Use of Fludrocortisone for Hyperkalemia in Chronic Kidney Disease Not Yet on Dialysis.

Background: Hyperkalemia is a frequent and potentially lethal complication of chronic kidney disease (CKD). We retrospectively examined the potassium-lowering effect of oral fludrocortisone and its adverse effects in hyperkalemic CKD patients not yet on dialysis. Methods: Thirty-three patients (23 men and 10 women, ages 69±14 years) were included. To control hyperkalemia at the outpatient clinic, twenty-one patients (Group 1) received fludrocortisone (0.05-0.1 mg/day) without changes in angiotensin II receptor blockers (ARBs) and calcium polystyrene sulfonate (CPS), while twelve patients (Group 2) were treated with fludrocortisone in addition to stopping ARBs and/or adding low-dose CPS. Results: Fludrocortisone was administered for a median of 169 days (interquartile range, 47-445). At the first follow-up after fludrocortisone administration, serum potassium dropped from 6.14±0.32 mEq/L to 4.52±1.06 mEq/L (p<0.001) in Group 1 and from 6.37±0.35 mEq/L to 4.08±0.74 mEq/L (p<0.01) in Group 2. Ten patients in Group 1 and five patients in Group 2 measured serum potassium levels at four outpatient visits before and after fludrocortisone administration, respectively. The frequency of serum potassium ≥6.0 mEq/L decreased from 19/40 (48%) to 2/40 (5%) (p<0.001) in Group 1 and from 11/20 (55%) to 0/20 (0%) (p<0.001) in Group 2. Eleven patients experienced sodium retention-related problems after fludrocortisone administration: 7 with worsening leg edema, 2 with pleural effusions, and 2 with pulmonary edema. Conclusion: In pre-dialysis CKD patients, fludrocortisone at low doses effectively reduced serum potassium levels; however, sodium retention was a common adverse effect.

Calcium polystyrene sulfonate-induced rectal ulcer causing E. coli native-valve infective endocarditis.

Escherichia coli-associated native-valve infective endocarditis is a rare disease that affects elderly patients with underlying risk factors such as diabetes mellitus, malignancy, and renal failure. Long-term use of calcium polystyrene sulfonate is a potential risk factor for gastrointestinal mucosal damage or even colorectal ulcers. Herein, we describe a fatal case of a 66-year-old Japanese man with diabetes mellitus and renal failure who was prescribed calcium polystyrene sulfonate (CPS) for 11 years and developed a CPS-induced rectal ulcer, leading to E. coli native-valve infective endocarditis. The patient was admitted to our hospital due to acute-onset impaired consciousness. As a result of the systemic investigation, he was diagnosed with E. coli bacteremia accompanied by multiple cerebral infarctions and an acute hemorrhagic rectal ulcer. Transesophageal echocardiography revealed a 20-mm vegetative structure on the mitral valve, resulting in a final diagnosis of E. coli-associated infective endocarditis. After rectal resection, mitral valve replacement surgery was performed; however, the patient died shortly after surgery. Pathological findings of the resected rectum showed deposition of a basophilic crystalline material suggesting the presence of CPS. Our case highlights the potential risk of colorectal ulcers in a long-term CPS user, which can trigger bacterial translocation and endocarditis as fatal complications.

Calcium Polystyrene Sulfonate Crystal-related Airway Obstruction.

An 83-year-old man diagnosed with multiple myeloma presented with renal failure and hyperkalemia. The patient was treated with calcium polystyrene sulfonate (CPS; kalimate) for hyperkalemia. On the 10th day after starting CPS, airway obstruction due to the presence of a mass was observed, and the patient died on that same day. Autopsy revealed that the mass was located between the trachea and epiglottis and it was determined to consist of CPS-related mosaic crystals. There was a protrusion within the trachea surrounding the CPS crystals, inflammatory cells, and granulation tissue. This case suggests that CPS is associated with not only gastrointestinal complications, but also with airway complications.

In vitro and in vivo removal efficacy of insoluble Prussian blue in combination with calcium polystyrene sulfonate for thallium.

The similarities between thallium and potassium have suggested the use of calcium polystyrene sulfonate (CPS), an oral ion exchange resin, as a potential agent against thallium intoxication. Therefore, the study was an attempt to evaluate the efficacy of CPS and Prussian blue when given alone or in combination against thallium toxicity. The effect on binding capacity was investigated in terms of contact time, amount of CPS, influence of pH, simulated physiological solutions and interference of potassium ions. Also, rats were given single dose of thallium chloride (20 mg kg-1) and the treatment with PB and CPS was given for 28 days as CPS 30 g kg-1, orally, twice a day, PB 3 g kg-1, orally, twice a day and their combination. The effect of antidotal treatment was evaluated by calculating the thallium levels in various organs, blood, urine and feces. The results of the in vitro study indicated exceedingly quick binding in the combination of CPS and PB as compared to PB alone. Also, it was found that the binding capacity at pH 2.0 was considerably increased for PB with CPS (184.656 mg g-1) as compared to PB (37.771 mg g-1). Furthermore, statistically significant results were obtained in the in vivo study as after 7th day, thallium levels in blood of rats treated with combination were reduced by 64% as compared to control group and 52% as compared to alone PB treated group. Also, Tl retention in liver, kidney, stomach, colon and small intestine of combination treated rats was significantly reduced to 46%, 28%, 41%, 32% and 33% respectively, as compared to alone PB treated group. These findings demonstrate this as a good antidotal option against thallium intoxication.

Efficacy and safety of calcium polystyrene sulfonate in patients with hyperkalemia and stage 3-5 non-dialysis chronic kidney disease: a single-center randomized controlled trial.

OBJECTIVE: To observe the clinical efficacy and safety of the short-term administration of different doses of calcium polystyrene sulfonate in the treatment of hyperkalemia in patients with stage 3-5 non-dialysis chronic kidney disease. METHODS: A prospective, open, randomized, controlled, single-center clinical observation was conducted. In total, 107 patients were randomly assigned to receive calcium polystyrene sulfonate at 15 (group A) or 30 mg/day (group B) for 1 week. Patients were assessed on days 0, 3, and 7. RESULTS: After 3 days of treatment, the serum potassium levels in groups A and B had decreased by 0.68 ± 0.46 and 0.75 ± 0.43 mmol/L, respectively. After 7 days, the serum potassium levels in groups A and B had decreased by 0.64 ± 0.37 and 0.94 ± 0.49 mmol/L, respectively. Conversely, serum sodium, phosphorus, and calcium levels did not significantly change during the treatment period. Constipation was the most common adverse drug reaction, and no treatment-related serious adverse events were observed. CONCLUSION: Calcium polystyrene sulfonate administered at a dose of 15 or 30 g/day can rapidly reduce potassium levels in patients with stage 3-5 non-dialysis chronic kidney disease without adverse effects on sodium, phosphorus, or calcium levels.

Compared effectiveness of sodium zirconium cyclosilicate and calcium polystyrene sulfonate on hyperkalemia in patients with chronic kidney disease.

Hyperkalemia is a well-recognized electrolyte abnormality in patients with chronic kidney disease (CKD). Potassium binders are often used to prevent and treat hyperkalemia. However, few studies have evaluated the difference in serum potassium (K+) level-lowering effect during the post-acute phase between the novel potassium binder, sodium zirconium cyclosilicate (ZSC), and conventional agents. This retrospective study included patients who received potassium binders (either ZSC or calcium polystyrene sulfonate [CPS]) in our hospital between May 2020 and July 2022. The patients were divided into the ZSC and CPS groups. After propensity score matching, we compared changes from baseline to the first follow-up point, at least 4 weeks after initiating potassium binders, in electrolytes including K+ level between the two groups. Of the 132 patients, ZSC and CPS were administered in 48 and 84 patients, respectively. After matching, 38 patients were allocated to each group. The ZSC group showed greater reduction in K+ levels than did the CPS group (P < 0.05). Moreover, a significant increase in serum sodium minus chloride levels, a surrogate marker for metabolic acidosis, was observed in the ZSC group (P < 0.05). Our results demonstrated that ZSC could potentially improve hyperkalemia and metabolic acidosis in patients with CKD.

Prescription Pattern of Cation Exchange Resins and Their Efficacy in Treating Chronic Hyperkalemia Among Patients With Chronic Kidney Diseases: Findings From a Population-Based Analysis in British Columbia, Canada.

Background: Little was known about how chronic hyperkalemia (cHK) in patients with chronic kidney disease (CKD) is managed in British Columbia, Canada. Objective: To investigate the trend in sodium polystyrene sulfonate (SPS) and calcium polystyrene sulfonate (CPS) utilization and their efficacy in treating cHK in CKD patients from British Columbia, Canada. Study Design: Retrospective cohort. Setting & Patients: CKD patients aged ≥18 years, followed in Kidney Care Clinic (KCC), who had at least 2 potassium values ≥5.0 mmol/L separated by no more than 91 days during the period of June 1, 2015, to July 31, 2021, were included. Index date was the first date of the 2 potassium values ≥5.0 mmol/L. Patients who received SPS or CPS within 90 days before index date were excluded. Patients who were on dialysis or received kidney transplantation on or before index date were also excluded. Exposure: Continuous exposure to SPS and CPS. Outcome: SPS/CPS prescription utilization trend was described by the proportion of patients ever treated with SPS/CPS, median time in days between cHK diagnosis and initiating treatment with SPS/CPS, total and median number of SPS/CPS prescriptions dispensed. Change in mean serum potassium concentration before and after a 90-day continuous treatment with SPS/CPS was estimated. Analytical Approach: Descriptive. Results: This study included 10 495 patients with cHK (median age 74 years, 60% were male). Median follow-up time was 625 days. Only 2864 (27%) patients were dispensed at least 1 prescription of either SPS or CPS. A total 7300 prescriptions were dispensed; median prescriptions dispensed per patients were 2 (interquartile range [IQR]: 1-3). Median time from index date to the first prescription dispensing date was 154 days (IQR: 36-455). Continuous 90-day treatment with SPS/CPS decreased the mean serum potassium concentration by 0.60 mmol/L, from 5.58 to 4.98 mmol/L. Limitations: Descriptive observational study without control group. Conclusions: In British Columbia, only 1 in 4 CKD patients with cHK were dispensed with SPS/CPS, mostly with higher degrees of hyperkalemia. These medications appeared to be moderately effective in reducing the serum potassium concentration. Future research is necessary to evaluate the comparative effectiveness of newer generation medications.

Contexte: On savait peu de choses sur la façon dont l'hyperkaliémie chronique (HKc) est prise en charge chez les patients atteints d'insuffisance rénale chronique (IRC) de la Colombie-Britannique (C.-B.), au Canada. Objectif: Étudier les tendances d'utilisation du sulfonate de polystyrène sodique (SPS) et du sulfonate de polystyrène calcique (SPC), ainsi que l'efficacité de ces agents dans le traitement de l'HKc chez les patients britanno-colombiens atteints d'IRC. Type d'étude: étude de cohorte rétrospective. Sujets et cadre de l'étude: Ont été inclus des adultes atteints d'IRC suivis en clinique de soins rénaux qui avaient au moins 2 valeurs de potassium ≥ 5,0 mmol/L mesurées à moins de 91 jours d'intervalle entre le 1er juin 2015 et le 31 juillet 2021. La date de la première des deux valeurs de potassium ≥ 5,0 mmol/L constitue la date indice. Les patients qui avaient reçu du SPS ou du SPC dans les 90 jours précédant la date indice ont été exclus. Les patients sous dialyse ou ayant reçu une greffe rénale avant ou à la date indice ont également été exclus. Exposition: Exposition continue au SPS et au SPC. Résultats: La tendance d'utilisation de SPS/SPC a été décrite par la proportion de patients ayant déjà été traités par SPS/SPC, par le temps médian en jours entre le diagnostic d'hyperkaliémie chronique et le début du traitement par SPS/SPC, et par le nombre total et médian de prescriptions de SPS/SPC délivrées. La variation de la concentration moyenne de potassium sérique avant et après un traitement continu de 90 jours avec SPS/SPC a été estimée. Approche analytique: Descriptive. Résultats: L'étude porte sur 10 495 patients atteints d'hyperkaliémie chronique (60 % d'hommes; âge médian: 74 ans). Le temps médian de suivi était de 625 jours. Seulement 2 864 (27 %) patients avaient reçu au moins une prescription de SPS ou de SPC. Au total, 7 300 ordonnances ont été délivrées; la moyenne d'ordonnances délivrées par patient était de 2 (IIQ: 1, 3). Le délai médian entre la date indice et la date de la première ordonnance était de 154 jours (IIQ: 36, 455). Un traitement continu de 90 jours avec SPS/SPC a abaissé la concentration moyenne de potassium sérique de 0,60 mmol/L, la faisant passer de 5,58 à 4,98 mmol/L. Limites: Étude observationnelle descriptive sans groupe témoin. Conclusion: En C.-B., seul un patient sur quatre atteint d'IRC avec HKc avait reçu une prescription de SPS/SPC, la plupart présentaient des degrés plus élevés d'hyperkaliémie. Ces médicaments se sont avérés modérément efficaces pour réduire la concentration sérique en potassium. Des recherches supplémentaires sont nécessaires pour évaluer l'efficacité comparative des médicaments de nouvelle génération.

Hyperkalaemia and potassium binders: Retrospective observational analysis looking at the efficacy and cost effectiveness of calcium polystyrene sulfonate and sodium zirconium cyclosilicate.

WHAT IS KNOWN AND OBJECTIVE: Hyperkalaemia is a common medical emergency in patients admitted to hospital. There is a limited evidence base supporting some of the commonly applied treatment strategies. Although, NICE has recommended the use of sodium zirconium cyclosilicate (SZC) (TA599) and patiromer (TA623) in both acute and chronic hyperkalaemia, there is a limited evidence base for their use in acute hyperkalaemia in the hospital setting, particularly when compared to the present standard of care calcium polystyrene sulfonate (CPS). METHODS: A retrospective review of the electronic patient record system across our hospital over a 6-month period identified 138 patients who received either SZC (65 patients) or CPS (73 patients) to manage hyperkalaemia, investigating their efficacy and cost effectiveness. Results were analysed using simple descriptive statistics. Based on the results a naïve cost comparison between the two drugs was made. RESULTS AND DISCUSSION: CPS and SZC both effectively reduced plasm potassium concentrations in patients with hyperkalaemia (6.07 and 6.03 mmol/L respectively) by 1.17 mmol/L and 1.24 mmol/L taking a similar amount of time to work (2.97 days vs. 3 days). The principle causes of hyperkalaemia identified were acute kidney injury, medication, and chronic kidney disease. Cost comparison analysis which took into account raw product price and time needed to dispense medications revealed that CPS has slightly better cost effectiveness compared to SZC albeit at a cost of increased staff input. WHAT IS NEW AND CONCLUSION: Both CPS and SZC were equally effective at lowering acutely raised potassium concentrations. The cost difference between the two products appears to be small. Claims regarding the benefits of newer agents over older established medications need to be properly explored in randomized trials rather than being based on small scale non-comparative studies.

Efficacy and safety of potassium binders in the treatment of patients with chronic kidney disease and hyperkalemia.

BACKGROUND: Gastrointestinal cation exchangers that can bind potassium in the gut, including sodium polystyrene sulfonate (SPS), calcium polystyrene sulfonate (CPS), patiromer and sodium zirconium cyclosilicate (SZC), are emerging medications for the treatment of hyperkalemia with chronic kidney disease (CKD). However, which might be the best alternative for patients with chronic kidney disease and hyperkalemia remains disputed. METHODS: We performed this systematic review and network meta-analysis with the Bayesian approach to conduct direct and indirect comparisons among potassium binders regarding their efficacy and safety. The surface under the cumulative ranking curve analysis (SUCRA) was used to calculate the best intervention for each outcome. RESULTS: All four potassium binders had a promising effect regarding potassium reduction. SPS had favorable efficacy and safety for short-term use (MD: -0.94; 95% CIs: -1.4 to -0.48; SUCRA = 94.69%), but long-term treatment required strict dose control and assessment of gastrointestinal conditions. CPS had a positive effect on reducing potassium, and could especially maintain the serum potassium concentration in patients receiving renin-angiotensin-aldosterone system inhibitors (RAASi). Patiromer might reduce all-cause mortality in CKD patients with hyperkalemia and have a positive effect on potassium-lowering, though it had significant gastrointestinal adverse effects. SZC had a potassium-lowering effect in both the short-term and long-term, and can be a promising long-term treatment for the hyperkalemia in CKD patients, especially in combination with RAASi. CONCLUSION: These four potassium binders had their own advantages and disadvantages, and the medication should be selected according to the clinical situation of the patient.

Calcium polystyrene sulfonate associated colonic mucosal injury-innocent bystander or pathogenic culprit?: a case report and literature review.

Colonic mucosal injury is rare, but may severely fatal, complications following the administration of calcium polystyrene sulfonate resins. The incidence rate is about 0.57%, administered without sorbitol, and increases to 1.8% when it is concomitant with sorbitol, especially in postoperative patients. In this case report, we demonstrated the case of a 77-year-old female with stage 3b chronic kidney disease presented with in-hospital hematochezia after 3 weeks of calcium polystyrene sulfonate administration. The colonoscopic findings showed several serpiginous ulcers with some oozing at descending and sigmoid colon. The histological findings revealed some focal inflammation and ulcerations with crystal-like materials, compatible with cation exchange resins. The recent in vitro study, explaining the pathogenesis of cation exchange resin-associated colonic mucosal injury, was also reviewed.

Comparative Study of Constipation Exacerbation by Potassium Binders Using a Loperamide-Induced Constipation Model.

Patients on dialysis are frequently administered high doses of potassium binders such as calcium polystyrene sulfonate (CPS) and sodium polystyrene sulfonate (SPS), which exacerbate constipation. Here, we compare the degree of constipation induced by CPS and SPS using a loperamide-induced constipation model to identify the safer potassium binder. Constipation model was created by twice-daily intraperitoneal administration (ip) of loperamide hydrochloride (Lop; 1 mg/kg body weight) in rats for 3 days. Rats were assigned to a control group, Lop group, Lop + CPS group or Lop + SPS group, and a crossover comparative study was performed. Defecation status (number of feces, feces wet weight, fecal water content and gastrointestinal transit time (GTT)) was evaluated. In the Lop + CPS group, GTT was significantly longer, and fecal water content was reduced. In the Lop + SPS group-although the fecal water content and GTT were unaffected-the number of fecal pellets and the fecal wet weight improved. Thus, SPS was less likely to cause constipation exacerbation than CPS. Considering the high frequency of constipation in dialysis patients with hyperkalemia, preferentially administering SPS over CPS may prevent constipation exacerbation.

Intestinal necrosis related to administration of cation exchange resin without sorbitol: A retrospective analysis of 61 patients with end-stage renal diseases.

Intestinal necrosis associated with cation exchange resin (CER) is considered related to sorbitol, but it has been reported even in patients receiving CER alone. This study was performed to identify the risk factors of CER-related intestinal necrosis. The pathological database of 61 end-stage renal disease patients with surgical intervention for intestinal perforation was reviewed. The correlations between CER treatment and clinicopathological factors were studied among three groups: (i) patients administered CER and with CER at the perforation site (n = 23), (ii) patients administered CER with undetected CER at the perforation site (n = 12) and (iii) patients not administered CER (n = 26). The majority of the perforation site in group 1 was in the sigmoid colon (82.6%) with significantly higher average age and more frequent CER adhesion rates to the mucosa around the perforation site than group 2. The laxative administration rate in group 1 was significantly higher than group 3 and tended to be higher than group 2. The incidence of CER-related intestinal necrosis was estimated at 0.57%. CER should be used with extreme caution in elderly patients with passage disturbance.

Hyperkalemia in chronic kidney disease

SUMMARY Hyperkalemia is a frequent finding in patients with chronic kidney disease (CKD). This increase in serum potassium levels is associated with decreased renal ion excretion, as well as the use of medications to reduce the progression of CKD or to control associated diseases such as diabetes mellitus and heart failure. Hyperkalemia increases the risk of cardiac arrhythmia episodes and sudden death. Thus, the control of potassium elevation is essential for reducing the mortality rate in this population. Initially, the management of hyperkalemia includes orientation of low potassium diets and monitoring of patients' adherence to this procedure. It is also important to know the medications in use and the presence of comorbidities to guide dose reduction or even temporary withdrawal of any of the potassium retention-related drugs. And finally, the use of potassium binders is indicated in both acute episodes and chronic hyperkalemia.

RESUMO A hiperpotassemia é um achado frequente em pacientes com doença renal crônica (DRC). Esta elevação do nível sérico de potássio está associada à diminuição da excreção renal do íon, assim como ao uso de medicações para retardar a progressão da DRC ou para controlar doenças associadas, como diabetes mellitus e insuficiência cardíaca. A hiperpotassemia aumenta o risco de episódios de arritmia cardíaca e morte súbita. Assim, o controle da elevação de potássio é essencial para a diminuição da taxa de mortalidade nessa população. O manejo da hiperpotassemia inclui, inicialmente, orientação de dietas com baixo teor de potássio e acompanhamento da aderência dos pacientes a esse procedimento. Também é importante conhecer as medicações em uso e a presença de comorbidades, a fim de orientar a redução de doses ou até mesmo a suspensão temporária de alguma das drogas relacionadas à retenção de potássio. E, finalmente, o uso de quelantes de potássio é indicado tanto em episódios agudos como nos casos de hiperpotassemia crônica.

Pharmacologic Treatment of Chronic Hyperkalemia in Patients with Chronic Kidney Disease.

Hyperkalemia is frequently complicated in patients with advanced chronic kidney disease (CKD) because kidney is the major route of potassium excretion. Urinary potassium excretion is reduced according to the decline in glomerular filtration rate, and the risk of hyperkalemia is increased in patients with high potassium intake, advanced age, diabetes mellitus, congestive heart failure, and medications such as renin-angiotensin-aldosterone system(RAAS) blockades. On the other hand, the benefits of RAAS blockades and a high-potassium diet should be considered in CKD patients. To overcome these contradictory treatment strategies, potassium binders have emerged as new options to enhance fecal potassium excretion. In different regions of the world, four types of potassium binders are preferentially used. Whereas sodium polystyrene sulfonate (SPS) exchanges sodium for potassium, calcium polystyrene sulfonate (CPS) has the advantage of avoiding hypervolemia because it exchanges calcium for potassium. SPS was first introduced in the 1950s and used for a long time in western countries, and CPS is currently prescribed in Asia including South Korea. In contrast with the paucity of clinical studies using SPS or CPS, the recent randomized, controlled trials reported that two newer potassium binders, patiromer and sodium zirconium cyclosilicate (ZS-9), effectively and safely reduce serum potassium levels in CKD patients taking RAAS blockades. Our experiences showed that the long-term administration of a small dose of CPS was also effective and safe in treatment of chronic hyperkalemia. Further comparative trials among patiromer, ZS-9, and CPS are required to provide guides to cost-effective management of hyperkalemia in CKD patients.

Calcium-Polystyrene Sulfonate Decreases Inter-Dialytic Hyperkalemia in Patients Undergoing Maintenance Hemodialysis: A Prospective, Randomized, Crossover Study.

Hyperkalemia is a life-threatening emergency in maintenance hemodialysis (MHD) patients. This clinical trial investigated the efficacy and safety of calcium-polystyrene sulfonate (Ca-PS) in MHD patients with interdialytic hyperkalemia. A total of 58 hemodialysis patients with hyperkalemia (≥5.5 mol/L) were selected and administered either a 3-week Ca-PS (3 × 5 g/day) or a blank control following the model of a prospective, randomized, crossover clinical trial with a 1-week washout period. All patients were followed up for another 3 weeks for safety evaluations. The primary outcome was the magnitude of the change in serum potassium levels. The secondary outcomes were electrocardiography (ECG) changes and treatment safety (volume overload, electrolyte imbalance). Compared with the control group, Ca-PS treatment significantly reduced serum potassium levels (P <0.01). More patients in the Ca-PS group had lower serum potassium levels than the safety level of <5.5 mmol/L (32% for control vs. 61% for Ca-PS, P <0.01). Peaked T-wave occurred less frequently in patients in the Ca-PS group (13.8% for Ca-PS vs. 31.03% for control, P <0.01). In addition, Ca-PS reduced serum phosphorus levels with no effects on serum levels of calcium and sodium, fluid volume, blood pressure, or interdialytic weight gain. Ca-PS treatment decreases serum levels of potassium and phosphorus in MHD patients with interdialytic hyperkalemia. Ca-PS does not induce volume overload or disrupt electrolyte balance.

Hepatic portal venous gas due to polystyrene sulfonate-induced enteritis.

A 78-year-old man with acute right lower abdominal pain and nausea was referred to our hospital. Computed tomography (CT) demonstrated hepatic portal venous gas and a thickened wall of the terminal ileum, and colonoscopy demonstrated ulcers and erosions of the ileocecal region. Histological examination of biopsy samples revealed basophilic crystals consistent with the component of calcium polystyrene sulfonate (CPS). This patient started taking CPS 2 months prior for chronic hyperkalemia. The symptoms resolved soon after ceasing CPS, and subsequent imaging studies confirmed the disappearance of the portal venous gas and ileocolitis.

The chitosan-gelatin (bio)polyelectrolyte complexes formation in an acidic medium.

The interaction of cationic polysaccharide chitosan and gelatin accompanied by the stoichiometric (bio)polyelectrolyte complexes formation has been studied by the methods of capillary viscometry, UV and FTIR spectroscopy and dispersion of light scattering. Complexes were formed in the aqueous phase, with pH being less than the isoelectric point of gelatin (pIgel). The particle size of the disperse phase increases along with the growth of the relative viscosity in comparison with sols of the individual components-polysaccharide and gelatin. Possible models and mechanism of (bio)polyelectrolyte complexes formation have been discussed. It was shown that the complex formation takes place not only due to the hydrogen bonds, but also due to the electrostatic interactions between the positively charged amino-groups of chitosan and negatively charged amino acid residues (glutamic Glu and aspartic Asp acids) of gelatin.

Cation Exchange Resins and colonic perforation. What surgeons need to know.

INTRODUCTION: Since 1961 the use of Cation Exchange Resins has been the mainstream treatment for chronic hyperkalemia. For the past 25 years different kind of complications derived from its clinical use have been recognized, being the colonic necrosis the most feared and lethal of all. PRESENTATION OF CASE: We report a case of a 72-year-old patient with chronic kidney disease, treated with calcium polystyrene sulfonate for hyperkalemia treatment who presented in the emergency department with constipation treated with hypertonic cathartics. With clinical deterioration 48h later progressed with colonic necrosis requiring urgent laparotomy, sigmoidectomy and open abdomen management with subsequent rectal stump perforation and dead. The histopathology finding: calcium polystyrene sulfonate embedded in the mucosa, consistent with the cause of perforation. DISCUSSION: Lillemoe reported the first case series of five uremic patients with colonic perforation associated with the use of SPS in sorbitol in 1987 and in 2009 the FDA removed from the market the SPS containing 70% of sorbitol. The pathophysiologic change of CER goes from mucosal edema, ulcers, pseudomembranes, and the most severe case transmural necrosis. Up to present day, some authors have questioned the use of CER in the setting of lowering serum potassium. Despite its worldwide use in hyperkalemia settings, multiple studies have not demonstrated a significant potassium excretion by CER. CONCLUSION: Despite the low incidence of colonic complication and lethal colonic necrosis associated with the CER clinical use, the general surgeon needs a high index of suspicion when dealing with patients treated with CER and abdominal pain.

Intestinal Necrosis Associated with Orally Administered Calcium Polystyrene Sulfonate Without Sorbitol.

OBJECTIVE: To describe a case of extensive intestinal necrosis with oral intake of calcium polystyrene sulfonate without sorbitol. CASE SUMMARY: A 73-year-old woman was admitted to the emergency department with abdominal pain. Abdominal computed tomography (CT) scan showed widespread dilatation of the bowel. The diagnosis of acute colonic pseudoobstruction was made. On day 3, her serum potassium level rose to 5.6 mEq/L. It was treated with hydrocortisone 100 mg/day and calcium polystyrene sulfonate 15 g/day via nasogastric tube from day 3 to day 6. On day 6, the severe abdominal pain recurred, with abdominal tenderness. CT scan showed pneumoperitoneum and peritoneal effusion. At surgery, 2 lenticular jejunal perforations and an ischemic cecum were found. Microscopic findings indicated that the transmural abscess contained massive inflammatory infiltrate and the cecal mucosa showed ulceration and inflammation with a fibrinous and purulent coating. Small gray-purple or blue angulated crystals were embedded in the cecal and most of the jejunal mucosal ulcers. On day 19, the patient died of multiple organ failure after her third laparotomy. DISCUSSION: Ion-exchanging resins are given orally or by retention enema for the treatment of hyperkalemia. The most commonly used and best-established resin is sodium polystyrene sulfonate. However, it is known to promote colonic necrosis when sorbitol is also given or especially in patients with renal failure or postoperative ileus. Calcium polystyrene sulfonate is another ion-exchange resin. There are few reports of adverse effects in the literature. Our case is interesting for 2 reasons: the resin given was calcium polystyrene sulfonate and sorbitol was not used. CONCLUSIONS: Like sodium polystyrene sulfonate, calcium polystyrene sulfonate is an ion-exchanging resin that can promote bowel necrosis. We believe that it should not be used with sorbitol or when bowel transit time is slowed.