated UTIs may have flank pain or suprapubic or costovertebral tenderness.We present a case of a rare physical examination finding that can also aid in the diagnosis of a catheter-associated UTI: purple urine bag syndrome (PUBS).An 84-year-old man with a past medical history of metastatic prostate cancer complicated by a rectourethral fistula, status post ileal conduit and loop colostomy, presented after his daughter noticed what she believed was blood in the overnight drainage bag connected to his ileal conduit.The patient had previously required bilateral percutaneous nephrostomy tubes for malignant extrinsic ureteral compression from progressive prostate cancer, but the right nephrostomy tube had subsequently been removed after identifying that the left-sided obstruction was the culprit.The patient was reporting right-sided abdominal pain and fatigue.On examination, the patient was lethargic and unable to provide a history.Examination revealed dark purple discoloration of the ileal conduit tubing and overnight drainage bag.A Foley catheter placed by the emergency department did not drain urine because of the patient's ileal conduit and was subsequently removed.Urinalysis did not demonstrate hematuria, indicating that the discoloration perceived as blood was the purple hue shown in the clinical photograph.Urine specimens were obtained from the functioning urinary drainage sites, and the culture obtained from the ileal conduit collection bag was positive.The patient was started on ertapenem and daptomycin due to a history of severe sepsis secondary to vancomycin-resistant Enterococcus (VRE) UTI from his ileal conduit and extended-spectrum beta-lactamase-producing (ESBL) Escherichia coli from his catheter site.CT of the abdomen and pelvis demonstrated hydronephrosis of the right kidney with concern for developing pyelonephritis.The right-sided hydronephrosis was attributed to malignant extrinsic ureteral compression from progressive prostate cancer.The urine culture from the ileal conduit collection bag grew Providencia stuartii, Proteus mirabilis, E. coli, and Pseudomonas aeruginosa, all of which were susceptible to meropenem.Due to concern for pyelonephritis and a rise in the patient's creatinine, a right-sided percutaneous nephrostomy (PCN) tube was placed, and the patient's condition improved after a six-day course of meropenem.This case is notable for purple discoloration of the ileal conduit tubing and overnight collection bag, consistent with PUBS.This syndrome is associated with UTIs in elderly people, particularly those who are constipated.The source of the pigment has been attributed to altered tryptophan metabolism related to prolonged intestinal transit time and the production of indole derivatives by bacteria.The tryptophan metabolites produce red and blue pigments that combine to form the purple color seen in PUBS.In this patient, the culture obtained from the ileal conduit collection bag grew predominantly Providencia stuartii and Proteus mirabilis, both of which have been implicated in this syndrome.The patient's right-sided hydronephrosis occurred in the setting of malignant extrinsic ureteral compression from progressive prostate cancer rather than obstruction of the bladder or urethra.