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Renal Function & Metabolic Surveillance After Bowel-Based Reconstruction

Longitudinal renal-function and metabolic testing is the main laboratory surveillance after a procedure that interposes intestinal mucosa into the urinary tract or that risks silent obstructive uropathy. Bowel-incorporating augmentation and urinary diversions can cause metabolic complications.[1][2][3] Advanced prolapse and high-risk NLUTD with high storage pressures or VUR can threaten the upper tracts before symptoms develop.[5][31] Serum creatinine with eGFR anchors renal surveillance; a BMP or CMP is used when bowel is incorporated into the urinary tract or another metabolic indication exists. B12 and bone testing, the surveillance schedule and thresholds for action depend on the reconstruction and clinical risk.[4][6][27][28]

Serum Creatinine and Estimated GFR​

Serum creatinine and a creatinine-based eGFR are the baseline renal-function tests for any reconstructive patient. KDIGO 2024 recommends creatinine-based eGFR initially and, when cystatin C is available, estimating the GFR category with the combined creatinine–cystatin C equation. Use additional assessment when non-GFR determinants of either marker or a treatment decision require greater accuracy.[4]

Indications for baseline and serial eGFR monitoring:

  • Advanced pelvic organ prolapse. A prospective 180-woman cohort with POP-Q C, Aa, or Ba ≥+1 found hydronephrosis in 55 women (30.6%).[5] Consider upper-tract imaging and renal assessment when advanced prolapse may impair drainage.[5]
  • Neurogenic LUTD. AUA/SUFU 2021 NLUTD guideline (Statements 14 and 15; Moderate Recommendations, Grade C) recommends annual renal-function assessment in stable moderate- and high-risk patients, with upper-tract imaging every 1 to 2 years (moderate risk) or annually (high risk).[31] EAU 2026 guidance describes upper-tract ultrasonography approximately every six months for high-risk neurologic patients and grades regular upper-tract assessment as Strong.[37]
  • Augmentation cystoplasty. Lifelong surveillance is needed after augmentation for NLUTD.[6] In Cheng's retrospective 40-patient augmentation cohort (median follow-up 13 years), mean eGFR did not change significantly from before surgery to follow-up (68.3 versus 76.6 mL/min; p = 0.798).[13]
  • Pre-cystectomy / pre-diversion baseline. NICE advises considering a post-cystectomy follow-up protocol with upper-tract imaging and GFR estimation at least annually[7]; early postoperative and abnormal results may warrant more frequent assessment. Nishikawa's 169-patient series (median 106-month follow-up) documented an eGFR drop from 69.6 to 55.9 mL/min/1.73 m², with renal deterioration (>25% eGFR decline) in 57% of ureterostomy, 50% of ileal conduit, and 39% of neobladder patients, but on multivariable analysis, hypertension and acute pyelonephritis episodes, not diversion type, were the independent predictors of decline.[12] This observational association supports attention to hypertension and febrile UTI. A separate long-term analysis restricted to patients with preoperative CKD stage 2 or 3a (1,383 patients: 1,021 incontinent and 362 continent diversion; median follow-up 11.2 years) found that the risk of eGFR decline over 10 years did not differ significantly between incontinent and continent diversion, across multiple decline definitions.[34]
  • Any major reconstructive procedure. A baseline eGFR before pyeloplasty, ureteral reimplant, urinary diversion, or augmentation cystoplasty anchors longitudinal interpretation.

Segment selection with CKD. Reduced renal reserve increases vulnerability to the acid load from bowel exposed to urine. Evaluate renal trajectory, drainage, bowel segment and contact time together. Gastric augmentation has distinctive acid-secretion and long-term complication concerns.[8][9]

Pitfalls in eGFR Interpretation in the Reconstructive Population​

Creatinine-based eGFR is the usual test, but the reconstructive population concentrates several conditions in which the equation systematically misleads.

  • Bowel exchange of creatinine. Intestinal segments can reabsorb urinary creatinine, returning it to the circulation and reducing the amount recovered in a timed urine collection. Reabsorption can raise serum creatinine and lower apparent clearance; its magnitude depends on urine flow and contact with bowel. A canine ileal-interposition study demonstrated flow-dependent reabsorption, while a small human neobladder study found both resorptive and excretory patterns. Do not apply a uniform correction factor to eGFR or assume that a timed urine clearance is free of bowel-related bias.[14][23][24]
  • Spinal cord injury and other low-muscle-mass states. Reduced muscle mass can make serum creatinine deceptively low and creatinine-based eGFR overestimate GFR. In spinal cord injury without other major illness, cystatin C-based eGFR may be appropriate; with comorbidity, KDIGO suggests the combined creatinine–cystatin C estimate. Consider measured GFR when drug dosing, contrast, or operative decisions require greater accuracy.[15][4]
  • Drug-dosing decisions near a renal-function threshold. When creatinine-based eGFR is discordant with the clinical setting, consider cystatin C with a combined equation, or measured GFR when greater accuracy would change treatment. Bowel solute exchange also complicates timed urinary clearance; a 24-hour collection is not automatically a definitive solution after diversion.[4][23]

Basic / Comprehensive Metabolic Panel After Bowel-Based Reconstruction​

The BMP (or CMP) is the core test of post-reconstruction surveillance whenever bowel is interposed in the urinary tract. AUA/SUFU recommends annual BMP, focused assessment and urinary-tract imaging for NLUTD patients with bowel-segment lower-tract reconstruction .[6] After treatment for muscle-invasive bladder cancer, the AUA/ASCO/SUO guideline advises laboratory assessment every 3 to 6 months for 2 to 3 years and then annually ; its discussion cites declining renal function after urinary diversion, electrolyte and acid-base abnormalities that vary with the bowel segment, and B12 deficiency risk after resection of more than 60 cm of ileum or use of the terminal ileum.[32] NCCN uses renal-function testing with electrolytes and creatinine every 3–6 months in year 1 after cystectomy for NMIBC or MIBC, then annually in years 2–5 (category 2A).[35] NICE advises considering a post-cystectomy follow-up protocol with at least annual monitoring for metabolic acidosis and both B12 and folate deficiency.[7] Frequency outside these populations depends on clinical risk and postoperative course.[7]

The three classic derangements​

DerangementMechanismFrequencyManagement
Hyperchloremic metabolic acidosisIleal and colonic mucosa absorb urinary chloride and ammonium in exchange for sodium and bicarbonate; prolonged stasis amplifies absorptionReported frequency varies with segment, follow-up and definition; risk rises with renal dysfunction[8]Choose alkali according to renal function, potassium and volume status; potassium-containing agents can be inappropriate with hyperkalemia/advanced CKD. KDIGO gives adult CKD HCO₃⁻ <18 mmol/L as one example of clinically important acidosis[4]; assess drainage and emptying
HypokalemiaIntestinal potassium secretion + renal wasting in the setting of acidosisCan occurReplace documented deficits and monitor potassium during alkali treatment; potassium citrate is an option only when renal/potassium status permits
HyponatremiaSodium-chloride loss into urine through a jejunal segment[17]Characteristic of jejunal conduit syndrome rather than a general bowel-diversion effectAssess severity, chronicity, volume status and cause; avoid an automatic salt prescription or rapid correction

Gastric urinary reconstruction can cause hypochloremic, hypokalemic metabolic alkalosis or hematuria-dysuria syndrome and has important long-term safety concerns.[38][9] A selected 29-patient gastric-reconstruction series reported three reservoir malignancies at 11–14 years; the rate above 10% applies to that cohort.[9]

Bowel-segment-specific physiology​

The pattern, severity, and even the direction of the metabolic derangement depend on which bowel segment was used. Surveillance labs are interpreted against the signature of the segment used.

SegmentElectrolyte / acid-base signatureMechanismComment
Ileum / colon (most common)Hyperchloremic non-anion-gap metabolic acidosis; potassium may be low, normal or highCl⁻/HCO₃⁻ exchange + NH₄⁺/K⁺ exchange across colonic and ileal mucosa; longer segment and longer dwell time amplify the acid loadDefault expected pattern for ileal conduit, ileal/colonic neobladder, ileocecal continent reservoir, and ileal augmentation
JejunumHyponatremic, hypochloremic, hyperkalemic metabolic acidosis ("jejunal conduit syndrome")Jejunal mucosa actively secretes NaCl and absorbs K⁺ and urea, the opposite of ileal/colonic transportCan be life-threatening, especially with impaired renal reserve; largely abandoned for routine diversion[16][17][18]
StomachHypochloremic, hypokalemic metabolic alkalosis, plus hematuria-dysuria syndromeGastric mucosa secretes HCl into the urineRarely used today; malignancy signal further restricts use

Hyperkalemia can occur despite an ileal or colonic segment. Assess AKI or CKD, obstruction, potassium intake or supplements and potassium-raising drugs, as well as adrenal causes, the actual segment and sample artifact. Urgent assessment and treatment must not wait for a presumed bowel explanation when potassium is dangerously elevated.[4]

Risk factors for persistent acidosis​

Lockhart's prospective 31-patient series reported hyperchloremic acidosis in 35.2% of patients with long detubularized segments.[1] In the orthotopic bladder-replacement group, 1 of 6 patients (16.7%) had hyperchloremia as the sole metabolic derangement.[1] Kim's 123-patient neobladder cohort defined acidosis as bicarbonate below 22 mEq/L and impaired renal function as GFR below 50 mL/min.[19] Impaired renal function predicted acidosis at one month; diabetes predicted it at one year (OR 5.68), and age and diabetes at two years.[19] The study used an approximately 60-cm ileal segment.[19]

Surveillance cadence​

  • Early recovery, changing renal function or treatment adjustment: check renal function and electrolytes at intervals appropriate to the operation and abnormality.
  • Stable long-term follow-up: at least annual renal and metabolic assessment in the guideline populations above; increase frequency with CKD, obstruction, incomplete emptying or persistent acidosis.[6][7]
  • New symptoms: fatigue, weight loss, growth concerns or bone pain warrant clinical assessment and targeted testing. An off-cycle metabolic panel may be appropriate; DXA depends on the bone-risk question rather than symptoms alone.[4][28]

Confirm a persistent bicarbonate abnormality and assess renal function, drainage, reservoir emptying, symptoms and other acid-base causes. KDIGO 2024 Practice Point 3.10.1 advises considering treatment for acidosis with potential clinical implications in people with CKD, giving adult bicarbonate <18 mmol/L as an example; it does not establish an automatic treatment threshold of 22 mmol/L or a universal diversion-specific cutoff. Individualize alkali and monitor blood pressure, potassium, fluid status and bicarbonate to avoid overtreatment. The urinary acidifiers and alkalinizers hub covers agent selection.[4]

Vitamin B12 Surveillance​

The terminal ileum is the principal site of intrinsic-factor-mediated B12 absorption. Risk after ileal reconstruction depends on the location and length removed from the alimentary stream, remaining bowel health, diet, and other causes of malabsorption. Potentially relevant procedures include:

  • Ileal conduit
  • Ileal orthotopic neobladder (Studer, Hautmann, T-pouch)
  • Continent cutaneous reservoirs incorporating ileum (Indiana pouch, Mainz I, Kock)
  • Augmentation cystoplasty using ileum or ileocecal segment
  • Catheterizable channels using ileum (Monti, Yang–Monti, Casale spiral)

What to measure​

Use total or active B12 as the usual initial test. MMA can help resolve an indeterminate result with compatible symptoms, but renal impairment itself raises MMA; homocysteine is also affected by renal function and folate status. Neither metabolite is independently diagnostic in CKD.[25][26] In Sagalowsky's 41-patient diversion study, a combined B12, MMA and homocysteine profile suggested more tissue deficiency than serum B12 alone.[10] Among 94 of 458 Mainz I pouch patients reevaluated after at least five years (median nine), Pfitzenmaier et al. recommended supplementation in 32% because levels were low-normal or below normal.[11] Davidsson et al. found subnormal B12 in five of 39 long-term diversion patients with preserved renal function.[2]

Surveillance schedule​

  • After cystectomy with bowel diversion: measure B12 annually (EAU bladder cancer guideline text); obtain earlier tests for pre-existing deficiency, anemia or neurologic symptoms.[7][27]
  • NCCN post-cystectomy follow-up: B12 is measured annually after the first year, based on clinical judgment (category 2A).[35]
  • Other ileal reconstructions: individualize timing to the amount and location of ileum used and clinical risk.
  • Indeterminate B12 with symptoms: consider MMA with renal function and the laboratory range in mind. Draw diagnostic bloods before replacement when feasible; NICE advises treatment before initial results when suspected megaloblastic anaemia and neurologic symptoms coexist.[25] After an indeterminate B12 result, consider replacement while awaiting MMA if symptoms may deteriorate rapidly or terminal-ileal resection has occurred.[25][26]

When to supplement​

Replace confirmed deficiency; start promptly when neurologic or hematologic findings make delay unsafe. NICE recommends lifelong intramuscular replacement after complete terminal-ileal resection. For confirmed B12 deficiency caused by other malabsorption, NICE advises offering replacement and considering intramuscular rather than oral administration; if oral treatment is chosen for confirmed or suspected malabsorption, prescribe at least 1 mg/day and review clinical response.[25] A maintenance injection interval alone is not an adequate loading regimen for symptomatic deficiency.[25]

Detailed dosing, monitoring intervals by segment length, and route selection are covered in the Vitamin B12 Supplementation pharmacology hub.

Bone Density and Metabolic Bone Labs​

Chronic hyperchloremic acidosis after bowel-based reconstruction can contribute to demineralization alongside CKD, age, endocrine factors and nutritional status. Bone buffering is one mechanism by which chronic acidosis may contribute to demineralization.[20] Impaired growth has been described in children after urinary intestinal reconstruction.[33] Adult fracture risk is associated with diversion in observational cohorts.[21]

Pathophysiology​

Chronic acidosis can contribute to bone mineral loss. McDougal and Koch documented mineral abnormalities in patients with intestinal urinary diversion and used rat experiments to examine mechanisms: reabsorbed ammonium and sulfate can inhibit renal tubular calcium and magnesium reabsorption, increasing urinary losses. Bone risk assessment must also account for renal disease, age and other skeletal risk factors.[20]

Population-based fracture risk​

Richard et al. studied 4,301 bladder-cancer and 907 non-bladder-cancer diversion patients, each group matched to controls, using linked Ontario administrative data. Fracture rates were significantly elevated in diverted patients (4.41 versus 2.63 per 100 person-years in the bladder-cancer cohort; 5.67 versus 3.51 in the non-bladder-cancer cohort). On multivariable analysis, intestinal urinary diversion was associated with shorter fracture-free survival versus matched controls in both the bladder-cancer cohort (HR 1.48) and the non-bladder-cancer cohort (HR 1.48), across ages.[21]

Bone turnover markers — interpretation and timing​

Kawakita's serial measurements documented that urinary pyridinium cross-links (deoxypyridinoline, a bone resorption marker) peak immediately postoperatively and gradually decrease to a stable level over 1–2 years, suggesting an early acute resorptive phase followed by a chronic plateau.[22] KDIGO 2017 distinguishes tests: in CKD G3a–G5D, PTH or bone-specific alkaline phosphatase may help assess turnover (2B), whereas routine collagen synthesis or breakdown markers are not suggested (2C). BMD testing is suggested when CKD-MBD or osteoporosis risk is present and the result will affect treatment.[28]

Markers studied in long-term diversion follow-up​

  • Bone-specific alkaline phosphatase. Formation marker.
  • Osteocalcin. Formation marker.
  • Cross-linked telopeptides (CTX, "cross-laps"). Resorption marker.
  • 25-hydroxyvitamin D. Substrate adequacy.
  • Calcium, phosphate, magnesium, PTH. Companions to the BMP.

Stein's 27-patient observational series used dual-photon absorptiometry: BMD was normal in 25 evaluable patients managed with early base-excess correction; two could not be measured accurately.[3] Pfitzenmaier reported that approximately 37% of the 94 Mainz I ileocecal pouch patients reevaluated after at least five years were taking sodium or potassium citrate to prevent acidosis at follow-up.[11]

Practical surveillance​

  • Assess fracture risk, persistent acidosis, nutrition and CKD-MBD together; obtain DXA when its result will change management.
  • Individualize repeat DXA to baseline findings, treatment and evolving risk. A fixed two-to-three-year schedule is not established for every diverted patient.
  • Correct clinically important acidosis and monitor treatment as above.[4][20][28]

Alkali agent selection (sodium citrate versus potassium citrate versus bicarbonate, dosing, and the controversy around ascorbic acid) is covered in the Urinary Acidifiers & Alkalinizers pharmacology hub.

A Note on Liver Function Tests​

Coordinate cancer-specific imaging and laboratory surveillance with the treating oncology team and the applicable guideline. Innon-oncologic reconstruction, order liver tests according to symptoms, comorbidity and the differential diagnosis.

Ammoniagenic Encephalopathy​

Hyperammonemic encephalopathy can complicate bowel-based diversion even without established liver disease. New unexplained altered mental status warrants urgent assessment, including ammonia when clinically suspected, renal and hepatic testing, infection evaluation and assessment of drainage. Treat a contributing symptomatic infection and relieve obstruction or poor reservoir emptying; ammonia-lowering treatment requires coordination with the acute-care team. Antibiotics are not indicated merely for asymptomatic pouch colonization. In two reported patients with recurrent infection-associated encephalopathy, diversion revision to improve drainage and shorten urine–bowel contact resolved symptoms; management evidence remains case-based.[29][30]

Chologenic (Bile-Acid) Diarrhea​

Diarrhea can be particularly bothersome after urinary diversion.[33] When a substantial length of preterminal ileum is resected for the diverted segment, reduced bile-acid reabsorption allows more bile acids to reach and irritate the colon, causing diarrhea. Fat malabsorption with steatorrhea may also occur when larger portions of small intestine are resected.[33]

For persistent bothersome diarrhea after urinary diversion suspected to reflect bile-acid malabsorption, assess ileal-resection extent, ileocecal-valve loss, and steatorrhea before considering cholestyramine.[33] After terminal-ileal resection, test symptomatic patients for bile-acid malabsorption when available or consider a sequestrant trial if testing is unavailable.[39] With extensive ileal loss and steatorrhea, cholestyramine may increase fat and calorie loss.[40] In selected patients, cholestyramine may start at 4 g twice daily and increase gradually to 8 g twice daily; give other oral medicines at least 1 hour before or 4–6 hours after it, and monitor for fat-soluble vitamin deficiency during prolonged use.[33][36] Prolonged cholestyramine use may cause hyperchloremic acidosis; use caution with renal insufficiency, volume depletion, or spironolactone.[36] A gut-motility inhibitor such as loperamide, 4 to 16 mg per day, can be added for persistent diarrhea, and increased dietary fiber can slow transit.[33] Fluid restriction is not advised, because patients with a urinary diversion are already prone to dehydration.[33]

Putting It Together — Annual Reconstructive Lab Visit​

A framework for stable long-term follow-up; apply bowel-related BMP and B12 rows only to indicated reconstructions, and adapt renal testing to the underlying renal risk. An isolated catheterizable channel without augmentation does not itself require annual BMP testing for bowel-related acid-base risk.[6]

LabCadenceWhat is tracked
Serum creatinine + eGFRAnnualRenal function trajectory and CKD progression; assess possible obstruction with upper-tract imaging according to reconstruction and risk[6][7]
BMP / CMPAnnualPersistent bicarbonate abnormality prompts assessment; individualize alkali, potassium and volume management
Vitamin B12 and folate (MMA selectively if B12 is indeterminate)NICE advises considering a post-cystectomy protocol that monitors for B12 and folate deficiency at least annually[7]; EAU calls for annual B12 measurement after cystectomy with bowel diversion[27]; individualize for other ileal proceduresB12 and folate status; interpret B12 metabolites with renal function
25-OH vitamin D, calcium, phosphate ± PTHBased on CKD stage, nutritional/bone risk and prior resultsMineral and bone disease; risk-based interval
DXAWhen results affect treatment; repeat individualizedFracture risk and treatment response
Urine cultureSymptom-driven (not routine for asymptomatic colonized pouch)UTI vs colonization — see Urine Studies
LFTsAs clinically indicated or under the oncology planLiver disease, treatment effects or cancer-related concerns

Arrange earlier or more frequent tests for clinical abnormalities and postoperative risk.[6][7]

See Also​

References​

1. Lockhart JL, Davies R, Persky L, Figueroa TE, Ramirez G. "Acid-base changes following urinary tract reconstruction for continent diversion and orthotopic bladder replacement." J Urol. 1994;152(2 Pt 1):338–342. doi:10.1016/s0022-5347(17)32734-9

2. Davidsson T, Lindergård B, Månsson W. "Long-term metabolic and nutritional effects of urinary diversion." Urology. 1995;46(6):804–809. doi:10.1016/S0090-4295(99)80348-3

3. Stein R, Fisch M, Andreas J, Bockisch A, Hohenfellner R, Thüroff JW. "Whole-body potassium and bone mineral density up to 30 years after urinary diversion." Br J Urol. 1998;82(6):798–803. doi:10.1046/j.1464-410x.1998.00874.x

4. Stevens PE, Ahmed SB, Carrero JJ, et al. "KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease." Kidney Int. 2024;105(4S):S117–S314. doi:10.1016/j.kint.2023.10.018

5. Dancz CE, Walker D, Thomas D, Özel B. "Prevalence of Hydronephrosis in Women With Advanced Pelvic Organ Prolapse." Urology. 2015;86(2):250–254. doi:10.1016/j.urology.2015.05.005

6. Ginsberg DA, Boone TB, Cameron AP, et al. "The AUA/SUFU Guideline on Adult Neurogenic Lower Urinary Tract Dysfunction: Treatment and Follow-Up." J Urol. 2021;206(5):1106–1113. doi:10.1097/JU.0000000000002239

7. NICE. Bladder cancer: diagnosis and management, NG2, recommendation 1.6.1. Follow-up after radical cystectomy. Accessed September 11, 2026.

8. McDougal WS. "Metabolic complications of urinary intestinal diversion." J Urol. 1992;147(5):1199–1208. doi:10.1016/S0022-5347(17)37517-1

9. Castellan M, Gosalbez R, Bar-Yosef Y, Labbie A. "Complications after use of gastric segments for lower urinary tract reconstruction." J Urol. 2012;187(5):1823–1827. doi:10.1016/j.juro.2011.12.105

10. Sagalowsky AI, Frenkel EP. "Cobalamin profiles in patients after urinary diversion." J Urol. 2002;167(4):1696–1700. doi:10.1016/S0022-5347(05)65180-4

11. Pfitzenmaier J, Lotz J, Faldum A, Beringer M, Stein R, Thüroff JW. "Metabolic evaluation of 94 patients 5 to 16 years after ileocecal pouch (Mainz pouch I) continent urinary diversion." J Urol. 2003;170(5):1884–1887. doi:10.1097/01.ju.0000091900.57347.ee

12. Nishikawa M, Miyake H, Yamashita M, Inoue TA, Fujisawa M. "Long-term changes in renal function outcomes following radical cystectomy and urinary diversion." Int J Clin Oncol. 2014;19(6):1105–1111. doi:10.1007/s10147-014-0661-y

13. Cheng KC, Kan CF, Chu PS, et al. "Augmentation cystoplasty: urodynamic and metabolic outcomes at 10-year follow-up." Int J Urol. 2015;22(12):1149–1154. doi:10.1111/iju.12943

14. Cruz DN, Huot SJ. "Metabolic complications of urinary diversions: an overview." Am J Med. 1997;102(5):477–484. doi:10.1016/S0002-9343(97)00020-X

15. Karger AB, Shlipak MG. "Glomerular Filtration Rate (GFR) Estimation with Cystatin C—Past, Present, and Future." Clin Chem. 2025;71(7):743–751. doi:10.1093/clinchem/hvae226

16. Golimbu M, Morales P. "Jejunal conduits: technique and complications." J Urol. 1975;113(6):787–795. doi:10.1016/s0022-5347(17)59581-6

17. Bonnheim DC, Petrelli NJ, Sternberg A, Mittelman A. "The pathophysiology of the jejunal conduit syndrome and its exacerbation by parenteral hyperalimentation." J Surg Oncol. 1984;26(3):172–175. doi:10.1002/jso.2930260307

18. Klein EA, Montie JE, Montague DK, Novick AC, Straffon RA. "Jejunal conduit urinary diversion." J Urol. 1986;135(2):244–246. doi:10.1016/s0022-5347(17)45598-4

19. Kim KH, Yoon HS, Yoon H, et al. "Risk Factors for Developing Metabolic Acidosis after Radical Cystectomy and Ileal Neobladder." PLoS One. 2016;11(7):e0158220. doi:10.1371/journal.pone.0158220

20. McDougal WS, Koch MO. "Effect of sulfate on calcium and magnesium homeostasis following urinary diversion." Kidney Int. 1989;35(1):105–115. doi:10.1038/ki.1989.15. PMID 2709657

21. Richard PO, Bashir S, Riverin BD, et al. "Risk of Bone Fractures Following Urinary Intestinal Diversion: A Population Based Study." J Urol. 2019;202(2):319–325. doi:10.1097/JU.0000000000000213

22. Kawakita M, Arai Y, Shigeno C, et al. "Bone demineralization following urinary intestinal diversion assessed by urinary pyridinium cross-links and dual energy X-ray absorptiometry." J Urol. 1996;156(2 Pt 1):355–359. doi:10.1016/S0022-5347(01)65849-X

23. Koch MO, McDougal WS. "Determination of renal function following urinary diversion through intestinal segments." J Urol. 1985;133(3):517–520. doi:10.1016/S0022-5347(17)49044-6. PMID 3974007

24. Rinnab L, Straub M, Hautmann RE, Braendle E. "Postoperative resorptive and excretory capacity of the ileal neobladder." BJU Int. 2005;95(9):1289–1292. doi:10.1111/j.1464-410X.2005.05521.x. PMID 15892819

25. NICE. Vitamin B12 deficiency in over 16s: diagnosis and management, NG239. Recommendations. 2024; accessed September 11, 2026.

26. NIH Office of Dietary Supplements. Vitamin B12 — Health Professional Fact Sheet. B12 and metabolite interpretation. Accessed September 11, 2026.

27. EAU. Muscle-invasive and Metastatic Bladder Cancer Guidelines, 2026. Functional follow-up.

28. KDIGO. 2017 CKD-MBD Guideline Update, recommendations 3.2.1, 3.2.3 and 3.2.4. Guideline.

29. Hyperammonemic encephalopathy in urinary diversion with urea-splitting urinary tract infection. Original report. 1990.

30. Coloma et al. Hyperammonemic encephalopathy due to a urinary diversion: an uncommon cause of reversible dementia. J Am Geriatr Soc. 2011. doi:10.1111/j.1532-5415.2011.03377.x.

31. Ginsberg DA, Boone TB, Cameron AP, et al. "The AUA/SUFU Guideline on Adult Neurogenic Lower Urinary Tract Dysfunction: Diagnosis and Evaluation." J Urol. 2021;206(5):1097–1105. doi:10.1097/JU.0000000000002235

32. Holzbeierlein J, Bixler BR, Buckley DI, et al. Treatment of Non-Metastatic Muscle-Invasive Bladder Cancer: AUA/ASCO/SUO Guideline (2017; Amended 2020, 2024). J Urol. 2024;212(1):3-10. doi:10.1097/JU.0000000000003981

33. Van der Aa F, Joniau S, Van Den Branden M, Van Poppel H. "Metabolic changes after urinary diversion." Adv Urol. 2011;2011:764325. doi:10.1155/2011/764325

34. Gershman B, Eisenberg MS, Thompson RH, et al. "Comparative impact of continent and incontinent urinary diversion on long-term renal function after radical cystectomy in patients with preoperative chronic kidney disease 2 and chronic kidney disease 3a." Int J Urol. 2015;22(7):651-656. doi:10.1111/iju.12770

35. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Bladder Cancer. Version 3.2026. August 6, 2026. BL-E 3–4 of 6; Discussion MS-16–17, MS-28. Guideline.

36. Par Health USA, LLC. Questran (cholestyramine for oral suspension USP): prescribing information. Updated April 17, 2026. DailyMed.

37. European Association of Urology. EAU Guidelines on Neuro-urology. 2026. Follow-up, §3.7.

38. Stein R, Rubenwolf P. "Metabolic Consequences after Urinary Diversion." Front Pediatr. 2014;2:15. doi:10.3389/fped.2014.00015

39. Lenti MV, Hammer HF, Tacheci I, et al. "European Consensus on Malabsorption—UEG & SIGE, LGA, SPG, SRGH, CGS, ESPCG, EAGEN, ESPEN, and ESPGHAN: Part 2: Screening, Special Populations, Nutritional Goals, Supportive Care, Primary Care Perspective." United European Gastroenterol J. 2025;13(5):773–797. doi:10.1002/ueg2.70011

40. Sadowski DC, Camilleri M, Chey WD, et al. "Canadian Association of Gastroenterology Clinical Practice Guideline on the Management of Bile Acid Diarrhea." J Can Assoc Gastroenterol. 2020;3(1):e10–e27. doi:10.1093/jcag/gwz038