Maria W. S. Tang

To the Editor: Purple urine bag syndrome (PUBS) is an uncommon but interesting condition that has been encountered in geriatric wards. Two patients with PUBS are described below, followed by a brief discussion of this condition. Patient 1 was a 70-year-old bedridden man who suffered from progressive paraplegia as a result of tuberculous meningitis and arachnoiditis. He required long-term urinary catheterization for urinary retention and had repeated urinary tract infections. Patient's condition was further complicated with a urethrocutaneous fistula that healed poorly, because he refused suprapubic catheterization to facilitate healing. He was chronically constipated and required habitual use of laxatives. After staying in a chronic care ward for 4 years, his urine bag, together with the drainage catheter, was noted to have purple discoloration for the first time (Figure 1). Patient was afebrile, and all vital signs were stable. His indwelling urinary catheter and drainage bag were changed, but the purple color appeared again shortly afterward. He developed fever 3 days later, and a sepsis examination was performed. Bedside urine Multistix revealed urine pH of 8.5, protein of 100 mg/dL, and was negative for leukocyte, red cells, nitrite, and glucose. Urine microscopy revealed moderate numbers (10,000–100,000 cells/mL) of leukocytes and grew Providencia species (>100, 000 colony forming units (CFU)/mL), whereas blood culture performed on the same day grew Proteus mirabilis. He was treated for urinary tract infection, according to the culture sensitivity results. The purple discoloration disappeared several weeks after antibiotic treatment. Purple discoloration of the urine drainage bag and tubing in purple urine bag syndrome. Patient 2 was an 81-year-old woman who became bed-ridden after a massive intracranial hemorrhage. She was receiving nasogastric tube feeding and had a long-term indwelling urinary catheter because of urinary retention. Nine months after her stroke, a nurse discovered that her urine bag had become purple, although her urine remained yellow but appeared turbid. Bedside urine Multistix revealed urine pH of 7.0, moderate numbers of leukocytes, and protein of 100 mg/dL, and was negative for nitrite and red cells. Patient developed fever 4 days later, and urine culture grew Enterococcus species (>100,000 CFU/mL). She was treated for urinary tract infection with a course of ampicillin. The purple discoloration disappeared shortly after antibiotic treatment. PUBS is an uncommon condition characterized by purple discoloration of urinary drainage bags. This clinical condition had been described as early as 19781 and was believed to be related to the metabolism of tryptophan.2 Bacterial metabolism of tryptophan by gut flora resulted in the production of indole, which in turn gave rise to indican after being conjugated in the liver.2 Indican was then excreted in the urine and digested into indoxyl by phosphatase/sulfatase produced from certain bacteria.2 Oxidation of free indoxyl in an alkaline environment produced two pigments—indigo and indirubin—which dissolved in the plastic of the urine bag and resulted in the purple discoloration.2 A number of PUBS-related factors had been described in the literature. Most patients reported with PUBS were debilitated3–5 women4–6 with long-term indwelling urinary catheters7 with chronic constipation.3,8 Urine alkalinity was believed to be an important promoting factor for PUBS.1–3,6 Bacteriuria had been implicated in PUBS, and only a few bacterial strains that contained indoxyl phosphatase (Providencia stuartii, Klebsiella pneumoniae, Enterobacter agglomerans) were initially reported to be capable of producing PUBS.2 Later, a case-control study demonstrated that, although 66 bacterial strains of 12 different species were isolated from the urine samples, no causative relationship between bacterial species and PUBS could be observed.6 Instead, higher bacterial count in urine was found to be the most important of all facilitating factors in PUBS.6 The cases presented had demonstrated various important contributing factors of PUBS discussed. Both cases appeared to be related to urinary tract infection, with their resolution shortly after antibiotic treatment. From literature search, PUBS appears to be a benign condition without major consequences,5,6,9 although because of its potential relationship with urinary tract infection, it is worthwhile for geriatricians to be aware of this condition. Financial Disclosure: None. Author Contributions: Maria W. S. Tang is the sole author of this letter. Sponsor's Role: None.

Abstract Background Frailty is associated with worse outcomes and higher healthcare costs. The long waiting time for surgery is a potential ‘teachable’ moment. We examined the feasibility and safety of a pilot prehabilitation programme on high-risk frail patients undergoing major elective surgery. Methods A single-centre, retrospective pilot study (Dec 2020–Nov 2021) on a one-stop prehabilitation programme (structured exercise training, nutritional counselling/therapy, and psychological support) in collaboration with geriatricians and allied health professionals. At least 4 weeks before surgery, patients at high risk of frailty or malnutrition, or undergoing major hepatectomy, esophagectomy, pancreaticoduodenectomy, or radical cystectomy, were referred for prehabilitation (2–3 sessions/week). The primary outcomes were the feasibility and safety of prehabilitation. The secondary outcomes were changes in functional, emotional, and nutritional status and days alive and at home within 30 days after surgery (DAH 30 ) associated with prehabilitation. Results Over a 12-month period, 72 out of 111 patients (64.9%) from the Perioperative Medicine Clinic were eligible for prehabilitation, of which 54 (75%) were recruited. The mean (standard deviation) age was 71.9 (6.9) years. The adherence rate to 3 weeks of prehabilitation was high in 52 (96.3%) participants. Prehabilitation improved exercise capacity ( P = 0.08), enhanced some functional mobility measures ( P = 0.02), and increased nutritional energy ( P = 0.04) and protein intakes ( P < 0.01). However, prehabilitation-related changes in muscle strength, cognitive function, and emotional resilience were minimal. The median (interquatile range) DAH 30 was 19 (14–23) days. No adverse events were reported. Conclusions This outpatient-based, one-stop multidisciplinary prehabilitation programme was feasible, safe, and improved several measures of patient’s physiological reserve and functional capacity. Clinical trial registration NCT05668221.

1. In subjects with sub-acute stroke, rehabilitation that combined transcutaneous electrical nerve stimulation (TENS) with task-oriented balance training (TOBT) was superior to placebo stimulation with TOBT in improving balance performance and motor functions.