Haemolytic uremic syndrome: diagnosis and management

Renal Involvement in Thrombotic Thrombocytopenic Purpura: Is It Time to Challenge the Old Paradigm?

Thrombotic thrombocytopenic purpura (TTP) is clinical-pathological entity characterized by microangiopathic hemolytic anemia associated with end-organ dysfunction. Traditionally, TTP was characterized by the classic pentad of fever, thrombocytopenia, hemolytic anemia, renal impairment, and neurological manifestations. However, this classic pentad is only observed in 40% of cases. We herein describe the case of a female patient who presented with epigastric pain and vomiting and found to have TTP without the classic pentad but with rapidly progressive renal dysfunction.

Adult-onset Still's disease with concurrent thrombotic microangiopathy: Observations from pooled analysis for an uncommon finding

BACKGROUND

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder that is characterized by quotidian fevers, arthritis, and an evanescent rash. Occurrence of concurrent thrombotic microangiopathy (TMA) in AOSD is rare. The treatment aspects of TMA in AOSD are actively being debated.

METHODS

Medline search using MeSH terms and snowballing yielded a total of 29 articles with co-occurrence of AOSD and thrombotic thrombocytopenic purpura (TTP) including our own. Pooled data were synthesized for descriptive analysis.

RESULTS

Median age was 35 years with a majority of females (68.96%). A majority of these studies/patients were either Asian (34.48%) or Caucasian (31.03%). Concurrent TMA at the time of AOSD diagnosis was seen in 65.51% patients. Only 3/29 patients had ADAMTS13 level less than 10%, consistent with TTP and 3/29 were diagnosed with hemolytic uremic syndrome (HUS). The remainder were diagnosed clinically. Complication rate was high, and 15/29 (51.72%) patients died or had permanent neurological/renal/vision/gangrenous complications. Median and mean ferritin peak was observed to be higher (7458 and 12 349, respectively) in patients who either died/had partial remission, compared to those who had complete response (3257 and 10 899, respectively), p = .829.

CONCLUSIONS

A majority of patients with AOSD-associated TMA either died or had permanent complications. TMA was diagnosed alongside AOSD in 65% patients, while the rest developed TMA during the course of their disease. Blurred vision may precede TMA and could help risk-stratify high-risk AOSD patients clinically. Glycosylated ferritin remains low several weeks to months after disease remission and may be used to monitor severity of disease process. Further studies are necessary to confirm the existing vascular endothelial growth factor hypothesis in AOSD-associated TMA.

Thrombotic microangiopathy after kidney transplantation: Expanding etiologic and pathogenetic spectra

Thrombotic microangiopathy (TMA) is an uncommon but serious complication that not only affects native kidneys but also transplanted kidneys. This review is specifically focused on post-transplant TMA (PT-TMA) involving kidney transplant recipients. Its reported prevalence in the latter population varies from 0.8% to 14% with adverse impacts on both graft and patient survival. It has many causes and associations, and the list of etiologic agents and associations is growing constantly. The pathogenesis is equally varied and a variety of patho genetic pathways lead to the development of microvascular injury as the final common pathway. PT-TMA is categorized in many ways in order to facilitate its management. Ironically, more than one causes are contributory in PT-TMA and it is often difficult to pinpoint one particular cause in an individual case. Pathologically, the hallmark lesions are endothelial cell injury and intravascular thrombi affecting the microvasculature. Early diagnosis and classification of PT-TMA are imperative for optimal outcomes but are challenging for both clinicians and pathologists. The Banff classification has addressed this issue and has developed minimum diagnostic criteria for pathologic diagnosis of PT-TMA in the first phase. Management of the condition is also challenging and still largely empirical. It varies from simple maneuvers, such as plasmapheresis, drug withdrawal or modification, or dose reduction, to lifelong complement blockade, which is very expensive. A thorough understanding of the condition is imperative for an early diagnosis and quick treatment when the treatment is potentially effective. This review aims to increase the awareness of relevant stakeholders regarding this important, potentially treatable but under-recognized cause of kidney allograft dysfunction.

Shiga toxin targets the podocyte causing hemolytic uremic syndrome through endothelial complement activation

BACKGROUND

Shiga toxin (Stx)-producing Escherichia coli hemolytic uremic syndrome (STEC-HUS) is the leading cause of acute kidney injury in children, with an associated mortality of up to 5%. The mechanisms underlying STEC-HUS and why the glomerular microvasculature is so susceptible to injury following systemic Stx infection are unclear.

METHODS

Transgenic mice were engineered to express the Stx receptor (Gb3) exclusively in their kidney podocytes (Pod-Gb3) and challenged with systemic Stx. Human glomerular cell models and kidney biopsies from patients with STEC-HUS were also studied.

FINDINGS

Stx-challenged Pod-Gb3 mice developed STEC-HUS. This was mediated by a reduction in podocyte vascular endothelial growth factor A (VEGF-A), which led to loss of glomerular endothelial cell (GEnC) glycocalyx, a reduction in GEnC inhibitory complement factor H binding, and local activation of the complement pathway. Early therapeutic inhibition of the terminal complement pathway with a C5 inhibitor rescued this podocyte-driven, Stx-induced HUS phenotype.

CONCLUSIONS

This study potentially explains why systemic Stx exposure targets the glomerulus and supports the early use of terminal complement pathway inhibition in this devastating disease.

FUNDING

This work was supported by the UK Medical Research Council (MRC) (grant nos. G0901987 and MR/K010492/1) and Kidney Research UK (grant nos. TF_007_20151127, RP42/2012, and SP/FSGS1/2013). The Mary Lyon Center is part of the MRC Harwell Institute and is funded by the MRC (A410).

Recent Advances in the Management of Microangiopathic Hemolytic Anemias (MAHA): A Narrative Review

Red blood cells (RBCs) start to break down early in hemolytic anemia, which can be chronic or life-threatening. It should be considered while determining if normocytic or macrocytic anemia is present. Hemolysis in the reticuloendothelial system may happen intravascularly, extravascularly, or both. It accounts for a broad spectrum of laboratory and clinical situations, both physiological and pathological. Whenever the frequency of RBC breakdown is rapid enough to lower hemoglobin levels below the normal range, hemolytic anemia occurs. Microangiopathic hemolytic anemia (MAHA) is a term used to describe non-immune hemolysis induced by intravascular RBC fragmentation caused by substances in the tiny blood arteries that generate schistocytes in the peripheral circulation. Microvasculature abnormalities, such as small arterioles and capillaries, are usually involved. Furthermore, MAHA can also be brought on by intravascular devices like a prosthetic heart valve or assistive technologies. Poor deformity results in entrapment, phagocytosis, antibody-mediated elimination through phagocytosis or direct complement activation, fragmentation brought about by microthrombi or acute mechanical stress, oxidation, or spontaneous cellular death. Hemolysis may cause acute anemia, jaundice, hematuria, dyspnea, tiredness, tachycardia, and possibly hypotension. This article aims to synthesize existing research, identify therapeutic strategies, and provide insights into current and emerging approaches for managing this complex hematological disorder.

Etiological diagnosis of post-diarrheal hemolytic uremic syndrome (HUS): humoral response contribution

BACKGROUND

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolysis, thrombocytopenia, and thrombus formation leading to tissue injury. HUS is classified according to its etiology as post-diarrheal or atypical HUS. Differential diagnosis of both entities continues to be a challenge for pediatric physicians.

METHODS

The aim was to improve the rapid etiological diagnosis of post-diarrheal HUS cases based on the detection of Shiga toxin (Stx)-producing Escherichia coli (STEC) infection by screening of stx_1/stx₂ and rfb_O157 in cultured stools by multiplex PCR, and the additional detection of anti-lipopolysaccharide (anti-LPS) O157, O145, and O121 antibodies by Glyco-iELISA test. In addition, we studied patients' relatives to detect circulating pathogenic strains that could contribute to HUS diagnosis and/or lead to the implementation of measures to prevent dissemination of familial outbreaks. This study describes the diagnosis of 31 HUS patients admitted to Hospital Municipal de Niños Prof Dr Ramón Exeni during the 2017-2020 period.

RESULTS

Stool PCR confirmed the diagnosis of STEC associated with HUS in 38.7% of patients (12/31), while anti-LPS serology did in 88.9% (24/27). In those patients in which both methods were carried out (n = 27), a strong association between the results obtained was found. We found that 30.4% of HUS patients had at least one relative positive for STEC.

CONCLUSIONS

We could identify 96.3% (26/27) of HUS cases as secondary to STEC infections when both methods (genotyping and serology) were used. The results demonstrated a high circulation of STEC in HUS families and the prevalence of the STEC O157 serotype (83%) in our pediatric cohort. A higher-resolution version of the Graphical abstract is available as Supplementary information.

THROMBOTIC MICROANGIOPATHY: DIAGNOSTIC CHALLENGES IN THE PRIMARY MULTIPLE NEOPLASM INVOLVEMENT WITH PREVALENT METASTASIS WITH GRANULOMATOSIS INFLAMMATORY FOCUSES

Patient, who died during the hospital stay, had hemoblastosis and syphilis in the reported medical history. While the patient was examined doctors suspected the presence of malignancy with unknown primary localization with multiple metastatic injuries with clinical and laboratory TTP signs (hemorrhagic syndrome, thrombocytopenia, shystocytosis, and non-immune hemolytic anemia). Despite treatment, the general patient's condition progressively worsens with increasing multiple organ decompensation signs. In the final stage of the disease course, after heart arrest and the appearance of clinical death signs CPR measures were performed according to complete guidance, but CRP had no positive effect. Biological death was constated. Considering the criteria of the diagnostic clinical and laboratory dyad (thrombocytopenia and microangiopathic hemolytic anemia), the data of the patholog¬ical examination (multiple metastatic lesions, inflammatory process, tumor intoxication, thrombosis), the combination of manifestations of chronic myeloid leukemia, prostate cancer with multiple metastases, tertiary syphilis served as a condition for the initiation of TTP, which was of decisive importance in the development of the patient's death.

Atypical Hemolytic Uremic Syndrome after SARS-CoV-2 Infection: Report of Two Cases

Atypical hemolytic uremic syndrome (aHUS) is a life-threatening disease causing systemic thrombotic microangiopathy (TMA) due to the fact of complement dysregulation. Immune activation by viruses, including SARS-CoV-2, can lead to the development of an episode of aHUS against a background of genetic dysregulation in the complement pathway. This paper presents an analysis of two cases of aHUS-siblings diagnosed with familial disease, with a genetic predisposition to aHUS, in whom infection with SARS-CoV-2 was a strong trigger of disease recurrence. The quick recognition and treatment with eculizumab in the early stage of the disease resulted in a rapid improvement in clinical conditions and laboratory parameters.

The Management of Hypertensive Emergencies-Is There a "Magical" Prescription for All?

Hypertensive emergencies (HE) represent high cardiovascular risk situations defined by a severe increase in blood pressure (BP) associated with acute, hypertension mediated organ damage (A-HMOD) to the heart, brain, retina, kidneys, and large arteries. Blood pressure values alone do not accurately predict the presence of HE; therefore, the search for A-HMOD should be the first step in the management of acute severe hypertension. A rapid therapeutic intervention is mandatory in order to limit and promote regression of end-organ damage, minimize the risk of complications, and improve patient outcomes. Drug therapy for HE, target BP, and the speed of BP decrease are all dictated by the type of A-HMOD, specific drug pharmacokinetics, adverse drug effects, and comorbidities. Therefore, a tailored approach is warranted. However, there is currently a lack of solid evidence for the appropriate treatment strategies for most HE. This article reviews current pharmacological strategies while providing a stepwise, evidence based approach for the management of HE.

Clinical Observation on the Nursing Effect of Mindfulness-Based Stress Reduction Combined with Solution-Focused Brief Therapy in Uremic Peritoneal Dialysis Patients and Influence on Nutritional Status

Objective

To explore the nursing effect of mindfulness-based stress reduction (MBSR) combined with solution-focused brief therapy (SFBT) in uremic peritoneal dialysis (PD) patients and its influence on nutritional status.

Methods

A prospective study was conducted on 108 uremia patients undergoing PD who were admitted to the First People's Hospital of Wenling from March 2018 to December 2020. In accordance with the wishes of the patients, according to random number method, the patients were divided into control group (n = 54) and experimental group (n = 54). Patients in the control group were given routine care. Patients in the experimental group were given MBSR combined with SFBT. The clinical data, biochemical indicators, complication, compliance, nutritional status, and quality of life of the two groups were compared.

Results

After intervention, the serum hemoglobin, serum albumin levels, and urea clearance index of the experimental group were higher than those of the control group (P < 0.05). Compared with the control group, the experimental group had a lower incidence of complications (P < 0.05). After intervention, the compliance score of the experimental group was higher than that of the control group (P < 0.05). After intervention, the malnutrition inflammation score of the experimental group was lower than that of the control group (P < 0.05). After intervention, the Kidney Disease and Quality of Life-36 scores of the experimental group were higher than those of the control group (P < 0.05).

Conclusion

MBSR combined with SFBT has a good nursing effect in uremia patients undergoing PD and can increase the patient's treatment compliance, improve the quality of life, and improve the nutritional status.

Hemophagocytic lymphohistiocytosis during pregnancy: a review of the literature in epidemiology, pathogenesis, diagnosis and treatment

Hemophagocytic lymphohistiocytosis during pregnancy is rare; it is often misdiagnosed, resulting in a high maternal and foetal mortality rate. Herein, based on limited case reports including antepartum and postpartum cases, we reviewed the current studies of pregnancy-related hemophagocytic lymphohistiocytosis, and compared the epidemiology, aetiology, diagnosis and treatment of pregnancy-related hemophagocytic lymphohistiocytosis with non-pregnancy, enriching the understanding of hemophagocytic lymphohistiocytosis and its treatment in obstetrics.

Streptococcus Pneumoniae-Associated Hemolytic Uremic Syndrome in the Era of Pneumococcal Vaccine

Streptococcus pneumoniae-associated hemolytic uremic syndrome (Sp-HUS) is a serious complication of invasive pneumococcal disease that is associated with increased mortality in the acute phase and morbidity in the long term. Recently, Sp-HUS definition has undergone revision and cases are categorized as definite, probable, and possible, based on less invasive serological investigations that evaluate Thomsen-Friedenreich crypt antigen (T-antigen) activation. In comparison to the pre-vaccine era, Sp-HUS incidence seems to be decreasing after the introduction of 7-serotype valence and 13-serotype valence pneumococcal vaccines in 2000 and 2010, respectively. However, Sp-HUS cases continue to occur secondary to vaccine failure and emergence of non-vaccine/replacement serotypes. No single hypothesis elucidates the molecular basis for Sp-HUS occurrence, although pneumococcal neuraminidase production and formation of T-antigen antibody complexes on susceptible endothelial and red blood cells continues to remain the most acceptable explanation. Management of Sp-HUS patients remains supportive in nature and better outcomes are being reported secondary to earlier recognition, better diagnostic tools and improved medical care. Recently, the addition of eculizumab therapy in the management of Sp-HUS for control of dysregulated complement activity has demonstrated good outcomes, although randomized clinical trials are awaited. A sustained pneumococcal vaccination program and vigilance for replacement serotypes will be the key for persistent reduction in Sp-HUS cases worldwide.

Lessons learned from hemolytic uremic syndrome registries: recommendations for implementation

BACKGROUND

Hemolytic uremic syndrome (HUS) is a rare condition which diagnosed with the triad of thrombocytopenia, microangiopathic hemolytic anemia, and acute renal injury. There is a high requirement for research to discover treatments. HUS registries can be used as an important information infrastructure. In this study, we identified and compared the different features of HUS registries to present a guide for the development and implementation of HUS registries.

RESULTS

The purposes of registries were classified as clinical (9 registries), research (7 registries), and epidemiological (5 registries), and only 3 registries pursued all three types of purposes. The data set included demographic data, medical and family history, para-clinical and diagnostic measures, treatment and pharmacological data, complications, and outcomes. The assessment strategies of data quality included monthly evaluation and data audit, the participation of physicians to collect data, editing and correcting data errors, increasing the rate of data completion, following guidelines and data quality training, using specific data quality indicators, and real-time evaluation of data at the time of data entry. 8 registries include atypical HUS patients, and 7 registries include all patients regardless of age. Only two registries focused on children. 4 registries apply prospective and 4 applied both prospective, and retrospective data collection. Finally, specialized hospitals were the main data source for these registries.

CONCLUSION

Based on the findings, we suggested a learning framework for developing and implementing an HUS registry. This framework includes lessons learned and suggestions for HUS registry purposes, minimum data set, data quality assurance, data collection methods, inclusion and exclusion criteria as well as data sources. This framework can help researchers develop HUS registries.

Thrombotic Microangiopathy After Kidney Transplantation: An Underdiagnosed and Potentially Reversible Entity

Thrombotic microangiopathy is a rare but serious complication that affects kidney transplant recipients. It appears in 0.8–14% of transplanted patients and negatively affects graft and patient survival. It can appear in a systemic form, with hemolytic microangiopathic anemia, thrombocytopenia, and renal failure, or in a localized form, with progressive renal failure, proteinuria, or arterial hypertension. Post-transplant thrombotic microangiopathy is classified as recurrent atypical hemolytic uremic syndrome or de novo thrombotic microangiopathy. De novo thrombotic microangiopathy accounts for the majority of cases. Distinguishing between the 2 conditions can be difficult, given there is an overlap between them. Complement overactivation is the cornerstone of all post-transplant thrombotic microangiopathies, and has been demonstrated in the context of organ procurement, ischemia-reperfusion phenomena, immunosuppressive drugs, antibody-mediated rejection, viral infections, and post-transplant relapse of antiphospholipid antibody syndrome. Although treatment of the causative agents is usually the first line of treatment, this approach might not be sufficient. Plasma exchange typically resolves hematologic abnormalities but does not improve renal function. Complement blockade with eculizumab has been shown to be an effective therapy in post-transplant thrombotic microangiopathy, but it is necessary to define which patients can benefit from this therapy and when and how eculizumab should be used.

Labile Heme Aggravates Renal Inflammation and Complement Activation After Ischemia Reperfusion Injury

Background: Ischemia reperfusion injury (IRI) plays a major role in solid organ transplantation. The length of warm ischemia time is critical for the extent of tissue damage in renal IRI. In this experimental study we hypothesized that local release of labile heme in renal tissue is triggered by the duration of warm ischemia (15 vs. 45 min IRI) and mediates complement activation, cytokine release, and inflammation. Methods: To induce IRI, renal pedicle clamping was performed in male C57BL/6 mice for short (15 min) or prolonged (45 min) time periods. Two and 24 h after experimental ischemia tissue injury labile heme levels in the kidney were determined with an apo-horseradish peroxidase assay. Moreover, renal injury, cytokines, and C5a and C3a receptor (C5aR, C3aR) expression were determined by histology, immunohistochemistry and qPCR, respectively. In addition, in vitro studies stimulating bone marrow-derived macrophages with LPS and the combination of LPS and heme were performed and cytokine expression was measured. Results: Inflammation and local tissue injury correlated with the duration of warm ischemia time. Labile heme concentrations in renal tissue were significantly higher after prolonged (45 min) as compared to short (15 min) IRI. Notably, expression of the inducible heme-degrading enzyme heme oxygenase-1 (HO-1) was up-regulated in kidneys after prolonged, but not after short IRI. C5aR, the pro-inflammatory cytokines IL-6 and TNF-α as well as pERK were up-regulated after prolonged, but not after short ischemia times. Consecutively, neutrophil infiltration and up-regulation of pro-fibrotic cytokines such as CTGF and PAI were more pronounced in prolonged IRI in comparison to short IRI. In vitro stimulation of macrophages with LPS revealed that IL-6 expression was enhanced in the presence of heme. Finally, administration of the heme scavenger human serum albumin (HSA) reduced the expression of pro-inflammatory cytokines, C3a receptor and improved tubular function indicated by enhanced alpha 1 microglobulin (A1M) absorption after IRI. Conclusions: Our data show that prolonged duration of warm ischemia time increased labile heme levels in the kidney, which correlates with IRI-dependent inflammation and up-regulation of anaphylatoxin receptor expression.