Colonic necrosis following sodium polystyrene sulfonate (Kayexalate)-sorbitol enema in a renal transplant patient. Report of a case and review of the literature

Comprehensive analysis of sodium polystyrene sulfonate-induced colitis: A systematic review

BACKGROUND

Sodium polystyrene sulfonate (SPS) is commonly prescribed for the management of hyperkalemia, a critical electrolyte imbalance contributing to over 800000 annual visits to emergency departments.

AIM

To conduct a systematic review of documented cases of SPS-induced colitis and assess its associated prognosis.

METHODS

Following the PRISMA-P guidelines, our study employed Medical Subject Headings and Health Sciences Descriptors, skillfully combined using Boolean operators, to conduct comprehensive searches across various electronic databases, including Scopus, Web of Science, MEDLINE (PubMed), BIREME (Biblioteca Regional de Medicina), LILACS (Latin American and Caribbean Health Sciences Literature), SciELO (Scientific Electronic Library Online), Embase, and Opengray.eu. Language criteria were confined to English, Spanish, and Portuguese, with no limitations on the publication date. Additionally, we manually scrutinized the reference lists of retrieved studies. To present our findings, we utilized simple descriptive analysis.

RESULTS

Our search strategy yielded a total of 442 references. After rigorous evaluation, we included 51 references, encompassing 59 documented cases of colitis. Predominant clinical presentations included abdominal pain, observed in 35 (60.3%) cases, and bloating, reported in 18 (31%) cases. The most frequently affected sites of inflammation were the cecum, rectum, and small intestine, accounting for 31%, 25.8%, and 22.4% of cases, respectively. Colonoscopy findings were described in 28 (48.2%) cases, and 29 (50%) of patients required surgical intervention. Among the subset of patients for whom outcome data was available, 39 (67.2%) experienced favorable outcomes, while 12 (20.6%) unfortunately succumbed to the condition. The mean time required for resolution was 36.7 d, with a range spanning from 1 to 120 d.

CONCLUSION

SPS demonstrates the capacity to effectively lower serum potassium levels within 24 h. However, this benefit is not without the risk of bowel injury. Our study highlights the absence of high-quality data pertaining to the incidence of adverse events associated with SPS usage, making it challenging to determine whether the potential risks outweigh the benefits. However, a significant mortality rate related to SPS-induced colitis was noted. Future investigations should prioritize randomized controlled trials with a sufficiently large patient cohort to ascertain the true utility and safety profile of this medication.

Hyperkalaemia in Heart Failure

Hyperkalaemia has become an increasingly prevalent finding in patients with heart failure (HF), especially with renin–angiotensin–aldosterone system (RAAS) inhibitors and angiotensin–neprilysin inhibitors being the cornerstone of medical therapy. Patients living with HF often have other comorbidities, such as diabetes and chronic kidney disease, which predispose to hyperkalaemia. Until now, we have not had any reliable or tolerable therapies for the treatment of hyperkalaemia to facilitate implementation or achievement of target doses of RAAS inhibition. Patiromer sorbitex calcium and sodium zirconium cyclosilicate are two novel potassium-binding resins that have shown promise in the management of patients predisposed to developing recurrent hyperkalaemia, and their use may allow for further optimisation of guideline directed medical therapy.

Pre-Transplant Plasma Potassium as a Potential Risk Factor for the Need of Early Hyperkalaemia Treatment after Kidney Transplantation: A Cohort Study

INTRODUCTION

Plasma potassium (K+) abnormalities are common among patients with chronic kidney disease and are associated with higher rates of death, major adverse cardiac events, and hospitalization in this population. Currently, no guidelines exist on how to handle pre-transplant plasma K+ in renal transplant recipients (RTR).

OBJECTIVE

The aim of this study is to examine the relation between pre-transplant plasma K+ and interventions to resolve hyperkalaemia within 48 h after kidney transplantation.

METHODS

In a single-centre cohort study, we addressed the association between the last available plasma K+ level before transplantation and the post-transplant need for dialysis or use of K+-lowering medication to resolve hyperkalaemia within 48 h after renal transplantation using multivariate logistic regression analysis.

RESULTS

151 RTR were included, of whom 51 (33.8%) patients received one or more K+ interventions within 48 h after transplantation. Multivariate regression analysis revealed that a higher pre-transplant plasma K+ was associated with an increased risk of post-transplant intervention (odds ratio 2.2 [95% CI: 1.1-4.4]), independent of donor type (deceased or living) and use of K+-lowering medication within 24 h prior to transplantation).

CONCLUSIONS

This study indicates that a higher pre-transplant plasma K+ is associated with a higher risk of interventions necessary to resolve hyperkalaemia within 48 h after renal transplantation. Further research is recommended to determine a cutoff level for pre-transplant plasma K+ that can be used in practice.

Rectal ulcer due to Kayexalate deposition - an unusual case

Sodium polystyrene sulfonate (PSP) or Kayexalate is a cation-exchange resin, widely used in the management of hyperkalaemia due to renal disease. A rare, yet potentially dangerous, adverse event related to sodium polystyrene sulfonate use is intestinal mucosal injury, especially in the colon. The injury to the gastrointestinal mucosa can range from mild and superficial to wall necrosis and bowel perforation. The mechanism that leads to mucosal damage remains unclear. However, it is believed that sorbitol, commonly given to counteract PSP's tendency to cause constipation, may play an important role in the development of gastrointestinal injury. Other potential risk factors are uraemia or end-stage renal disease, hemodynamic instability, solid organ transplantation, postoperative status and concomitant opioid administration. The authors present a case of diarrhoea and haematochezia after the administration of PSP without sorbitol, in a patient with hyperkalaemia due to acute kidney injury, in the absence of other risk factors. A colonoscopy was performed and revealed a rectal ulcer which histological findings were suggestive of mucosal injury due to Kayexalate deposition. This case supports the concept that this widely used drug can itself, without sorbitol, cause injury to the gastrointestinal wall. Even though this is a rare adverse effect, the widespread use of this medication may put a large population at risk.

Electrolyte and Acid-Base Disorders in the Renal Transplant Recipient

Kidney transplantation is the current treatment of choice for patients with end-stage renal disease. Innovations in transplantation and immunosuppression regimens have greatly improved the renal allograft survival. Based on recently published data from the Scientific Registry of Transplant recipients, prevalence of kidney transplants is steadily rising in the United States. Over 210,000 kidney transplant recipients were alive with a functioning graft in mid-2016, which is nearly twice as many as in 2005. While successful renal transplantation corrects most of the electrolyte and mineral abnormalities seen in advanced renal failure, the abnormalities seen in the post-transplant period are surprisingly different from those seen in chronic kidney disease. Multiple factors contribute to the high prevalence of these abnormalities that include level of allograft function, use of immunosuppressive medications and metabolic changes in the post-transplant period. Electrolyte disturbances are common in patients after renal transplantation, and several studies have tried to determine the clinical significance of these disturbances. In this manuscript we review the key aspects of the most commonly found post-transplant electrolyte abnormalities. We focus on their epidemiology, pathophysiology, clinical manifestations, and available treatment approaches.

Challenges in Diagnosing Medication Resins in Surgical Pathology Specimens: A Crystal-Clear Review Guide

CONTEXT

- Medication resins, including Kayexalate, sevelamer, and bile acid sequestrants, can be encountered in gastrointestinal tract specimens. Their classic histologic appearances have been well documented, but pathologist recognition of the resins is 75%, patient history is not always available, and atypical morphologic findings are sometimes present.

OBJECTIVE

- To offer a succinct overview of resins in the gastrointestinal tract, including typical and atypical appearances, in order to serve as a quick reference guide.

DATA SOURCES

- The study comprises published literature, survey data, and our personal experiences.

CONCLUSIONS

- Classic morphology is the benchmark for identifying these resins, but color, location, and fish scale pattern can deviate from the norm, making proper identification a challenge. Patient history should be sought whenever possible, and ancillary staining is an option when necessary. Additionally, the presence of resins should prompt the pathologist to search for potentially related diagnoses (namely, causes of diarrhea in patients on bile acid sequestrants and diagnoses associated with renal failure in patients on Kayexalate or sevelamer).

Colitis induced by sodium polystyrene sulfonate in sorbitol: A report of six cases

Drug-related injury has been noted in virtually all organ systems, and recognition of the patterns of injury associated with medication enables modification of treatment and reduces the morbidity associated with the side effects of drugs. With the large number of new drugs being developed, documentation of the morphology of the changes seen as an adverse effect becomes important to characterize the pattern of injury. The pathologist is often the first to identify these abnormalities and correlate them with a particular drug. Kayexalate or sodium polystyrene sulfonate (SPS), a linear polymer derived from polystyrene containing sulfonic acid and sulfonate functional groups is used to treat hyperkalemia. It is usually administered with an osmotic laxative sorbitol orally or as retention enema. This combination has been implicated in causing damage to different parts of the gastrointestinal (GI) tract especially the colon and causes an established pattern of injury, recognizable by the presence of characteristic crystals, is presented to create a greater awareness of the Kayexalate colitis. This entity should be included in the differential diagnosis of lower GI mucosal injury in a setting of uremia and hyperkalemia.

Resin-Induced Colonic Pseudotumor: Rare Complication from Chronic Use of Potassium Binders in a Hemodialysis Patient

Potassium-binding resins are widely used in the treatment of hyperkalemia, mostly in the acute setting. Gastrointestinal adverse events, although reported, are not frequently seen due to its short course of use. This report describes a case involving an end-stage renal disease patient on hemodialysis who developed a colonic mass after being on sodium polystyrene sulfonate chronically for persistent hyperkalemia. Gastrointestinal symptoms developed late during the treatment rather than early as reported previously in the literature. This mass was mistaken for a carcinomatous lesion, which initiated an extensive work-up as well as hospitalization that nearly resulted in a subtotal colectomy.

How Center Volumes Affect Early Outcomes in Acute Myeloid Leukemia

Early mortality (EM) is all too frequent during induction chemotherapy for acute myeloid leukemia. Older patients shoulder an undue amount of this burden as a result of the inherent biology of their disease and increased comorbidities. EM rates in academic centers have seen a sharp decline over the past 20 years; however, data from population-based registries show that EM rates for the general population have significantly lagged behind. In this review, we analyze the data available on EM in academic centers and the general population, explore recent improvements in supportive care and the use of predictive models, and finally investigate the relationship between case volume and complications during chemotherapy.

Kayexalate (Sodium Polystyrene Sulfonate) as a Hallmark and Cause of Gastrointestinal Tract Injury: Two Case Reports and a Review of the Literature

Kayexalate (sodium polystyrene sulfonate) is a cation exchange resin that is commonly used for the treatment for hyperkalemia. With the increasing prevalence of type II diabetes mellitus in developed nations, there has been a concordant rise in renal disease and hyperkalemic patients receiving Kayexalate therapy. Gastrointestinal necrosis is a rare but major complication associated with Kayexalate use that has not been previously well characterized in the forensic literature. Kayexalate crystals have a distinctive “mosaic” appearance on hematoxylin and eosin stained sections and a characteristic coloration with periodic acid-Schiff (PAS) and acid-fast stains. As they are relatively easily identified in histologic sections, and may represent a primary or contributory cause of death, it is suggested that forensic pathologists become familiar with these features. We present two cases in which Kayexalate crystals were detected at autopsy. In one case, the crystals were located within the intestinal lumen and mucosa in areas of mucosal ulceration, while in the other, crystals were located on the intestinal serosal surface without apparent mucosal ulceration. We discuss how to interpret the significance of Kayexalate crystals, review prior literature on Kayexalate therapy-related gastrointestinal necrosis, and explain how to notify the Food and Drug Administration of an adverse Kayexalate reaction detected at autopsy.

Drug-induced injury in the gastrointestinal tract

Abnormalities of the gastrointestinal tract due to drug-induced injuries are common and often have important clinical consequences. Medications may cause damage by direct corrosive effects on mucosae or by alter processes, mucosal immunity, and local environmental conditions. The aim of this review is to guide practicing pathologists in the identification of drug-related injuries in gastrointestinal mucosal biopsies and resection specimens. Common causes of injury and their gross, endoscopic, and microscopic features are presented.

Fabrication and evaluation of cationic exchange nanofibers for controlled drug delivery systems

The number of ion exchange fibers in development has increased over the last several years. However, few studies have reported the use ion-exchange fibers in drug delivery system. In this study polystyrene nanofiber ion exchangers (PSNIE) were fabricated by electrospinning techniques, crosslinking and sulfonation. The degree of crosslinking and the ion exchange capacity (IEC) were determined. The morphology and diameter of the nanofiber mats were analyzed using scanning electron microscopy (SEM). Five cationic model drugs (dextromethorphan, chlorpheniramine, diphenhydramine, propranolol and salbutamol) were loaded into PSNIE. The loading capacity, release and release kinetics of the exchangers were investigated. PSNIE were successfully prepared by electrospinning and were allowed to crosslink for 10 min, resulting in a maximum IEC of 2.86±0.1 meq/g dry PSNIE. The diameter of the fibers after sulfonation was 464±35 nm. Dextromethorphan provided the highest loading in PSNIE while diphenhydramine gave the highest percentage release in both simulated gastric and intestinal fluid (SGF and SIF). The release kinetics of all drugs in SGF and SIF provided the best fit with the particle diffusion model. Our results showed that the development of a PSNIE-based drug delivery system was successful, and PSNIE were able to control drug release.

Gastrointestinal adverse events with sodium polystyrene sulfonate (Kayexalate) use: a systematic review

BACKGROUND

Sodium polystyrene sulfonate (Kayexalate; Sanofi-Aventis, Paris, France) is a cation-exchange resin routinely used in the management of hyperkalemia. However, its use has been associated with colonic necrosis and other fatal gastrointestinal adverse events. Although the addition of sorbitol to sodium polystyrene sulfonate preparations was previously believed to be the cause of gastrointestinal injury, recent reports have suggested that sodium polystyrene sulfonate itself may be toxic. Our objective was to systematically review case reports of adverse gastrointestinal events associated with sodium polystyrene sulfonate use.

METHODS

MEDLINE (1948 to July 2011), EMBASE (1980 to July 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (1993 to July 27, 2011), bibliographies of identified articles, and websites of relevant drug agencies and professional associations in the United States and Canada were reviewed to identify eligible reports of adverse gastrointestinal events associated with sodium polystyrene sulfonate use. Causality criteria of the World Health Organization causality assessment system were applied to each report.

RESULTS

Thirty reports describing 58 cases (41 preparations containing sorbitol and 17 preparations without sorbitol) of adverse events were identified. The colon was the most common site of injury (n=44; 76%), and transmural necrosis (n=36; 62%) was the most common histopathologic lesion reported. Mortality was reported in 33% of these cases due to gastrointestinal injury.

CONCLUSIONS

Sodium polystyrene sulfonate use, both with and without sorbitol, may be associated with fatal gastrointestinal injury. Physicians must be cognizant of the risk of these adverse events when prescribing this therapy for the management of hyperkalemia.

To bind or to let loose: effectiveness of sodium polystyrene sulfonate in decreasing serum potassium

Background. The use of sodium polystyrene sulfonate in decreasing serum potassium has recently been questioned due to the lack of documented effectiveness. Methods. A retrospective cohort analysis of all hospitalized patients who received sodium polystyrene sulfonate over four months was performed. The change in serum potassium was noted over a period of 24 hours. Patients who received any other form of potassium-altering drug or treatment were excluded. Results. The administration of sodium polystyrene sulfonate reduced serum potassium by 16.7% (P < 0.001) as compared to the baseline serum potassium over a period of 24 hours. During this same time, no change in serum creatinine was identified (P = 0.73). In addition, there was no correlation between potassium and creatinine change (r(2) = 0.0004 and P = 0.99). Patients with higher initial serum potassium (≥5.6 mEq/L) reduced their potassium concentration 4% more than those with initial serum potassium of <5.6 mEq/L; however, this reduction did not reach statistical significance (P = 0.32). There was no significant difference in the effectiveness of 15 gm and 30 gm resin preparation (P = 0.54). Thirteen deaths were noted in our cohort, of which one death was due to ischemic colitis. Conclusion. We conclude that sodium polystyrene sulfonate is effective in lowering serum potassium.

The clinical management of tumour lysis syndrome in haematological malignancies

Tumour lysis syndrome (TLS) is caused by the disintegration of malignant cells, usually following the instigation of chemotherapy, although it may already be established at the time of initial presentation in a minority of cases. As a direct consequence of malignant cell breakdown, intracellular ions, proteins, nucleic acids and their metabolites are released into the plasma causing the characteristic metabolic abnormalities of TLS; hyperuricaemia, hyperkalaemia, hyperphosphataemia and hypocalcaemia. In many cases the release of large amounts intracellular contents is so abrupt that the normal homeostatic mechanisms are rapidly overwhelmed and without prompt, effective management, the clinical effects of TLS soon become apparent.

[Calcium polystyrene sulfonate induced colonic necrosis in patient with chronic kidney disease]

A 63-year-old woman was admitted due to right upper quadrant abdominal pain. She was going through hemodialysis due to end stage renal disease and taking calcium polystyrene sulfonate orally and rectally due to hyperkalemia. Colonoscopy showed a circular ulcerative mass on the proximal ascending colon. Biopsy specimen from the mass showed inflammation and necrotic debris. It also revealed basophilic angulated crystals which were adherent to the ulcer bed and normal mucosa. These crystals were morphologically consistent with calcium polystyrene sulfonate. She was diagnosed with calcium polystyrene phosphate induced colonic necrosis and improved with conservative treatment.

Colonic mucosal necrosis following administration of calcium polystryrene sulfonate (Kalimate) in a uremic patient

Colonic necrosis is known as a rare complication following the administration of Kayexalate (sodium polystryrene sulfonate) in sorbitol. We report a rare case of colonic mucosal necrosis following Kalimate (calcium polystryrene sulfonate), an analogue of Kayexalate without sorbitol in a 34-yr-old man. He had a history of hypertension and uremia. During the management of intracranial hemorrhage, hyperkalemia developed. Kalimate was administered orally and as an enema suspended in 20% dextrose water to treat hyperkalemia. Two days after administration of Kalimate enema, he had profuse hematochezia, and a sigmoidoscopy showed diffuse colonic mucosal necrosis in the rectum and sigmoid colon. Microscopic examination of random colonic biopsies by two consecutive sigmoidoscopies revealed angulated crystals with a characteristic crystalline mosaic pattern on the ulcerated mucosa, which were consistent with Kayexalate crystals. Hematochezia subsided with conservative treatment after a discontinuance of Kalimate administration.

Intestinal necrosis due to sodium polystyrene sulfonate (Kayexalate) in sorbitol

BACKGROUND

Sodium polystyrene sulfonate (SPS, Kayexalate) has been implicated in the development of intestinal necrosis. Sorbitol, added as a cathartic agent, may be primarily responsible. Previous studies have documented bowel necrosis primarily in postoperative, dialysis, and transplant patients. We sought to identify additional clinical characteristics among patients with probable SPS-induced intestinal necrosis.

METHODS

Rhode Island Hospital surgical pathology records were reviewed to identify all gastrointestinal specimens reported as containing SPS crystals from December 1998 to June 2007. Patient demographics, medical comorbidities, and hospital courses of histologically verified cases of intestinal necrosis were extracted from the medical records.

RESULTS

Twenty-nine patients with reports of SPS crystals were identified. Nine cases were excluded as incidental findings with normal mucosa. Nine patients were excluded as their symptoms began before SPS administration or because an alternate etiology for bowel ischemia was identified. Eleven patients had confirmed intestinal necrosis and a temporal relationship with SPS administration suggestive of SPS-induced necrosis. Only 2 patients were postoperative, and only 4 had end-stage renal disease (ESRD). All patients had documented hyperkalemia, received oral SPS, and developed symptoms of intestinal injury between 3 hours and 11 days after SPS administration. Four patients died.

CONCLUSION

Intestinal ischemia is a recognized risk of SPS in sorbitol. Our series highlights that patients may be susceptible even in the absence of ESRD, surgical intervention, or significant comorbidity.

Sodium polystyrene sulfonate (Kayexalate) aspiration

In this short report we illustrate a case of extensive sodium polystyrene sulfonate (SPS) aspiration as an immediate cause of death in a terminally ill patient. SPS is a cation exchange resin utilized to decrease potassium levels in patients with renal failure. When administered rectally in conjunction with sorbitol, colonic necrosis and perforation have been documented. On the other hand, oral administration can be complicated by aspiration, especially in very ill or debilitated patients. In our current report, histological examination of a patient who aspirated SPS shows multiple polygonal to amorphous basophilic crystalline particles deposited intraalveolarly. The purpose of our report is to familiarize pathologists with the histologic features of this rare iatrogenic complication of therapy for hyperkalemia.

Successful treatment of a colonic ulcer penetrating the urinary bladder caused by the administration of calcium polystyrene sulfonate and sorbitol

A 77-year-old woman was urgently admitted for the treatment of diabetic ketoacidosis and a duodenal ulcer hemorrhage in March 1999. She had a history of diabetes and angina pectoris. After admission, she received oral calcium polystyrene sulfonate and sorbitol to treat hyperkalemia. Nine days later, severe abdominal pain developed. A colonoscopic examination revealed a sigmoid colonic ulcer and stenosis; the patient was treated conservatively. At a 1-year follow-up examination, the colonic stenosis was found have worsened; pneumaturia developed in January 2001. The patient was found to have a sigmoidovesical fistula and underwent sigmoidectomy and partial resection of the ileum and urinary bladder. The histological findings were a benign colonic ulcer with the infiltration of inflammatory cells, mainly lymphocytes. Rhomboidal, dark violet Kayexalate crystals were observed on microscope examination in the submucosa in both the first and second colonic biopsy specimens. We concluded that the colonic ulcer and the sigmoidovesical fistula had been caused by the administration of calcium polystyrene sulfonate and sorbitol. Reports of colonic perforation as a result of the administration of calcium polystyrene sulfonate and sorbitol are rare. Here, we report the successful treatment of a colonic ulcer that had penetrated the urinary bladder.

Rectal stenosis caused by foreign body reaction to sodium polystyrene sulfonate crystals (Kayexalate)

Sodium polystyrene sulfonate (SPS) (Kayexalate) is a cation-exchange resin used to treat hyperkaliema. Administered with sorbitol, it usually has minor adverse effects, but it may cause colonic or intestinal necrosis in uremic patients. We report an unusual case of rectal stenosis due to SPS crystals in a 46-year-old man. The patient had been involved in a car accident with severe thoracic and abdominal trauma. During his hospitalization, he presented traumatic acute pancreatitis with ischemic colitis because of hypotension, and acute renal insufficiency treated by hemofiltration and Kayexalate administered by nasogastric tube without sorbitol. Left colon was resected and Hartmann's procedure was performed. Restoration of the colon continuity was performed 13 months later. The rectal lumen was narrowed with a thickened rectal wall. Microscopic examination revealed fibrosis of the submucosa containing numerous basophilic polygonal crystals surrounded by macrophages. This is the first case report of rectal stenosis caused by foreign body reaction to SPS crystals after ischemic colitis.

The management of tumor lysis syndrome

The manifestation of tumor lysis syndrome (TLS) occurs when the destruction of tumor cells releases breakdown products that overwhelm the excretory mechanisms of the body. A cardinal sign is hyperuricemia, leading to uric acid nephropathy. Other signs are hyperkalemia, hyperphosphatemia and secondary hypocalcemia. Conventional management of TLS consists of aggressive intravenous hydration, diuretic therapy, urinary alkalization, and inhibition of urate production by high-dose allopurinol. Urate oxidase has been used in the management of patients at risk for TLS and recently the recombinant urate oxidase rasburicase was developed. Several data indicate that rasburicase is effective and well tolerated in the prevention and treatment of chemotherapy-induced hyperuricemia. Treatment options of hyperkalemia include sodium polystyrene sulfonate, hypertonic glucose and insulin, loop diuretics, and bicarbonate. Treatment of hyperphosphatemia reduces dietary phosphate intake and includes phosphate binders such as aluminum hydroxide and aluminum carbonate. When recurrent hypocalcemia is present, a continuous intravenous infusion of calcium gluconate can be initiated. Hemodialysis should be considered for every patient with excessively elevated uric acid, phosphate and/or potassium and in those patients with acute renal failure to control urinary volume and manage uremia.

Gastrointestinal complications following transplantation

Gastrointestinal complications are common after kidney, liver, pancreas, heart, and lung transplantation. Complications can include gastrointestinal conditions preceding the transplantation, viral, fungal, and bacterial gastrointestinal infections, and gastrointestinal side effects of medications including immunosuppressive agents. Establishing the etiology of gastrointestinal complaints is often difficult because any one or a combination of these factors might be contributory in the same patient.

A Randomized Controlled Trial of Fludrocortisone for the Treatment of Hyperkalemia in Hemodialysis Patients

BACKGROUND

Previous small uncontrolled studies suggested that fludrocortisone may significantly decrease serum potassium concentrations in hemodialysis patients, possibly through enhancement of colonic potassium secretion. The aim of this study is to evaluate the effect of oral fludrocortisone on serum potassium concentrations in hyperkalemic hemodialysis patients in an open-label randomized controlled trial.

METHODS

Thirty-seven hemodialysis patients with predialysis hyperkalemia were randomly allocated to administration of either oral fludrocortisone (0.1 mg/d; n = 18) or no treatment (control; n = 19) for 3 months. The primary outcome measure was midweek predialysis serum potassium concentration, which was measured monthly during the trial. Prospective power calculations indicated that the study had an 80% probability of detecting a decrease in serum potassium levels of 0.7 mEq/L (0.7 mmol/L).

RESULTS

Baseline patient characteristics were similar, except for slightly longer total weekly dialysis hours in the fludrocortisone group (13.0 +/- 1.3 versus 12.1 +/- 1.0; P = 0.02). At the end of the study period, no significant changes in serum potassium concentrations were observed between the fludrocortisone and control groups (4.8 +/- 0.5 versus 5.2 +/- 0.7 mEq/L [mmol/L], respectively; P = 0.10). Similar results were obtained when changes in serum potassium levels over time were examined between the 2 arms by using repeated-measures analysis of variance, with or without adjustment for total weekly dialysis hours. Secondary outcomes, including predialysis mean arterial pressure, interdialytic weight gain, serum sodium level, and hospitalization for hyperkalemia, were not significantly different between groups. There were no observed adverse events.

CONCLUSION

Administering fludrocortisone to hyperkalemic hemodialysis patients is safe and well tolerated, but does not achieve clinically important decreases in serum potassium levels.

Hyperkalemia in dialysis patients

Serious hyperkalemia is common in patients with end-stage renal disease (ESRD) and accounts for considerable morbidity and death. Mechanisms of extrarenal disposal of potassium (gastrointestinal excretion and cellular uptake) play a crucial role in the defense against hyperkalemia in this population. In this article we review extrarenal potassium homeostasis and its alteration in patients with ESRD. We pay particular attention to the factors that influence the movement of potassium across cell membranes. With that background we discuss the emergency treatment of hyperkalemia in patients with ESRD. We conclude with a review of strategies to reduce the risk of hyperkalemia in this population of patients.

Upper gastrointestinal tract injury in patients receiving kayexalate (sodium polystyrene sulfonate) in sorbitol: clinical, endoscopic, and histopathologic findings

Kayexalate (sodium polystyrene sulfonate) in sorbitol has been demonstrated to cause colonic necrosis in a subset of uremic patients who are administered the cation exchange resin for treatment of hyperkalemia. Upper gastrointestinal damage associated with Kayexalate in sorbitol is reported far less frequently, and the clinicopathologic spectrum of disease in cases with upper gastrointestinal damage has not been investigated previously. The authors studied the clinical, endoscopic, and histologic features of 11 patients with Kayexalate crystals in biopsies from the esophagus (n = 7), stomach (n = 6), and duodenum (n = 2). The endoscopic appearance was markedly abnormal in all 11 patients. The effects of the medication closely mimicked other endoscopic and radiologic diagnoses in three cases, including esophageal carcinoma, Candidal esophagitis, and gastric bezoar. Histologic and/or endoscopic evidence of mucosal injury in the form of an ulcer or erosion was present in nine patients (82%). In four patients with mucosal injury, no other etiology apart from Kayexalate in sorbitol could be identified. In comparison with a cohort of patients with Kayexalate crystals in lower gastrointestinal specimens identified during the same period (11 patients) the frequency of associated mucosal damage was not significantly different (55%, p = 0.19), but no patient with upper gastrointestinal Kayexalate required surgical resection or died as a result of Kayexalate-induced mucosal injury. The results of this study provide evidence that Kayexalate in sorbitol can induce damage to the upper gastrointestinal tract. Recognition of Kayexalate crystals in histologic sections as a marker for sorbitol-induced mucosal damage may aid in establishing the correct diagnosis for clinically or endoscopically misleading lesions.

Acute renal failure: a practical update

Acute renal failure (ARF) affects almost all medical specialties. Its occurrence seems to be increasing in hospitalized patients. A structured approach to the evaluation and management of ARF would facilitate rapid diagnosis and treatment in most patients. Appreciation for the multiple drugs that affect renal function is especially important. Exclusion of urinary outflow obstruction and administration of therapies that improve renal perfusion should be given top priority with respect to managing ARF. Dialytic intervention for ARF is required when otherwise irreversible pathophysiologic derangements of electrolyte homeostasis, fluid balance, and uremic solute control are imminent. This article provides a brief review and update on the clinical evaluation and management of ARF.

The use of histological techniques for the demonstration of ion exchange resins

AIM

To establish the staining characteristics of certain ion exchange resins in histological material, with a view to enabling confident differential identification.

METHODS

Various histological staining procedures were applied to selected pathological material and prepared agar blocks containing the cation exchange resin calcium polystyrene sulphonate and the anion exchange resin cholestyramine.

RESULTS

Calcium polystyrene sulphonate uniquely stained strongly by a direct Schiff's reagent procedure without any preoxidation and by the Ziehl-Neelsen method. Cholestyramine was negative by the former method but stained strongly with a standard Congo red technique.

CONCLUSIONS

These staining results are consistent with the known structure and properties of polystyrene sulphonate and cholestyramine resins. Polystyrene sulphonate resins have the virtually pathognomonic feature of direct Schiff positivity, while morphology, location, and strong non-birefringent Congo red positivity facilitate the identification of cholestyramine. It is possible that the intrinsic staining characteristics of cholestyramine may be lost once it has bound to its target.

Combined gastric and ileocecal toxicity (serpiginous ulcers) after oral kayexalate in sorbital therapy

Kayexalate (Roxane Labs, Columbus, OH) in sorbitol is commonly administered by the oral and rectal route for the treatment of hyperkalemia in patients with renal failure. It is believed to have minimal toxicity because it functions as a cation exchanger and is not absorbed. We herein report on a patient who developed identical serpiginous ulcers in the stomach and the terminal ileum after the use of Kayexalate. We believe that this drug could have significant gastrointestinal toxicity in specific patient groups and suggest tentative guidelines, both for the identification of such patients and for the safer use of Kayexalate in these circumstances.

Necrosis of the gastrointestinal tract in uremic patients as a result of sodium polystyrene sulfonate (Kayexalate) in sorbitol: an underrecognized condition

Sodium polystyrene sulfonate (Kayexalate) in sorbitol given as an enema or orally to treat hyperkalemia has been reported to induce intestinal necrosis in uremic patients. We studied the clinical and pathologic features of 15 patients in whom Kayexalate crystals were observed in specimens from gastrointestinal surgical resections (n = 9) or endoscopic biopsies (n = 7). Oral or nasogastric tube administration of Kayexalate in sorbitol was documented in 10 patients. Among 12 patients with colorectal specimens, necrosis was observed in nine patients (75%), represented by seven of eight surgical resection specimens and three of five endoscopic biopsy specimens. No other cause of colorectal necrosis apart from Kayexalate in sorbitol was apparent in seven patients, and four also had necrosis of the small intestine. Four patients with colonic necrosis in their initial resection specimen developed progressive necrosis of the small intestine or rectum, and five patients (56%) had fatal outcome within 1 day to 6 weeks. Kayexalate crystals were observed in upper gastrointestinal tract specimens from four patients, including one with hemorrhagic gastritis. Our findings provide additional evidence that Kayexalate in sorbitol administered orally or by nasogastric tube can produce necrosis in the gastrointestinal tract.