Extra-renal manifestations of atypical hemolytic uremic syndrome

Combined liver-kidney transplantation in pediatric patients

Combined liver-kidney transplantation (CLKT) is a surgical procedure that involves transplanting both liver and kidney organs. There are two types of CLKT: simultaneous liver-kidney transplantation (smLKT) and sequential LKT (sqLKT). CLKT accounts for a small percentage of liver transplantations (LTs), particularly in pediatric cases. Nevertheless, the procedure has demonstrated excellent outcomes, with high survival rates and lower rejection rates. The main indications for CLKT in pediatric patients differ somewhat from that in adults, in which end-stage kidney disease after LT is the major indication. In children, congenital diseases are common reason for performing CLKT; the examples of such diseases include autosomal recessive polycystic kidney disease with congenital hepatic fibrosis which equally affects both organs, and primary hyperoxaluria type 1, a primary liver disease leading kidney failure. The decision between smLKT or sqLKT depends on the dominant organ failure, the specific pathophysiology, and available organ sources. However, there remain significant surgical and societal challenges surrounding CLKT. Innovations in pharmacology and genetic engineering have decreased the necessity for CLKT in early-diagnosed cases without portal hypertension or kidney replacement therapy. Nonetheless, these advancements are not universally accessible. Therefore, decision-making algorithms should be crafted, considering region-specific organ allocation systems and prevailing medical environments.

Outcome of atypical hemolytic uremic syndrome: role of triggers and complement abnormalities in the response to C5 inhibition

BACKGROUND

Atypical-hemolytic uremic syndrome (aHUS) is a rare thrombotic microangiopathy often due to uncontrolled complement activation, characterized by high risk of end-stage kidney disease (ESKD). Eculizumab has improved the outcome, however, its efficacy varies among patients and its discontinuation is debated.

METHODS

To identify characteristics associated with treatment response, we analyzed 244 aHUS patients referred to our center. Patients were classified according to the presence/absence of complement abnormalities and/or triggers at onset in 4 categories: (1) primary (complement abnormality without trigger), (2) secondary (trigger without complement abnormality), (3) combined (trigger and complement abnormality), (4) idiopathic (no trigger, no complement abnormality). Response to treatment was evaluated by comparing the response to eculizumab with that of conventional therapy. Short- and long-term outcomes were evaluated with the relapse rate after discontinuation of C5-inhibition.

RESULTS

Patients had a better outcome with eculizumab compared to conventional treatment, with a response rate of 81.9% vs 56.9%, p < 0.001 and a long-term cumulative incidence of ESKD of 5.8% vs 22.5% (hazard ratio 0.25, 95% confidence interval: 0.10-0.80). The excellent global response was driven by the primary and combined groups (89.8% vs 54.0% and 89.3% vs 54.2%, respectively). The relapse rate following discontinuation of the C5-inhibitor was as high as 66.7% in the primary group, 18.7% in the combined, and 0% in the secondary and idiopathic groups.

CONCLUSIONS

Our data show a better outcome in aHUS patients treated with C5-inhibition, particularly in the primary and combined forms, which have a high risk of relapse after discontinuation that is not observed in the secondary and idiopathic forms.

Pregnancy-Associated Atypical Hemolytic Uremic Syndrome: A Case Report with MCP Gene Mutation and Successful Eculizumab Treatment

Pregnancy-associated atypical hemolytic uremic syndrome (P-aHUS) is a rare condition characterized by microangiopathic hemolytic anemia and kidney injury from thrombotic microangiopathy. P-aHUS occurs in approximately 1 in 25,000 pregnancies and is strongly related to complement dysregulation and pregnancy-related disorders, such as preeclampsia, eclampsia, and hemolysis, elevated liver enzymes, low platelet (HELLP) syndrome, resulting in adverse perinatal and fetal outcomes. Complement dysregulation in P-aHUS is commonly attributed to genetic mutations or autoantibodies affecting complement factors, including CFH , CFI , and MCP. We present a case of a 25-year-old primigravida who experienced severe preeclampsia and HELLP syndrome followed by the development of complicated P-aHUS during the early postpartum period. The patient exhibited severe clinical manifestations, including hypertensive emergency, central nervous system involvement, renal impairment, and microangiopathic hemolytic anemia. Timely initiation of eculizumab therapy resulted in successful disease remission. Further genetic analysis revealed a likely rare pathogenic MCP gene variant.

Why has plasma exchange failed in TRACK syndrome? Lessons from a new variant of the atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is a rare and life-threatening form of thrombotic microangiopathy, associated with high mortality and morbidity. Most cases present with hemolytic anemia, thrombocytopenia, and renal insufficiency. However, it can have unusual multiple end-organ injuries including extrarenal organ and system involvements such as neurologic, cardiac, gastrointestinal, and respiratory systems. We describe a 4-year-old girl who developed aHUS due to the TSEN2 mutation and had cardiac involvement. She did not benefit from plasma exchange, as stated in previous cases. It should be kept in mind that therapeutic plasma exchange may not be beneficial in some cases of aHUS, especially due to genetic mutations.

Atypical Hemolytic-Uremic Syndrome: Genetic Basis, Clinical Manifestations, and a Multidisciplinary Approach to Management

Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy (TMA) defined by the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury. Microthrombi develop in the glomerular capillaries secondary to endothelial damage and exert shear stress on red blood cells, consume platelets, and contribute to renal dysfunction and failure. Per current understanding of pathophysiology, HUS is classified into infectious, secondary, and atypical disease. The most common etiology is infectious sequelae of Shiga toxin-producing Escherichia coli (STEC); other causative organisms include shigella and salmonella. Secondary HUS arises from cancer, chemotherapy, solid organ and hematopoietic stem cell transplant, pregnancy, or autoimmune disorders. Primary atypical hemolytic-uremic syndrome (aHUS) is associated with genetic mutations in complement and complement regulatory proteins. Under physiologic conditions, complement regulators keep the alternative complement system continuously active at low levels. In times of inflammation, mutations in complement-related proteins lead to uncontrolled complement activity. The hyperactive inflammatory state leads to glomerular endothelial damage, activation of the coagulation cascade, and TMA findings. Atypical hemolytic-uremic syndrome is a rare disorder with a prevalence of 2.21 to 9.4 per million people aged 20 years or younger; children between the ages of 0 and 4 are most affected. Multidisciplinary health care is necessary for timely management of its extra-renal manifestations. These include vascular disease of the heart, brain, and skin, pulmonary hypertension and hemorrhage, and pregnancy complications. Adequate screening is required to monitor for sequelae. First-line treatment is the monoclonal antibody eculizumab, but several organ systems may require specialized interventions and coordination of care with sub-specialists.

Clinical features and management of atypical hemolytic uremic syndrome patient with DGKE gene variants: a case report

Background

Atypical hemolytic uremic syndrome (aHUS) with diacylglycerol kinase epsilon (DGKE) gene variant is a rare variant of thrombotic microangiopathy (TMA). The information on the clinical features, management and long-term outcomes of DGKE-aHUS patients have not yet been fully elucidated. The aim of this study was to report a novel variant of the DGKE gene in a Chinese population with aHUS.

Case presentation

The present work reports a 7-month-old boy with aHUS, possibly triggered by gastrointestinal infection, without complement activation, with little response to plasma therapy and nephroprotective measures. The patient died during the 8th week of his hospital stay. The causes of death were intracranial hemorrhage and multiorgan dysfunction. Comprehensive WES of peripheral blood-derived DNA revealed two heterozygous variations in the DGKE exon region: NM_003647.2, c.610dup, p.Thr204Asnfs*4 and deletion of exons 4-6.

Conclusions

This case suggest that atypical HUS with DGKE gene variant has a poor prognosis with a high mortality rate, which typically manifests in the first year of life and presents as a systemic disease with early-onset HUS with rapidly worsening renal function and chronic proteinuria. There is no specific treatment for DGKE-aHUS. There have an uncertain benefit of plasma therapy for DGKE-aHUS patients. The literature demonstrated that anti-complement therapy showed benefits for DGKE-aHUS with complement activation and autoantibodies during the overt TMA presentation but did not prevent TMA relapses. Early diagnosis and treatment may prevent complications and improve prognosis.

PURTSCHER-LIKE RETINOPATHY ASSOCIATED WITH ATYPICAL HEMOLYTIC UREMIC SYNDROME: CASE REPORT AND REVIEW OF OUTCOMES

PURPOSE

The purpose of this study was to report the case of a patient presenting with newly diagnosed atypical hemolytic uremic syndrome (aHUS) and Purtscher-like retinopathy.

METHODS

This is an observational case report and review of literature. A 38-year-old woman presented with 3 months of rashes, fevers, arthralgias, and abdominal pain. Initial workup was suggestive of hypereosinophilic syndrome or adult-onset Still's disease. The patient developed acute renal failure and progressively blurry vision bilaterally over the course of 5 days. Funduscopic examination was notable for numerous Purtscher flecken and cotton-wool spots, with rare intraretinal hemorrhages at the posterior pole. The constellation of renal failure, hemolytic anemia, and thrombocytopenia prompted a workup for thrombotic microangiopathy that was remarkable for a mutation in the gene coding for complement protein C9.

RESULTS

The patient was diagnosed with aHUS and treated with intravenous pulse dose steroids for 3 days and an extended course of eculizumab. The patient's renal failure resolved, and her visual acuity improved, although she had residual visual field constriction and developed bilateral optic atrophy. Outcomes of other cases of Purtscher-like retinopathy related to aHUS are reviewed.

CONCLUSION

Purtscher-like retinopathy is a rare but severe ophthalmic complication of aHUS. Eculizumab is an effective treatment for the systemic illness caused by aHUS, and anatomical resolution of Purtscher-like retinopathy may follow, although visual prognosis remains guarded. Recovery of visual acuity may lag behind resolution of macular edema in these patients.

Can eculizumab be an option in traditional treatment-resistant ulcerative colitis?

Atypical/complement-mediated hemolytic uremic syndrome (A-HUS/CM-HUS) is a hereditary or sporadic disease with thrombotic microangiopathy (TMA). Diarrhea is a trigger that can cause attacks of CM-HUS. Although there are opinions that complement system activation plays a role in intestinal inflammation in patients with inflammatory bowel disease, the association of TMA with inflammatory bowel disease (IBD) has rarely been reported. In our case, a CM-HUS case that developed without an additional triggering factor in the course of ulcerative colitis (UC) was successfully treated with eculizumab, and then UC remission was also achieved. In this context, we would like to point out that the irregularities in the alternative pathway of the complement system may cause clinical findings in extra-renal organs, and the complement system may also play a role in the pathogenesis of inflammatory bowel disease. In addition, we think that our case may guide further studies on the usability of anti-complement therapies in treating patients with IBD who are resistant to conventional treatments.

Haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is a heterogeneous group of diseases that result in a common pathology, thrombotic microangiopathy, which is classically characterised by the triad of non-immune microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. In this Seminar, different causes of HUS are discussed, the most common being Shiga toxin-producing Escherichia coli HUS. Identifying the underlying thrombotic microangiopathy trigger can be challenging but is imperative if patients are to receive personalised disease-specific treatment. The quintessential example is complement-mediated HUS, which once carried an extremely high mortality but is now treated with anti-complement therapies with excellent long-term outcomes. Unfortunately, the high cost of anti-complement therapies all but precludes their use in low-income countries. For many other forms of HUS, targeted therapies are yet to be identified.

[Retinal tomography features of thrombotic microangiopathy associated with atypical hemolytic-uremic syndrome]

OBJECTIVE

To evaluate structural and morphological changes in the retina using optical coherence tomography (OCT) in patients with thrombotic microangiopathy (TMA) associated with atypical hemolytic-uremic syndrome (aHUS).

MATERIAL AND METHODS

The study analyzed OCT data of 14 patients (28 eyes) with an established diagnosis of aHUS including such indicators as central retinal thickness (CRT), thickness of the retinal nerve fiver layer (RNFL), ganglion cell layer (GCL), retinal pigment epithelium (RPE), etc.

RESULTS

Patients with aHUS were noted to have an increase in CRT, paracentral acute middle maculopathy in the form of a hyperreflective defect primarily of the inner nuclear layer of paracentral localization, as well as disorganization of the RPE, which was observed statistically significantly more often compared to healthy persons (p=0.0001, p=0.001 and p=0.009 respectively). In the subgroup with thrombotic retinopathy (6 people) a statistically significant increase in CRT and peripapillary RNFL was found (p=0.004 and p=0.001) compared to patients without thrombotic retinopathy, as well as the presence of paracentral acute middle maculopathy and transudative macular retinoschisis (p=0.0001 and p=0.004). A statistically significant thinning of the peripapillary RNFL was revealed (p=0.0001) in the subgroup with symptoms of Purtscher-like retinopathy (PLR) found retrospectively (4 people) compared to patients without retrospective PLR symptoms. A statistically significant decrease in CRT was revealed (p=0.018) in the subgroup of patients receiving systemic therapy with eculizumab (5 people) compared with patients not receiving this therapy. Statistically significant correlations were recorded between the studied OCT indicators, laboratory indicators, and the level of systolic blood pressure (p<0.05).

CONCLUSION

According to OCT, paracentral acute middle maculopathy is a biomarker of thrombotic retinopathy and the activity of systemic TMA associated with aHUS. Arterial hypertension is an additional aggravating factor in the development of paracentral acute middle maculopathy and transudative macular retinoschisis. Targeted therapy with eculizumab leads to an effective decrease in CRT, which is potentially associated with regression of ischemic edema. The outcome of PLR involves thinning of peripapillary RNFL.

Genetic variation in genes of inborn errors of immunity in children with unexplained encephalitis

Pediatric encephalitis has significant morbidity and mortality, yet 50% of cases are unexplained. Host genetics plays a role in encephalitis' development; however, the contributing variants are poorly understood. One child with anti-NMDA receptor encephalitis and ten with unexplained encephalitis underwent whole genome sequencing to identify rare candidate variants in genes known to cause monogenic immunologic and neurologic disorders, and polymorphisms associated with increased disease risk. Using the professional Human Genetic Mutation Database (Qiagen), we divided the candidate variants into three categories: monogenic deleterious or potentially deleterious variants (1) in a disease-consistent inheritance pattern; (2) in carrier states; and (3) disease-related polymorphisms. Six patients (55%) had a deleterious or potentially deleterious variant in a disease-consistent inheritance pattern, five (45%) were heterozygous carriers for an autosomal recessive condition, and six (55%) carried a disease-related polymorphism. Finally, seven (64%) had more than one variant, suggesting possible polygenetic risk. Among variants identified were those implicated in atypical hemolytic uremic syndrome, common variable immunodeficiency, hemophagocytic lymphohistiocytosis, and systemic lupus erythematosus. This preliminary study shows genetic variation related to inborn errors of immunity in acute pediatric encephalitis. Future research is needed to determine if these variants play a functional role in the development of unexplained encephalitis.

Concurrent cytomegalovirus enteritis and atypical hemolytic uremic syndrome with gastrointestinal tract involvement: a case report

Atypical hemolytic uremic syndrome (aHUS) is a rare disease caused by complement dysregulation that may involve the extra-renal system. Without appropriate prophylactic treatment, aHUS commonly recur after kidney transplantation (KT). In contrast, cytomegalovirus (CMV) infection is common in KT recipients and may affect various organ systems. Herein, we report a case of recurrent aHUS complicated by CMV enteritis. This 17-year-old KT recipient with aHUS having a CFH mutation was admitted to the hospital for gastric pain and vomiting. With worsening hemogram, recurrence of aHUS involving the gastrointestinal (GI) system was suspected. Upon treatment with anti-C5 antibody, the patient’s blood counts soon improved, but her GI symptoms did not. Esophagogastroduodenoscopy revealed multiple ulcers in the duodenum with pathologic findings consistent with aHUS and CMV enteritis; however, she did not have CMV antigenemia despite these findings. Treatment with ganciclovir resolved GI symptoms within 7 days. This case shows that recurrence of aHUS is often induced by intercurrent infection, and common infections after allograft transplantation, such as CMV, should always be suspected and confirmed for a proper treatment, particularly because CMV enteritis may not accompany CMV antigenemia.

Pediatric Atypical Hemolytic Uremic Syndrome Advances

Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by dysregulation of the alternate pathway. The diagnosis of aHUS is one of exclusion, which complicates its early detection and corresponding intervention to mitigate its high rate of mortality and associated morbidity. Heterozygous mutations in complement regulatory proteins linked to aHUS are not always phenotypically active, and may require a particular trigger for the disease to manifest. This list of triggers continues to expand as more data is aggregated, particularly centered around COVID-19 and pediatric vaccinations. Novel genetic mutations continue to be identified though advancements in technology as well as greater access to cohorts of interest, as in diacylglycerol kinase epsilon (DGKE). DGKE mutations associated with aHUS are the first non-complement regulatory proteins associated with the disease, drastically changing the established framework. Additional markers that are less understood, but continue to be acknowledged, include the unique autoantibodies to complement factor H and complement factor I which are pathogenic drivers in aHUS. Interventional therapeutics have undergone the most advancements, as pharmacokinetic and pharmacodynamic properties are modified as needed in addition to their as biosimilar counterparts. As data continues to be gathered in this field, future advancements will optimally decrease the mortality and morbidity of this disease in children.

[Ocular manifestations of primary thrombotic microangiopathy]

The article reviews literature on ocular manifestations of primary thrombotic microangiopathy. Thrombotic microangiopathy is a clinical and morphological syndrome that characterizes a systemic disseminated lesion of the microcirculatory bed, it is a special type of vascular damage that combines thrombosis and inflammation of the vascular wall leading to occlusion of the vessel lumen, causing ischemic damage to various organs and tissues. The classic types of primary thrombotic microangiopathy are thrombotic thrombocytopenic purpura, shigatoxin-associated hemolytic uremic syndrome (STEC-HUS) and atypical hemolytic uremic syndrome. Thrombotic thrombocytopenic purpura and atypical hemolytic uremic syndrome are characterized by ischemic damage to the visual organ as a result of suspected thrombotic microangiopathy in the microcirculatory bed of the eye. The clinical picture of ocular manifestations of these diseases is similar, however the damage to the eye in the form of ischemic Purtscher-like retinopathy is more characteristic of atypical hemolytic uremic syndrome, which may be due to chronic uncontrolled activation of the alternative complement pathway in this disorder. Timely initiation of systemic therapy of the underlying disease in most cases leads to complete restoration of visual functions. A thorough ophthalmological examination of patients with these diseases is required.

Atypical hemolytic uremic syndrome in the Colombian Caribbean: its particular characteristics

Introduction

Atypical hemolytic uremic syndrome (aHUS) is a rare and genetically mediated systemic disease most often caused by uncontrolled and chronic complement activation that leads to systemic thrombotic microangiopathy, renal and extra-renal damage.

Materials and methods

This is descriptive, retrospective and multicenter study, which reports demographic, clinical, laboratory, and genetic characteristics, as well as their treatment response and outcome of 20 aHUS patients diagnosed between 2014 and 2018.

Results

Most patients were female adults (75%) and 30% were associated to pregnancy/postpartum, 15% to autoimmune disease, and 65% to infections. Gastrointestinal involvement (75%) was the most frequent extra-renal organ damage. Antenatal mortality and mortality rate were 5% and 10%, respectively. 25% of the patients progressed to end-stage renal disease. In 4/8 of patients treated within 1 week of presentation, eculizumab treatment restored multi-organ function after 4 weeks of treatment. CFH (37%) and CFI (25%) mutations were the most frequent.

Conclusion

This is the first series of aHUS cases of Colombian Caribbean region which reports the clinical and epidemiological characteristics of this condition in this region.

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.

Thrombotic microangiopathy following aortic surgery with hypothermic circulatory arrest: a single-centre experience of an underestimated cause of acute renal failure

OBJECTIVES

Acute kidney injury (AKI) following surgery involving the heart-lung-machine is associated with high mortality and morbidity. In addition to the known mechanisms, thrombotic microangiopathy (TMA) triggered by the dysregulation of complement activation was recently described as another pathophysiological pathway for AKI following aortic surgery. The aim of this retrospective study was to analyse incidence, predictors and outcome in these patients.

METHODS

Between January 2018 and September 2019, consecutive patients undergoing aortic surgery requiring hypothermic circulatory arrest were retrospectively reviewed. If suspected, diagnostic algorithm was initiated to identify a TMA and its risk factors, and postoperative outcome parameters were comparably investigated.

RESULTS

The incidence of TMA in the analysed cohort (n = 247) was 4.5%. Multivariable logistic regression indicated female gender {odds ratio (OR) 4.905 [95% confidence interval (CI) 1.234-19.495], P = 0.024} and aortic valve replacement [OR 8.886 (95% CI 1.030-76.660), P = 0.047] as independent predictors of TMA, while cardiopulmonary bypass, X-clamp and hypothermic circulatory arrest times showed no statistically significance. TMA resulted in postoperative AKI (82%), neurological disorders (73%) and thrombocytopaenia [31 (interquartile range 25-42) G/l], corresponding to the diagnostic criteria. Operative mortality and morbidity were equal to patients without postoperative TMA, despite a higher incidence of re-exploration for bleeding (27 vs 6%; P = 0.027). After 6 months, survival, laboratory parameters and need for dialysis were comparable between the groups.

CONCLUSIONS

TMA is a potential differential diagnosis for the cause of AKI following aortic surgery regardless of the hypothermic circulatory arrest time. Timely diagnosis and appropriate treatment resulted in a comparable outcome concerning mortality and renal function.

Peripheral Ulcerative Keratitis Secondary to Atypical Hemolytic Uremic Syndrome

PURPOSE

To report a case of peripheral ulcerative keratitis secondary to atypical hemolytic uremic syndrome.

METHODS

We report the case of a 76-year-old man who presented with bilateral aggressive peripheral ulcerative keratitis. Clinical examinations and investigations are reported from the patients' admission.

RESULTS

The patient had an extended workup for autoimmune and infectious etiologies that all returned negative. The laboratory work in conjunction with renal biopsy and clinical symptoms were consistent with atypical hemolytic uremic syndrome. The patient was treated with systemic steroids for his peripheral ulcerative keratitis and underlying systemic disease. Corneal glueing and amniotic membrane grafting was also performed.

CONCLUSIONS

To our knowledge, we report the first known case of peripheral ulcerative keratitis secondary to atypical hemolytic uremic syndrome. In cases where the standard workup is negative, this diagnosis should be considered because it can have significant systemic morbidity.

Cerebral Microangiopathy in Two Dogs with Cutaneous and Renal Glomerular Vasculopathy

Cutaneous and renal glomerular vasculopathy (CRGV) is an emerging disease in the UK, but its aetiology remains unclear. It is considered a thrombotic microangiopathy (TMA) in which the kidney and skin are the most commonly affected organs. We now document two cases of CRGV with brain lesions, which may have accounted for neurological signs displayed by these animals. The histopathological brain lesions were similar to TMA lesions in humans with thrombotic thrombocytopaenic purpura (TTP) and complement-mediated haemolytic uraemic syndrome (CM-HUS), in which the neurological signs are more associated with TMA than with any systemic disease or electrolyte imbalance. Fibrinoid necrosis in brain arterioles and associated lesions in these dogs were similar to those in human CM-HUS, indicating that the alternative complement pathway may play an important role in the pathophysiology of CRGV.

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.

Renal Damage in Recurrent Atypical Hemolytic Uremic Syndrome Associated with C3 p.Ile1157Thr Gene Mutation

Patients with atypical hemolytic uremic syndrome (aHUS) associated with a C3 p.Ile1157Thr mutation show a relatively high renal survival and low mortality rates, but renal histopathological findings after recurrence have been rarely reported. A 30-year-old man with a C3 p.Ile1157Thr mutation experienced a third recurrence of thrombotic microangiopathies with neurological and gastrointestinal disorders. A renal biopsy performed during the recovery phase of acute kidney injury revealed collapsed glomeruli and arteriolar vacuolization. Approximately 10% of glomeruli were globally sclerotic, despite the absence of arterio-/arteriolo-sclerosis. These findings suggest substantial progression of irreversible injuries in multiple organs, including kidneys, which occurs in aHUS patients with repeated thrombotic microangiopathies.

Occlusive retinal vasculopathy with macular branch retinal artery occlusion as a leading sign of atypical hemolytic uremic syndrome - a case report

BACKGROUND

Hemolytic Uremic Syndrome (HUS) is a rare disorder characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure, considered within the group of thrombocytic microangiopathies. Ocular complications in HUS are very rare. Here, we report an adult patient who suffered from acute onset of paracentral scotoma, caused by branch retinal artery occlusion (BRAO), as a leading symptom of atypical HUS.

CASE PRESENTATION

A 39-year-old healthy male was lately diagnosed with essential hypertension and mild renal impairment. He complained about acute onset of central scotoma in his left eye. Fundus examination revealed marked narrowing of retinal vessels, cotton wool spots and few retinal hemorrhages in both eyes. The patient was diagnosed with bilateral ischemic retinal vasculopathy and acute macular BRAO in his left eye. Workup revealed thrombocytopenia, worsening renal failure. Renal biopsy showed signs of chronic thrombotic microangiopathy. The patient was diagnosed with atypical HUS (aHUS) and started on plasmapheresis, together with eculizumab. As his condition continued to worsen, he was put on renal replacement therapy. Due to a persistent monoclone of IgG1, the patient underwent bone marrow biopsy which revealed Monoclonal Gammopathy of renal significance, triggering a HUS and treatment was initiated accordingly. Two months after initial presentation, the patient developed neovascularization of the optic disc (NVD) in his left eye, and was treated with 3 monthly intravitreal bevacizumab injections with complete regression of the NVD. The patient suffered from myocardial infarction in the later course and was lost for follow-up. He returned 11 months after the last bevacizumab injection because of sudden loss of vision in his left eye caused by a dense vitreous hemorrhage. Biomicroscopy revealed a new NVD in his right eye. The patient underwent panretinal photocoagulation in both eyes with regression of neovascularization. Vision improved and remained 20/20 in both eyes.

CONCLUSION

We present a case report showing retinal ischemia can be linked with aHUS. As clinal diagnosis might be challenging, physicians should be aware of the rare ocular manifestations of this devastating multi-organ disease. In case of retinal ischemia, panretinal photocoagulation should be initiated soon to avoid blinding complications.

Clinicopathological features of cutaneous and renal glomerular vasculopathy in 178 dogs

BACKGROUND

One hundred seventy-eight dogs with cutaneous and renal glomerular vasculopathy (CRGV) were evaluated to further the understanding of the natural course of CRGV. CRGV, a form of thrombotic microangiopathy, can cause skin lesions and potentially acute kidney injury (AKI) with a high mortality rate.

METHODS

Cases were submitted from multiple practices from 2012 until June 2019. Clinical histories and laboratory data were reviewed to describe the features of CRGV.

RESULTS

Most cases (91%) occurred between November and May. Fifteen dogs (8.4%) with CRGV were in contact with another dog that developed skin lesions +/- AKI. Limb lesions were present on 144 dogs (80.9%) at presentation. Median time from appearance of a lesion to AKI was 3 days (range -4-45 days). Neurological signs occurred in 33 dogs (18.6%) including at presentation in 2 (1.1%). Systemic signs were present in 13 dogs prior to a skin lesion (7.3%). Non-steroidal anti-inflammatory drugs were prescribed prior to AKI identification in 92 of 170 dogs (54.1%). Thrombocytopenia was present in 115 of 137 (83.9%) of dogs.

CONCLUSION

The timeframe over which AKI may develop is longer than previously reported, neurological signs can be identified at presentation or during hospitalisation, and thrombocytopenia is even more common than previously reported.

Utilization Pattern for Eculizumab Among Children With Hemolytic Uremic Syndrome

Background: Hemolytic uremic syndrome (HUS) is a complex disease with multi-organ involvement. Eculizumab therapy is recommended for treatment of complement mediated hemolytic uremic syndrome (cHUS). However, there are few studies evaluating eculizumab therapy among children with HUS. The primary objectives of the study were to describe and identify factors associated with eculizumab therapy in children with HUS. Design/Methods: This large, retrospective, multi-center, cohort study used the Pediatric Health Information System (PHIS) database to identify the index HUS-related hospitalization among patients ≤18 years of age from September 23, 2011 (Food and Drug Administration approval date of eculizumab) through December 31, 2018. Multivariate analysis was used to identify independent factors associated with eculizumab therapy during or after the index hospitalization. Results: Among 1,885 children included in the study, eculizumab therapy was noted in 167 children with a median age of 3.99 years (SD ± 4.7 years). Eculizumab therapy was administered early (within the first 7 days of hospitalization) among 65% of children who received the drug. Mortality during the index hospitalization among children with eculizumab therapy was 4.2 vs. 3.0% without eculizumab therapy (p = 0.309). Clinical factors independently associated with eculizumab therapy were encephalopathy [odds ratio (OR) = 3.09; p ≤ 0.001], seizure disorder (OR = 2.37; p = 0.006), and cardiac involvement (OR = 6.36, p < 0.001). Conclusion(s): Only 8.9% of children received eculizumab therapy. Children who presented with neurological and cardiac involvement with severe disease were more likely to receive eculizumab therapy, and children who received therapy received it early during their index hospitalization. Further prospective studies are suggested to confirm these findings.

The long-acting C5 inhibitor, ravulizumab, is effective and safe in pediatric patients with atypical hemolytic uremic syndrome naïve to complement inhibitor treatment

Ravulizumab, a long-acting complement C5 inhibitor engineered from eculizumab, allows extending maintenance dosing from every 2-3 weeks to every 4-8 weeks depending on bodyweight. Here, we evaluated the efficacy and safety of ravulizumab in complement inhibitor-naïve children (under 18 years) with atypical hemolytic uremic syndrome. In this phase III, single-arm trial, ravulizumab was administered every eight weeks in patients 20 kg and over, and four weeks in patients under 20 kg. The primary endpoint was a complete thrombotic microangiopathy response (normalization of platelet count and lactate dehydrogenase, and a 25% or more improvement in serum creatinine) through 26 weeks. Secondary endpoints included change in hematologic parameters and kidney function. 18 patients with a median age of 5.2 years were evaluated. At baseline, symptoms of atypical hemolytic uremic syndrome outside the kidney were present in 72.2% of patients and 38.9% had been in intensive care. Baseline estimated glomerular filtration rate was 22 mL/min/1.73 m². By week 26, 77.8% of patients achieved a complete thrombotic microangiopathy response; 94.4%, 88.9% and 83.3% of patients achieved platelet normalization, lactate dehydrogenase normalization and a 25% or more improvement in serum creatinine, respectively. By week 50, 94.4% patients had achieved a complete thrombotic microangiopathy response. Median improvement in platelet count was 246 and 213 x10⁹/L through week 26 and week 50, respectively. The median increase above baseline in estimated glomerular filtration rate was 80 and 94 mL/min/1.73m² through week 26 and week 50, respectively. No unexpected adverse events, deaths, or meningococcal infections occurred. Thus, ravulizumab rapidly improved hematologic and kidney parameters with no unexpected safety concerns in complement inhibitor-naïve children with atypical hemolytic uremic syndrome.

Revisiting the role of factor H in age-related macular degeneration: Insights from complement-mediated renal disease and rare genetic variants

Ophthalmologists are long familiar with the eye showing signs of systemic disease, but the association between age-related macular degeneration and abnormal complement activation, common to several renal disorders, has only recently been elucidated. Although complement activation products were identified in drusen almost three decades ago, it was not until the early 21st century that a single-nucleotide polymorphism in the complement factor H gene was identified as a major heritable determinant of age-related macular degeneration, galvanizing global efforts to unravel the pathogenesis of this common disease. Advances in proteomic analyses and familial aggregation studies have revealed distinctive clinical phenotypes segregated by the functional effects of common and rare genetic variants on the mature protein and its splice variant, factor H-like protein 1. The predominance of loss-of-function, N-terminal mutations implicate age-related macular degeneration as a disease of general complement dysregulation, offering several therapeutic avenues for its modulation. Here, we explore the molecular impact of these mutations/polymorphisms on the ability of variant factor H/factor H-like protein 1 to localize to polyanions, pentraxins, proinflammatory triggers, and cell surfaces across ocular and renal tissues and exert its multimodal regulatory functions and their clinical implications. Finally, we critically evaluate key therapeutic and diagnostic efforts in this rapidly evolving field.

Hypertensive choroidopathy in atypical hemolytic-uremic syndrome

PURPOSE

We present the case of a 22-year-old woman, diagnosed as having atypical hemolytic uremic syndrome with a hypertensive crisis, who presented a bilateral serous retinal detachment.

CASE DESCRIPTION

A 22-year-old woman, diagnosed as having atypical hemolytic uremic syndrome, was referred for blurred vision in both eyes, evolving over 7 days. Treatment including hemodialysis, plasma exchange, systemic steroids, antihypertensive medications and eculizumab was started 1 month prior to referral. At presentation, best-corrected visual acuity was 20/40 in the right eye and 20/25 in the left eye. Retinal examination revealed bilateral serous retinal detachment in the posterior pole and some small, flat, variably pigmented lesions. Optical coherence tomography confirmed marked serous retinal detachment in both eyes. Fluorescein and indocyanine green angiography was performed. Treatment for systemic hypertension was changed. Seven days later, dilated fundus examination and optical coherence tomography demonstrated a significant regression of the serous retinal detachment. Her visual acuity improves in both eyes at the last control, showing at fundus examination a complete resolution of the exudative detachment but a persistence of variable flat pigmented lesion.

CONCLUSION

Although multiple organ systems are commonly affected in hemolytic uremic syndrome, ocular involvement has only been described in very few cases. Ocular manifestations in atypical hemolytic uremic syndrome include retinal, choroidal and vitreal hemorrhages, retina and/or ischemic signs. Bilateral serous retinal detachment may also be a sign of atypical hemolytic uremic syndrome or even the first manifestation of a hypertensive event.

Hemolytic uremic syndrome: differential diagnosis with the onset of inflammatory bowel diseases

BACKGROUND

Shiga-toxin Escherichia coli productor (STEC) provokes frequently an important intestinal damage that may be considered in differential diagnosis with the onset of Inflammatory Bowel Disease (IBD). The aim of this work is to review in the current literature about Hemolytic Uremic Syndrome (HUS) and IBD symptoms at the onset, comparing the clinical presentation and symptoms, as the timing of diagnosis and of the correct treatment of both these conditions is a fundamental prognostic factor. A focus is made about the association between typical or atypical HUS and IBD and a possible renal involvement in patient with IBD (IgA-nephropathy).

METHODS

A systematic review of scientific articles was performed consulting the databases PubMed, Medline, Google Scholar, and consulting most recent textbooks of Pediatric Nephrology.

RESULTS

In STEC-associated HUS, that accounts for 90% of cases of HUS in children, the microangiopathic manifestations are usually preceded by gastrointestinal symptoms. Initial presentation may be considered in differential diagnosis with IBD onset. The transverse and ascending colon are the segments most commonly affected, but any area from the esophagus to the perianal area can be involved. The more serious manifestations include severe hemorrhagic colitis, bowel necrosis and perforation, rectal prolapse, peritonitis and intussusception. Severe gastrointestinal involvement may result in life-threatening complications as toxic megacolon and transmural necrosis of the colon with perforation, as in Ulcerative Colitis (UC). Transmural necrosis of the colon may lead to subsequent colonic stricture, as in Crohn Disease (CD). Perianal lesions and strictures are described. In some studies, intestinal biopsies were performed to exclude IBD. Elevation of pancreatic enzymes is common. Liver damage and cholecystitis are other described complications. There is no specific form of therapy for STEC HUS, but appropriate fluid and electrolyte management (better hyperhydration when possible), avoiding antidiarrheal drugs, and possibly avoiding antibiotic therapy, are recommended as the best practice. In atypical HUS (aHUS) gastrointestinal manifestation are rare, but recently a study evidenced that gastrointestinal complications are common in aHUS in presence of factor-H autoantibodies. Some report of patients with IBD and contemporary atypical-HUS were found, both for CD and UC. The authors conclude that deregulation of the alternative complement pathway may manifest in other organs besides the kidney. Finally, searching for STEC-infection, or broadly for Escherichia coli (E. coli) infection, and IBD onset, some reviews suggest a possible role of adherent invasive E. coli (AIEC) on the pathogenesis of IBD.

CONCLUSIONS

The current literature shows that gastrointestinal complications of HUS are quite exclusive of STEC-associated HUS, whereas aHUS have usually mild or absent intestinal involvement. Severe presentation as toxic megacolon, perforation, ulcerative colitis, peritonitis is similar to IBD at the onset. Moreover, some types of E. coli (AIEC) have been considered a risk factor for IBD. Recent literature on aHUS shows that intestinal complications are more common than described before, particularly for patients with anti-H factor antibodies. Moreover, we found some report of patient with both aHUS and IBD, who benefit from anti-C5 antibodies injection (Eculizumab).