Review article

The metabolic complications of urinary diversion

A nutritious diet has been associated with better health-related quality of life (HRQOL) in a variety of cancer survivors. However, little is known about dietary habits and its association with HRQOL in bladder cancer survivors. The objective of this cross-sectional study is to describe dietary intake patterns and its relationship to HRQOL in a large cohort of bladder cancer survivors.

Bladder cancer survivors within our institutional database were mailed surveys to assess dietary intake patterns utilizing the Diet History Questionnaire II and assessing HRQOL utilizing the Functional Assessment of Cancer Therapy-Bladder Cancer. Diet quality was assessed via Healthy Eating Index 2010 scores based on subjects’ Diet History Questionnaire II results. Univariate and multivariate analyses of HRQOL based on diet quality were used to evaluate whether diet quality was associated with HRQOL.

Four hundred and fifty-nine patients (48%) returned questionnaires. Mean age was 74 years, 81% were male and 28% underwent radical cystectomy. Diet quality and quantity in our cohort was similar to the general older U.S. population and did not differ significantly between those managed conservatively or long-term following cystectomy. Our cohort had low intake of whole grains and fat-soluble vitamins, particularly vitamin D. Diet quality was significantly associated with HRQOL in the univariate analysis but lost statistical significance in our multivariate analysis. Elixhauser Comorbidity Index was significantly associated with HRQOL in the multivariate analysis.

This study demonstrates a similar diet quality of bladder cancer survivors to the older general U.S. population that, on average, “needs improvement.” Dietary intake is particularly lacking in whole grain and vitamin D intake. Future studies are warranted to determine the impact on long-term outcome, but bladder cancer survivors should be counseled on the importance and benefits of adherence to dietary guidelines, including its potential contribution toward better HRQOL.

The differential diagnosis for a non-anion gap metabolic acidosis is probably less well known than the differential diagnosis for an anion gap metabolic acidosis. One etiology of a non-anion gap acidosis is the consequence of ileal neobladder urinary diversion for the treatment of bladder cancer.

We present a case of a patient with an ileal neobladder with a severe non-anion gap metabolic acidosis caused by a urinary tract infection and ureteroenterostomy.

Part of the ileal neobladder surgery includes ureteroenterostomy and predisposes patients to several clinically significant metabolic derangements, including a non-anion gap metabolic acidosis. These patients have an increased chronic acid load, bicarbonate deficit, and hypokalemia, which should be appreciated when resuscitating these patients.

To characterize the standard physical, chemical, and microscopic characteristics of urine in patients with noncomplicated orthotopic ileal neobladders.

This is a prospective study that included 100 male patients who underwent radical cystectomy and ileal neobladder between 1993 and 2013. All included patients were in a good health and having satisfactory function of the reservoirs with normal upper tract with a minimum 1-year postoperative follow-up. We excluded patients with oncological failure, those with diversion-related complications, those who were maintained on clean intermittent catheterization, or those who have symptoms of urinary tract infection. Patients with medical diseases that may affect urine properties (eg, diabetes mellitus) or receiving special medications (eg, diuretics, alkali therapy, or antibiotics) were also excluded. The patients were subjected to urine analysis, blood chemistry, pH, and blood gases; the results were compared to a control group of 40 normal male volunteers.

Urine analysis in diverted patients showed higher urine pH than in control group but it is still acidic. Pyuria, proteinuria, hematuria, and positive culture were significantly higher in diverted patients. The chemical analysis showed lower urinary calcium, phosphorus, and creatinine contents in diverted patients than in the control group. Serum creatinine was significantly higher in diverted patients, whereas blood pH and bicarbonate were lower, but these values are within normal.

Urine from uncomplicated orthotopic ileal reservoirs is acidic. Pyuria, proteinuria, minor degrees of microscopic hematuria, and positive nitrite reaction are normal findings. We also have normal findings for lower urinary calcium, phosphorus, and creatinine contents in patients.

La acidosis metabólica hiperclorémica es una complicación de las derivaciones urinarias que utilizan ileon o colon, y su prevalencia oscila entre el 25% y 46% de los casos, dependiendo de la técnica utilizada y de la función renal del paciente. Es una consecuencia del intercambio hidroelectrolítico entre la mucosa intestinal y la orina, siendo su mecanismo principal la absorción del amonio y cloruro de la orina. A largo plazo la acidosis metabólica crónica puede conllevar una alteración del metabolismo óseo y producir osteomalacia, por lo que la monitorización del pH, cloro, bicarbonato y metabolismo fosfocálcico es fundamental para un diagnóstico y tratamiento precoz.

Hyperchloremic metabolic acidosis is a complication of urinary diversion using ileum or colon. Its prevalence ranges from 25% and 46% depending on the procedure used and renal function of the patient. It is a consequence of intestinal fluid and electrolyte exchange between intestinal mucosa and urine. The main mechanism is absorption of ammonium and chloride from urine. Long-term chronic metabolic acidosis in these patients may lead to impaired bone metabolism and osteomalacia. Regular monitoring of pH, chlorine, bicarbonate, and calcium-phosphorus metabolism is therefore essential for early diagnosis and treatment.

Poor preoperative nutritional status is a risk factor for adverse outcomes after major surgery. We evaluated the effect of preoperative nutritional deficiency on perioperative mortality and overall survival in patients undergoing radical cystectomy for bladder cancer.

A total of 538 patients underwent radical cystectomy for urothelial carcinoma between January 2000 and June 2008, and had nutritional parameters documented. Patients with preoperative albumin less than 3.5 gm/dl, body mass index less than 18.5 kg/m² or preoperative weight loss greater than 5% of body weight were considered to have nutritional deficiency. Primary outcomes were 90-day mortality and overall survival. Survival was estimated using Kaplan-Meier analysis and compared using the log rank test. Cox proportional hazards models were used for multivariate survival analysis.

Of 538 patients 103 (19%) met the criteria for nutritional deficiency. The 90-day mortality rate was 7.3% overall (39 deaths), with 16.5% in patients with nutritional deficiency and 5.1% in the others (p <0.01). Nutritional deficiency was a strong predictor of death within 90 days on multivariate analysis (HR 2.91; 95% CI 1.36, 6.23; p <0.01). Overall survival at 3 years was 44.5% (33.5, 54.9) for nutritionally deficient patients and 67.6% (62.4, 72.2) for those who were nutritionally normal (p <0.01). On multivariate analysis nutritional deficiency cases had a significantly higher risk of all cause mortality (HR 1.82; 95% CI 1.25, 2.65; p <0.01).

Nutritional deficiency, as measured by preoperative weight loss, body mass index and serum albumin, is a strong predictor of 90-day mortality and poor overall survival. Prospective studies are needed to demonstrate the best indices of preoperative nutritional status and whether nutritional intervention can alter the poor prognosis for patients treated with radical cystectomy who have nutritional deficiencies.