Unexpectedly severe metabolic acidosis associated with sodium thiosulfate therapy in a patient with calcific uremic arteriolopathy

Clinical characteristics and treatment modalities in uremic and non uremic calciphylaxis - a dermatological single-center experience

Calciphylaxis (CP) is a serious, potentially life-threatening disease that presents with medial calcification of small-sized vessels and painful ischemic ulcerations. Although calciphylaxis is frequently seen in patients with end-stage kidney disease on dialysis (calcific uremic arteriolopathy, CUA), there are reported cases of nonuremic calciphylaxis (NUC), which often remain undiagnosed. We conducted a retrospective chart review at our dermatological hospital and evaluated data concerning the epidemiology, comorbidities, medication, laboratory abnormalities, and therapeutic approaches of 60 patients diagnosed with calciphylaxis between 01/2012 and 12/2022. We identified 21 patients diagnosed with NUC and 39 with kidney disease. The predilection sites of skin lesions were the lower legs in 88% (n = 53), followed by the thigh and gluteal regions in 7% (n = 4). Significant differences were identified in comorbidities, such as atrial fibrillation (p < 0.001) and hyperparathyroidism (p < 0.01) accounting for CUA patients. Medication with vitamin K antagonists (p < 0.001), phosphate binders (p < 0.001), and loop diuretics (p < 0.01) was found to be associated with the onset of calciphylaxis. Hyperphosphatemia (p < 0.001), increased parathyroid hormone (p < 0.01) and triglyceride levels (p < 0.01), hypoalbuminemia (p < 0.01) and decreased hemoglobin values (p < 0.001) in the CUA cohort were significantly different from those in the NUC group. All patients with CUA received systemic medication. In contrast, only 38% (n = 8) of patients with NUC received systemic treatment. Striking discrepancies in the treatment of both cohorts were detected. In particular, NUC remains a disease pattern that is still poorly understood and differs from CUA in several important parameters.

The 2022 PSOGI International Consensus on HIPEC Regimens for Peritoneal Malignancies: HIPEC Technologies

This manuscript reports the results of an international consensus on technologies of hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) performed with the following goals: To provide recommendations for the technological parameters to perform HIPEC. To identify the role of heat and its application forms in treating peritoneal metastases. To provide recommendations regarding the correct dosimetry of intraperitoneal chemotherapy drugs and their carrier solutions. To identify for each intraperitoneal chemotherapy regimen the best dosimetry and fractionation. To identify areas of future research pertaining to HIPEC technology and regimens. This consensus was performed by the Delphi technique and comprised two rounds of voting. In total, 96 of 102 eligible panelists replied to both Delphi rounds (94.1%) with a consensus of 39/51 questions on HIPEC technical aspects. Among the recommendations that met with the strongest consensus were those concerning the dose of HIPEC drug established in mg/m2, a target temperature of at least 42°C, and the use of at least three temperature probes to pursue hyperthermia. Ninety minutes as the ideal HIPEC duration seemed to make consensus. These results should be considered when designing new clinical trials in patients with peritoneal surface malignancies.

Profound metabolic acidosis in association with sodium thiosulfate therapy in a patient with calcific uremic arteriolopathy: a case report and literature review

Calciphylaxis, also known as Calcific uremic arteriolopathy (CUA), is a serious disorder that presents with skin necrosis due to calcification of dermal and subcutaneous adipose tissue capillaries and arterioles. The condition occurs primarily in patients with end-stage renal disease (ESRD) on dialysis, and it carries high morbidity and mortality, primarily due to sepsis, with an estimated six-month survival of approximately 50%. Although there are no high-quality studies to guide the optimal treatment approach for patients with calciphylaxis, many retrospective studies and case series support treatment with sodium thiosulfate (STS). Despite the frequent use of STS as an off-label treatment, data regarding its safety and efficacy are limited. STS has generally been considered a safe drug with mild side effects. However, severe metabolic acidosis associated with STS is a rare and life-threatening complication of STS treatment and is often unpredictable. Herein, we report a 64-year-old female with ESRD on peritoneal dialysis (PD) who presented with a profound high anion gap metabolic acidosis and severe hyperkalemia while on STS treatment for CUA. No other etiology for her severe metabolic acidosis other than STS was identified. ESRD patients receiving STS should be monitored closely for this side effect. Dose reduction, increasing the duration of infusion, or even discontinuing STS treatment should be considered if severe metabolic acidosis develops.

Calciphylaxis and its co-occurrence with connective tissue diseases

Calciphylaxis, also known as calcific uremic arteriopathy, is a rare calcification syndrome that presents as ischemic skin necrosis and severe pain. It has a high mortality rate and is characterised by calcification of the small and medium arteries and micro-thrombosis. Calciphylaxis mainly occurs in patients with end-stage renal disease. In recent years, there have been an increasing number of cases of calciphylaxis associated with connective tissue diseases. Given the absence of clear diagnostic criteria for calciphylaxis thus far, an early diagnosis is crucial for designing an effective multidisciplinary treatment plan. In this article, we review the research progress on calciphylaxis and describe its characteristics in the context of connective tissue diseases.

Intravenous sodium thiosulphate for vascular calcification of hemodialysis patients-a systematic review and meta-analysis

BACKGROUND

Vascular calcification (VC) is a common comorbidity among patients with chronic kidney disease (CKD), indicating major cardiovascular events. This study aimed to evaluate the effects and safety of intravenous sodium thiosulphate (STS) for VC in CKD patients.

METHODS

Electronic databases were searched for clinical trials that provided data comparing outcomes among patients treated with and without STS. The PRISMA guidelines were followed. Efficacy was assessed using calcification scores and arterial stiffness. Safety was examined by analyzing adverse symptoms, electrolytes and bone mineral density (BMD). Random-effects models were performed. Meta-regression and sensitivity analysis were done. The risk of bias was assessed using the Cochrane tools.

RESULTS

Among the 5601 publications, 6 studies involving 305 participants (mean age: 56 years, male: 56.6%) with all participants on maintenance hemodialysis met eligibility criteria. For efficacy, the progression in Agatston scores in the coronary arteries [107 patients, mean difference (MD): -241.27, 95% confidence interval (95% CI): -421.50 to -61.03] and iliac arteries (55 patients, MD: -382.00, 95% CI: -751.07 to -12.93) was lower in the STS treated group compared with controls. The increase in pulse wave velocity was lower in the STS group (104 patients, MD: -1.29 m/s, 95% CI: -2.24 to -0.34 m/s). No association was found between the change in calcification scores and STS regimen. For safety, gastrointestinal symptoms (e.g. nausea) and increased anion gap acidosis were noted. No reduction in BMD by STS was observed.

CONCLUSIONS

Intravenous STS may attenuate the progression of VC and arterial stiffness in hemodialysis patients. Large and well-designed randomized controlled trials are warranted.

Sodium thiosulfate through preserving mitochondrial dynamics ameliorates oxidative stress induced renal apoptosis and ferroptosis in 5/6 nephrectomized rats with chronic kidney diseases

Chronic kidney disease (CKD) progression may be evoked through dysregulated mitochondrial dynamics enhanced oxidative stress and inflammation contributing to high cardiovascular morbidity and mortality. Previous study has demonstrated sodium thiosulfate (STS, Na2S2O3) could effectively attenuate renal oxidative injury in the animal model of renovascular hypertension. We explored whether the potentially therapeutic effect of STS is available on the attenuating CKD injury in thirty-six male Wistar rats with 5/6 nephrectomy. We determined the STS effect on reactive oxygen species (ROS) amount in vitro and in vivo by an ultrasensitive chemiluminescence-amplification method, ED-1 mediated inflammation, Masson's trichrome stained fibrosis, mitochondrial dynamics (fission and fusion) and two types of programmed cell death, apoptosis and ferroptosis by western blot and immunohistochemistry. Our in vitro data showed STS displayed the strongest scavenging ROS activity at the dosage of 0.1 g. We applied STS at 0.1 g/kg intraperitoneally 5 times/week for 4 weeks to these CKD rats. CKD significantly enhanced the degree in arterial blood pressure, urinary protein, BUN, creatinine, blood and kidney ROS amount, leukocytes infiltration, renal 4-HNE expression, fibrosis, dynamin-related protein 1 (Drp1) mediated mitochondrial fission, Bax/c-caspase 9/c-caspase 3/poly (ADP-ribose) polymerase (PARP) mediated apoptosis, iron overload/ferroptosis and the decreased xCT/GPX4 expression and OPA-1 mediated mitochondrial fusion. STS treatment significantly ameliorated oxidative stress, leukocyte infiltration, fibrosis, apoptosis and ferroptosis and improved mitochondrial dynamics and renal dysfunction in CKD rats. Our results suggest that STS as drug repurposing strategy could attenuate CKD injury through the action of anti-mitochondrial fission, anti-inflammation, anti-fibrosis, anti-apoptotic, and anti-ferroptotic mechanisms.

Forensic implication of seized drug imitating methamphetamine with mileage in crime

Background

The increase in drug abuse a major global issue. Clandestine laboratories along with illegal drug trafficking and trade increase the menace. Increased confiscation of illicit drugs not only indicates the manifold rise in drug abuse in Delhi and its neighboring region but also signifies an escalation and proliferation in other drug-related criminal activities. Investigating agencies around the world are working hard to combat and eradicate this problem. The samples seized by these agencies are subsequently sent for forensic examination to rule out the presence of any illicit drugs. Few such seized crystalline samples such as “methamphetamine” were submitted for examination with a query for the identification of any scheduled substance. The analysis outline followed was physical, chemical, Fourier transform infrared spectrometer analysis for detection, identification, and confirmation of seized drug samples. The purpose of a detailed investigation regarding the identification of the crystalline sample was also to understand the criminal activities involved in the consistent seizures and the forensics behind it.

Results

The comprehensive examination identified the sample as an inorganic salt of sodium thiosulfate with the absence of contraband methamphetamine. The study on salt-imitating methamphetamine underlines its diverse uses as in adulteration, trafficking to camouflage narcotics drug and its involvement in numerous other illegal purposes which on the other hand has a very crucial impact on society and its well-being.

Conclusions

The novel findings will update the investigating agencies and other experts regarding the importance of the detection of sodium thiosulfate salt in seized samples and will well establish the foul play behind large seizures to justify the role of forensic science. This unique finding deals with a very sensitive issue that has immense social impact and needs exceptional thoughtfulness.

The H2S Donor Sodium Thiosulfate (Na2S2O3) Does Not Improve Inflammation and Organ Damage After Hemorrhagic Shock in Cardiovascular Healthy Swine

We previously demonstrated marked lung-protective properties of the H2S donor sodium thiosulfate (Na2S2O3, STS) in a blinded, randomized, controlled, long-term, resuscitated porcine model of swine with coronary artery disease, i.e., with decreased expression of the H2S-producing enzyme cystathionine-γ-lyase (CSE). We confirmed these beneficial effects of STS by attenuation of lung, liver and kidney injury in mice with genetic CSE deletion (CSE-ko) undergoing trauma-and-hemorrhage and subsequent intensive care-based resuscitation. However, we had previously also shown that any possible efficacy of a therapeutic intervention in shock states depends both on the severity of shock as well as on the presence or absence of chronic underlying co-morbidity. Therefore, this prospective, randomized, controlled, blinded experimental study investigated the effects of the STS in cardiovascular healthy swine. After anesthesia and surgical instrumentation, 17 adult Bretoncelles-Meishan-Willebrand pigs were subjected to 3 hours of hemorrhage by removal of 30% of the blood volume and titration of the mean arterial pressure (MAP) ≈ 40 ± 5 mmHg. Afterwards, the animals received standardized resuscitation including re-transfusion of shed blood, fluids, and, if needed, continuous i.v. noradrenaline to maintain MAP at pre-shock values. Animals were randomly allocated to either receive Na2S2O3 or vehicle control starting 2 hours after initiation of shock until 24 hours of resuscitation. The administration of Na2S2O3 did not alter survival during the observation period of 68 hours after the initiation of shock. No differences in cardio-circulatory functions were noted despite a significantly higher cardiac output, which coincided with significantly more pronounced lactic acidosis at 24 hours of resuscitation in the Na2S2O3 group. Parameters of liver, lung, and kidney function and injury were similar in both groups. However, urine output was significantly higher in the Na2S2O3 group at 24 hours of treatment. Taken together, this study reports no beneficial effect of Na2S2O3 in a clinically relevant model of hemorrhagic shock-and-resuscitation in animals without underlying chronic cardiovascular co-morbidity.

Sodium thiosulfate protects from renal impairement following hyperthermic intraperitoneal chemotherapy (HIPEC) with Cisplatin

BACKGROUND

Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has been shown to provide benefits in the management of peritoneal metastasis. Cisplatin (CDDP) is one of the most frequently used drugs for peritoneal infusion. A major restriction is that CDDP causes renal toxicity and acute renal failure, sometimes leading to chronic renal failure. The aim of the present study was to assess the impact of sodium thiosulfate (ST) in preventing renal impairment (RI) following HIPEC with CDDP.

METHODS

This prospective study assessed the RI rates for all patients who underwent HIPEC with CDDP during two successive periods: without ST (nST Period; from November 2016 to September 2017) and with ST (ST Period; from October 2017 to March 2018). During the ST Period, patients received an ST infusion at 9 mg/m² prior to HIPEC and at 12 mg/m² at the end of the procedure. RI was defined by postoperative serum creatinine >1.6 times elevation of baseline value. The impact of ST treatment was evaluated by comparison of the RI rates between the two periods.

RESULTS

During ST Period, none of 38 patients (0%) developed RI versus 11/35 patients (31.4%) during the nST Period (p < .005); 2 of whom required definitive hemodialysis. Baseline characteristics, background circumstances, indications and laboratory parameters before HIPEC were comparable between the two groups, as well as CDDP dose use during HIPEC.

CONCLUSION

ST appears to be an effective drug for the prevention of the renal toxicity of CDDP used for HIPEC and should be used for all such procedures.

Sodium Thiosulfate Ameliorates Renovascular Hypertension-Induced Renal Dysfunction and Injury in Rats

BACKGROUND/AIMS

Arterial stenosis activates the renin-angiotensin-aldosterone system subsequently resulting in renovascular hypertension (RVHT) and renal oxidative injury. We explored the effect of sodium thiosulfate (STS, Na2S2O3), a developed antioxidant in clinical trial, on RVHT-induced hypertension and renal oxidative injury in rats.

METHODS

We induced RVHT in male Wistar rats with bilaterally partial ligation of renal arteries in the 2-kidney 2-clip model. We evaluated the STS effect on RVHT-induced oxidative injury and apoptosis by a chemiluminescence amplification method, Western blot, and immunohistochemistry.

RESULTS

We found STS displayed a dose-dependent antioxidant H2O2 activity and adapted the maximal scavenging H2O2 activity of STS at the dosage of 0.1 g/kg intraperitoneally 3 times/week for 4 weeks in RVHT rats. RVHT induced a significant elevation of arterial blood pressure, blood reactive oxygen species amount, neutrophil infiltration, 4-HNE and NADPH oxidase gp91 expression, Bax/Bcl-2/poly(ADP-ribose) polymerase (PARP)-mediated apoptosis formation, blue Masson-stained fibrosis, and urinary protein level. STS treatment significantly reduced hypertension, oxidative stress, neutrophil infiltration, fibrosis, and Bax/Bcl-2/PARP-mediated apoptosis formation and depressed the urinary protein level in the RVHT models.

CONCLUSION

Our results suggest that STS treatment could ameliorate RVHT hypertension and renal oxidative injury through antioxidant, antifibrotic, and antiapoptotic mechanisms.

Generalized Arterial Calcification of Infancy: New Insights, Controversies, and Approach to Management

PURPOSE OF REVIEW

This review summarizes current understanding of generalized arterial calcification of infancy (GACI), emphasizing pathophysiology, clinical presentation, and approaches and controversies in management.

RECENT FINDINGS

Identification of causative ENPP1 mutations revealed that GACI arises from deficiencies in inorganic pyrophosphate (leading to calcifications) and adenosine monophosphate (leading to intimal proliferation). Identification of genotypic and phenotypic overlap with pseudoxanthoma elasticum and autosomal recessive hypophosphatemic rickets further advanced understanding of GACI as a complex, multisystemic disease. Clinical data is limited to small, retrospective samples; it is therefore unknown whether commonly used medications, such as bisphosphonates and hypophosphatemia treatment, are therapeutic or potentially harmful. ENPP1-Fc replacement represents a promising approach warranting further study. Knowledge gaps in natural history place clinicians at high risk of assigning causality to interventions that are correlated with changes in clinical status. There is thus a critical need for improved natural history studies to develop and test targeted therapies.

Systematic review of sodium thiosulfate in treating calciphylaxis in chronic kidney disease patients

AIM

Calciphylaxis is a severe complication of advanced chronic kidney disease (CKD). Sodium thiosulphate (STS), an antioxidant and calcium chelating agent, has been used for the treatment of calciphylaxis. However, its efficacy and safety have not been systematically analysed and evaluated.

METHODS

MEDLINE, EMBASE, and the Cochrane Library database were systematically searched for case report or cases series on use of STS for calciphylaxis published between July 1974 and October 2016. We extracted data on clinical characteristics, laboratory tests result and medication use. The effective treatment was defined as improvement in skin lesion cicatrisation or pain relief without death. Non-responding effects were defined as stable skin lesions without remission or exacerbation of the disease in patients who remained alive. All-cause mortality after STS treatment was defined as death due to exacerbations of calciphylaxis or other complications of advanced CKD. We compared the baseline parameters of the patients as well as the efficacy and mortality of the STS therapy between case report and multi-case reports. Statistical analyses were performed using SPSS 19.

RESULTS

A total of 83 papers were screened, 45 of them (n = 358) met the inclusion criteria, including 36 case reports (n = 64) and nine multi-case reports (n = 294). The mean age of the patients with calciphylaxis was 58 ± 14 years (range 26-91 years). They were female predominant, accounting for 74.1%. Among the patients with calciphylaxis, 96.1% patients were on dialysis with median dialysis vintage of 44.5 months (range 24-84 months). STS was effective in 70.1% of patients, 37.6% patients died. The proportion of patients with sepsis was higher among those who received intravenous STS. There was no significant difference in efficacy between the different STS administration methods (P = 0.19).

CONCLUSION

Although the study was unable to assess the efficacy of sodium thiosulphate alone in the treatment of calciphylaxis, it still reveals a promising role of STS as an effective therapy for calciphylaxis. Further prospective studies to define the optimal therapy for calciphylaxis are needed.

An Update on Calciphylaxis

Calciphylaxis, also known as calcific uremic arteriolopathy and uremic small artery disease with medial wall calcification and intimal hyperplasia, is a multifactorial cutaneous vascular disease characterized by chronic, painful, non-healing wounds that occur frequently in patients with chronic kidney disease, predominantly in those with end-stage renal disease. The pathogenesis remains unclear, and the development of calciphylaxis lesions depends on medial calcification, intimal fibrosis of arterioles and thrombotic occlusion. Despite an increase in reports of calciphylaxis in the literature and clinical recognition of demographic characteristics and risk factors associated with calciphylaxis, it remains a poorly understood disease with high morbidity and mortality. In this review, we analyze and summarize the clinical manifestations, pathogenesis and pathophysiology, histopathology, differential diagnosis, diagnostic workup and treatment modalities for calciphylaxis. Because of the lack of consensus regarding the optimal approach to and treatment of this disorder, a high degree of clinical suspicion, early diagnosis, and multimodal and multidisciplinary treatment in collaboration with dermatology, nephrology, wound care, nutrition and pain management specialties may improve survival in patients with calciphylaxis.

The Use of Antidotes for Calcium Gluconate Extravasation: An Experimental Study in Mice

BACKGROUND

Calcium gluconate extravasation is a process that can cause serious lesions, such as necrosis and calcification of the soft tissues. The aim of the present study was to analyze the beneficial effects of four possible local antidotes for calcium gluconate extravasation: hyaluronidase, sodium thiosulfate, triamcinolone acetonide, and physiologic saline solution.

METHODS

Seventy-four BALB/c mice were used in the study. The substances selected for use in this study were calcium gluconate (4.6 mEq/ml), hyaluronidase (1500 IU/ml), sodium thiosulfate (25%), triamcinolone acetonide (40 mg/ml 0.5 mg/kg), and saline solution 0.9%. Five minutes were allowed to lapse after the calcium gluconate infiltration, and then an antidote was infiltrated. After 3 weeks, a skin biopsy was performed and a radiographic and histologic study was carried out.

RESULTS

Only in the group infiltrated with sodium thiosulfate did all skin lesions disappear after the 3-week period after infiltration. In the radiographic study, calcium deposits larger than 0.5 mm were observed in 40 percent of cases without an antidote, in 33 percent with triamcinolone acetonide, in 13 percent with a saline solution, and in none with thiosulfate and hyaluronidase. In the histologic study, calcium deposits were found in 53 percent of cases without antidote, 100 percent of cases with triamcinolone acetonide, 33 percent of cases with saline solution, and 13 percent of cases with sodium thiosulfate or hyaluronidase.

CONCLUSION

Sodium thiosulfate and hyaluronidase prevent the development of calcium deposits after calcium gluconate extravasation.

Case Report of Calciphylaxis Secondary to Calcium and Vitamin D3 Supplementation

BACKGROUND

Calciphylaxis is a rare disorder that is very unusual outside the setting of end-stage kidney disease.

CASE SUMMARY

A 64-year-old woman with normal renal function presented with painful leg ulcers. She had previously received 300 000 IU of vitamin D₃ followed by daily calcium and vitamin D₃ supplementation. A skin biopsy was consistent with calciphylaxis, and she was treated with sodium thiosulphate infusions and wound debridement.

CONCLUSION

Calcium and vitamin D₃ supplements are widely prescribed. We report a case of calciphylaxis triggered by calcium and vitamin D₃ supplementation in a patient with none of the typical risk factors. Our patient had an excellent response to treatment with sodium thiosulphate.

Multidisciplinary approach to calcific uremic arteriolopathy

PURPOSE OF REVIEW

Calcific uremic arteriolopathy (CUA), as known as calciphylaxis, is a rare and poorly understood disease seen predominantly in end stage renal disease patients. A collaborative multidisciplinary approach to develop and implement treatment and prevention methods is described.

RECENT FINDINGS

Overall, the scientific literature on CUA is largely restricted to case reports and case series. Recent reports indicate that the incidence of CUA may be on the rise and emphasize an association with vitamin K antagonist therapy, obesity, and diabetes mellitus. Serum calcium, phosphorous, and parathyroid hormone levels have been reported to be quite variable in patients with CUA and may reflect the heterogeneity of study designs. A multidisciplinary and multimodal approach that incorporates wound and pain management, sodium thiosulfate, optimization of mineral bone parameters, bisphosphonates, and avoidance of risk factors such as vitamin K antagonist has been advocated in the latest reports. Sodium thiosulfate although used frequently to treat CUA has unclear efficacy requiring further examination.

SUMMARY

This review describes the recent literature in the field of CUA including its limitations. It provides a summary of a multidisciplinary approach to CUA management.

Preeclampsia: Updates in Pathogenesis, Definitions, and Guidelines

Preeclampsia is becoming an increasingly common diagnosis in the developed world and remains a high cause of maternal and fetal morbidity and mortality in the developing world. Delay in childbearing in the developed world feeds into the risk factors associated with preeclampsia, which include older maternal age, obesity, and/or vascular diseases. Inadequate prenatal care partially explains the persistent high prevalence in the developing world. In this review, we begin by presenting the most recent concepts in the pathogenesis of preeclampsia. Upstream triggers of the well described angiogenic pathways, such as the heme oxygenase and hydrogen sulfide pathways, as well as the roles of autoantibodies, misfolded proteins, nitric oxide, and oxidative stress will be described. We also detail updated definitions, classification schema, and treatment targets of hypertensive disorders of pregnancy put forth by obstetric and hypertensive societies throughout the world. The shift has been made to view preeclampsia as a systemic disease with widespread endothelial damage and the potential to affect future cardiovascular diseases rather than a self-limited occurrence. At the very least, we now know that preeclampsia does not end with delivery of the placenta. We conclude by summarizing the latest strategies for prevention and treatment of preeclampsia. A better understanding of this entity will help in the care of at-risk women before delivery and for decades after.

The Successful Treatment of Calciphylaxis with Sodium Thiosulfate and Hyperbaric Oxygen in a Non-dialyzed Patient with Chronic Kidney Disease

We present the case of a non-dialyzed patient with chronic kidney disease and biopsy-proven calciphylaxis who presented with painful cutaneous ulcers on both legs. The skin ulcers drastically improved within 6 months after the initiation of hemodialysis, aggressive wound care, the control of a mineral and bone disorder, and the administration of sodium thiosulfate and hyperbaric oxygen therapy. Notably, the patient's serum levels of C-reactive protein and calciprotein particles decreased and her serum albumin and fetuin-A levels increased in parallel with the alleviation of her calciphylaxis. This case highlights the importance of applying combined medical treatment to calciphylaxis and suggests the possible involvement of calciprotein particles in the pathogenesis of calciphylaxis.

Calciphylaxis: risk factors, diagnosis, and treatment

Calciphylaxis is a rare but devastating condition that has continued to challenge the medical community since its early descriptions in the scientific literature many decades ago. It is predominantly seen in patients with chronic kidney failure treated with dialysis (uremic calciphylaxis) but is also described in patients with earlier stages of chronic kidney disease and with normal kidney function. In this review, we discuss the available medical literature regarding risk factors, diagnosis, and treatment of both uremic and nonuremic calciphylaxis. High-quality evidence for the evaluation and management of calciphylaxis is lacking at this time due to its rare incidence and poorly understood pathogenesis and the relative paucity of collaborative research efforts. We hereby provide a summary of recommendations developed by a multidisciplinary team for patients with calciphylaxis.

Successfully treated calcific uremic arteriolopathy: two cases of a high anion gap metabolic acidosis with intravenous sodium thiosulfate

Calcific uremic arteriolopathy (CUA) is a rare and potentially fatal disorder of calcification involving subcutaneous small vessels and fat in patients with renal insufficiency. We describe the successful use of intravenous sodium thiosulfate (STS) for the treatment of CUA in two patients. The first case was complicated by the development of a severe anion gap metabolic acidosis, which was accompanied by a seizure. Both patients had complete wound healing within five months. Although STS should be considered in the treatment of CUA, little is known about pharmacokinetics and additional studies are required to determine dosing strategies to minimize severe potential side effects.

Severe anion gap acidosis associated with intravenous sodium thiosulfate administration

INTRODUCTION

Severe anion gap (AG) acidosis associated with intravenous sodium thiosulfate (STS) administration has not been previously described in nondialysis chronic kidney disease (CKD) patients.

CASE REPORT

We present a CKD patient with a baseline creatinine 1.8 mg/dL (eGFR 28 ml/min/1.73 m²) who developed sustained and life-threatening AG acidosis associated with intravenous STS treatment for calciphylaxis.

DISCUSSION

Although marketed as a safe drug, STS can cause life-threatening acidosis as illustrated in this case. STS-induced AG acidosis should be considered in the differential diagnosis of severe acidosis in patients receiving STS. Dosage adjustment and close follow-up of patients' acid-base status after STS initiation is necessary.

Falsely increased chloride and missed anion gap elevation during treatment with sodium thiosulfate

BACKGROUND

Sodium thiosulfate (STS) is used to treat calciphylaxis and cyanide poisoning, but can lead to a serious anion-gap acidosis. We suspected that the calculated anion gap in a patient treated with STS for calciphylaxis was decreased to normal by a falsely increased chloride, and we hypothesized that STS directly interfered with chloride measurements.

METHODS

Plasma pools were prepared with 12 concentrations of STS from 0 to 20 mmol/l. Chloride was measured in each sample on 9 analyzers: Architect 16200, StatProfile pHOx Plus, RapidLab 1265®, Vitros 350®, Advia 1800, Roche Modular, iSTAT1, RAPIDpoint 500, and Radiometer ABL735.

RESULTS

Statistically significant, dose-dependent increases in reported chloride concentrations were seen with all analyzers except the RAPIDpoint 500 and Vitros. The increases ranged from 5 to 75 mmol/l at the peak thiosulfate concentrations (33 mmol/l) expected in treated patients. The CLIA-allowable error of 5% was exceeded by 4 analyzers (Architect 16200, iSTAT1, StatProfile pHOx Plus, and Radiometer ABL735). The RAPIDpoint 500 showed a 3-mmol/l decrease in measured chloride over the tested range. The Vitros analyzer showed no interference.

CONCLUSIONS

Interference of STS in chloride measurement in several common analyzers may lead to erroneous anion-gap calculations and confound the diagnosis of STS-induced anion-gap acidosis.

A pilot study of the effect of sodium thiosulfate on urinary lithogenicity and associated metabolic acid load in non-stone formers and stone formers with hypercalciuria

Background and Objectives

Sodium thiosulfate (STS) reduced calcium stone formation in both humans and genetic hypercalciuric stone forming (GHS) rats. We sought to measure urine chemistry changes resulting from STS administration in people.

Design, Setting, Participants & Measurements

STS was given to healthy and hypercalciuric stone forming adults. Five normal non-stone forming adults (mean age 33 years), and 5 people with idiopathic hypercalciuria and calcium kidney stones (mean age 66 years) participated. Two baseline 24-hour urine collections were performed on days 2 and 3 of 3 days of self-selected diets. Subjects then drank STS 10 mmol twice a day for 7 days and did urine collections while repeating the self-selected diet. Results were compared by non-parametric Wilcoxon signed rank test. The primary outcome was the resulting change in urine chemistry.

Results

STS administration did not cause a significant change in urinary calcium excretion in either group. In both groups, 24 hour urinary ammonium (P = 0.005) and sulfate excretion (P = 0.007) increased, and urinary pH fell (P = 0.005); citrate excretion fell (P<0.05) in hypercalciuric participants but not in non-stone formers. Among stone formers with hypercalciuria, 3 of 5 patients had measurement of serum HCO₃ concentration after the STS period: it did not change. The net effect was an increase in supersaturation of uric acid, and no change in supersaturation of calcium oxalate or calcium phosphate.

Conclusions

The basis for studies demonstrating that STS prevented stones in rats and people was not reflected by the changes in urine chemistry reported here. Although serum HCO₃ did not change, urine tests suggested an acid load in both non-stone forming and hypercalciuric stone-forming participants. The long term safety of STS needs to be determined before the drug can be tested in humans for long-term prevention of stone recurrence.

Sodium thiosulfate therapy for calcific uremic arteriolopathy

BACKGROUND AND OBJECTIVE

Calcific uremic arteriolopathy (CUA) is an often fatal condition with no effective treatment. Multiple case reports and case series have described intravenous sodium thiosulfate (STS) administration in CUA, but no studies have systematically evaluated this treatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study included 172 patients undergoing maintenance hemodialysis who had CUA and were treated with STS between August 2006 and June 2009 at Fresenius Medical Care North America. Of these, 85% completed STS therapy. Clinical, laboratory, and mortality data were abstracted from clinical information systems. Responses to survey questionnaires sent to treating physicians regarding patient-level outcomes were available for 53 patients. Effect on CUA lesions and mortality were summarized as CUA outcomes. Relevant laboratory measures, weight (using pairwise comparisons of values before, during, and after STS), and adverse events were summarized as safety parameters.

RESULTS

Mean age of the cohort was 55 years, and 74% of patients were women. Median STS dose was 25 g, and median number of doses was 38. Among surveyed patients, CUA completely resolved in 26.4%, markedly improved in 18.9%, improved in 28.3%, and did not improve in 5.7%; in the remaining patients (20.8%), the response was unknown. One-year mortality in patients treated with STS was 35%. Adverse events, laboratory abnormalities, and weight-related changes were mild. Significant reductions in serum phosphorous (P=0.02) and parathyroid hormone (P=0.01) were noted during STS treatment in patients who completed the therapy.

CONCLUSIONS

Although conclusive evidence regarding its efficacy is lacking, a majority of patients who received STS demonstrated clinical improvement in this study.