Kidney Thrombotic Microangiopathy After COVID-19 Associated With C3 Gene Mutation

Coronavirus disease 2019-associated thrombotic microangiopathy treated with plasma exchange and antihypertensive therapy in a patient with HIV: A case report with literature review

RATIONALE

Coronavirus disease 2019 (COVID-19) is an infectious disease that often causes complications in multiple organs and thrombosis due to abnormal blood coagulation. This case report aimed to describe the clinical course of COVID-19-associated thrombotic microangiopathy (TMA) and reviewed the comprehensive information on TMA, thrombotic thrombocytopenic purpura (TTP), and atypical hemolytic uremic syndrome associated with COVID-19 in the past literature.

PATIENT CONCERNS

A 46-year-old Japanese man was diagnosed with human immunodeficiency virus infection 10 years ago and treated with antiretroviral therapy. The patient presented with fever, malaise, hematuria, and bilateral upper abdominal discomfort for the past 4 days.

DIAGNOSES

COVID-19-associated TMA was diagnosed based on a positive polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 and laboratory findings such as thrombocytopenia, acute kidney injury, and hemolytic anemia. Malignant hypertension and human immunodeficiency virus infection were also considered as differential diagnoses of TMA.

INTERVENTIONS

Considering the possibility of TTP, plasma exchange was performed, and glucocorticoids were administered. Hemodialysis was performed for acute kidney injury. Antihypertensive drugs were administered to control the high blood pressure.

OUTCOMES

Platelet count and renal function improved, and hemodialysis was no longer required. The patient was in good general condition and was discharged from the hospital.

LESSONS

COVID-19-associated TMA should be considered as a differential diagnosis during the COVID-19 epidemic. Excessive inflammation and severe COVID-19 are not essential for TMA development. Early intervention using conventional TMA treatments, such as plasma exchange and corticosteroids, might be important in improving prognosis while differentiating between TTP and atypical hemolytic uremic syndrome. Antihypertensive therapy may be helpful in the treatment of COVID-19-associated TMA.

Complement-Mediated Thrombotic Microangiopathy Related to COVID-19 or SARS-CoV-2 Vaccination

Introduction

Infectious diseases and vaccinations are trigger factors for thrombotic microangiopathy. Consequently, the COVID-19 pandemic could have an effect on disease manifestation or relapse in patients with atypical hemolytic syndrome/complement-mediated thrombotic microangiopathy (aHUS/cTMA).

Methods

We employed the Vienna TMA cohort database to examine the incidence of COVID-19 related and of SARS-CoV-2 vaccination-related relapse of aHUS/cTMA among patients previously diagnosed with aHUS/cTMA during the first 2.5 years of the COVID-19 pandemic. We calculated incidence rates, including respective confidence intervals (CIs) and used Cox proportional hazard models for comparison of aHUS/cTMA episodes following infection or vaccination.

Results

Among 27 patients with aHUS/cTMA, 13 infections triggered 3 (23%) TMA episodes, whereas 70 vaccinations triggered 1 TMA episode (1%; odds ratio 0.04; 95% CI 0.003-0.37, P = 0.01). In total, the incidence of TMA after COVID-19 or SARS-CoV-2 vaccination was 6 cases per 100 patient years (95% CI 0.017-0.164) (4.5/100 patient years for COVID-19 and 1.5/100 patient years for SARS-CoV-2 vaccination). The mean follow-up time was 2.31 ± 0.26 years (total amount: 22,118 days; 62.5 years) to either the end of the follow-up or TMA relapse (outcome). Between 2012 and 2022 we did not find a significant increase in the incidence of aHUS/cTMA.

Conclusion

COVID-19 is associated with a higher risk for aHUS/cTMA recurrence when compared to SARS-CoV-2 vaccination. Overall, the incidence of aHUS/cTMA after COVID-19 infection or SARS-CoV-2 vaccination is low and comparable to that described in the literature.

Pitfalls of Thrombotic Microangiopathies in Children: Two Case Reports and Literature Review

Thrombotic microangiopathy can present itself in the form of several clinical entities, representing a real challenge for diagnosis and treatment in pediatric practice. Our article aims to explore the evolution of two rare cases of pediatric thrombotic thrombocytopenic purpura (TTP) and atypical hemolytic uremic syndrome (aHUS) with extremely similar clinical pictures, which, coincidentally, presented at approximately the same time in our hospital. These cases and our literature review demonstrate the multiple facets of thrombotic microangiopathy, which can produce various determinations and salient manifestations even among the pediatric population. TTP and aHUS may represent genuine diagnostic pitfalls through the overlap of their clinical and biological findings, although they develop through fundamentally different mechanisms that require different therapeutic approaches. As a novelty, we underline that COVID-19 infection cannot be excluded as potential trigger for TTP and aHUS in our patients and we predict that other reports of such an association will follow, raising a complex question of COVID-19's implication in the occurrence and evolution of thrombotic microangiopathies. On this matter, we conducted literature research that resulted in 15 cases of COVID-19 pediatric infections associated with either TTP or aHUS. Taking into consideration the morbidity associated with TTP and aHUS, an elaborate differential diagnosis and prompt intervention are of the essence.

Thrombocytopenia and clinical outcomes among patients with COVID-19 disease: A cohort study

Background and Aims

Thrombocytopenia is increasingly recognized among patients with critical illness and plays a role in several diseases affecting different organ systems. Therefore, we studied the prevalence of thrombocytopenia among hospitalized COVID-19 patients and its correlation with disease severity and clinical outcomes.

Methods

This was an observational retrospective cohort study conducted on 256 hospitalized COVID-19 patients. Thrombocytopenia is defined as a platelet count below 150,000/μL. Disease severity was classified based on the five-point CXR scoring tool.

Results

Thrombocytopenia was found in 66 (25.78%) patients. In outcomes, 41 (16%) patients were admitted to intensive care unit, 51 (19.9%) died, and 50 (19.5%) had acute kidney injury (AKI). Of the total patients with thrombocytopenia, 58 (87.9%) had early thrombocytopenia, while 8 (12.1%) had late thrombocytopenia. Notably, mean survival time was markedly decreased in late-onset thrombocytopenia cases (p < 0.0001). Patients with thrombocytopenia showed a significant increase in creatinine compared to those with normal platelet counts (p < 0.05). Moreover, thrombocytopenia was more prevalent in patients with chronic kidney disease compared to other comorbidities (p < 0.05). In addition, hemoglobin was significantly lower in the thrombocytopenia group (p < 0.05).

Conclusion

Thrombocytopenia is a common finding among COVID-19 patients, with a predilection toward a specific group of patients, though the exact reasons are unclear. It predicts poor clinical outcomes and is closely linked to mortality, AKI, and the need for mechanical ventilation. These findings suggest that more research is required to study the mechanism of thrombocytopenia and the possibility of thrombotic microangiopathy in COVID-19 patients.

Coronavirus Disease 2019-Associated Thrombotic Microangiopathy: Literature Review

Coronavirus disease 2019 (COVID-19) can lead to clinically significant multisystem disorders that also affect the kidney. According to recent data, renal injury in the form of thrombotic microangiopathy (TMA) in native kidneys ranks third in frequency. Our review of global literature revealed 46 cases of TMA in association with COVID-19. Among identified cases, 18 patients presented as thrombotic thrombocytopenic purpura (TTP) and 28 cases presented as atypical hemolytic uremic syndrome (aHUS). Altogether, seven patients with aHUS had previously proven pathogenic or likely pathogenic genetic complement abnormalities. TMA occurred at the time of viremia or even after viral clearance. Infection with COVID-19 resulted in almost no or only mild respiratory symptoms in the majority of patients, while digestive symptoms occurred in almost one-third of patients. Regarding the clinical presentation of COVID-19-associated TMA, the cases showed no major deviations from the known presentation. Patients with TTP were treated with plasma exchange (88.9%) or fresh frozen plasma (11.1%), corticosteroids (88.9%), rituximab (38.9%), and caplacizumab (11.1%). Furthermore, 53.6% of patients with aHUS underwent plasma exchange with or without steroid as initial therapy, and 57.1% of patients received a C5 complement inhibitor. Mortality in the studied cohort was 16.7% for patients with TTP and 10.7% for patients with aHUS. The exact role of COVID-19 in the setting of COVID-19-associated TMA remains unclear. COVID-19 likely represents a second hit of aHUS or TTP that manifests in genetically predisposed individuals. Early identification of the TMA subtype and appropriate prompt and specific treatment could lead to good outcomes comparable to survival and recovery statistics for TMA of all causes.

COVID-19: a trigger for severe thrombotic microangiopathy in a patient with complement gene variant

The evidence regarding thrombotic microangiopathy (TMA) related to Coronavirus Infectious Disease 2019 (COVID-19) in patients with complement gene mutations as a cause of acute kidney injury (AKI) are limited. We presented the case of a 23-year-old male patient admitted with an asymptomatic form of COVID-19, but with uncontrolled hypertension and AKI. Kidney biopsy showed severe lesions of TMA. In evolution patient had persistent microangiopathic hemolytic anemia, decreased level of haptoglobin and increased LDH level. Decreased complement C3 level and the presence of schistocytes were found for the first time after biopsy. Kidney function progressively decreased and the patient remained hemodialysis dependent. Complement work-up showed a heterozygous variant with unknown significance in complement factor I (CFI) c.-13G>A, affecting the 5' UTR region of the gene. In addition, the patient was found to be heterozygous for the complement factor H (CFH) H3 haplotype (involving the rare alleles of c.-331C>T, Q672Q and E936D polymorphisms) reported as a risk factor of atypical hemolytic uremic syndrome. This case of AKI associated with severe TMA and secondary hemolytic uremic syndrome highlights the importance of genetic risk modifiers in the alternative pathway dysregulation of the complement in the setting of COVID-19, even in asymptomatic forms.

Case Report: Tackling Complement Hyperactivation With Eculizumab in Atypical Hemolytic Uremic Syndrome Triggered by COVID-19

Hemolytic uremic syndrome (HUS) is a rare life-threatening disease of unrestrained complement system dysregulation, microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure in genetically predisposed individuals. In this report, we describe two cases of SARS-CoV-2–associated HUS treated with eculizumab, a C5-blocking monoclonal antibody reported to be remarkably effective in the treatment of HUS. Detailed biochemical and genetic complement system analysis is reported, and the prompt clinical response after C5 pharmacological blockade is documented. Our report provides the rationale and supports the use of terminal complement pathway inhibition for the treatment of SARS-CoV-2–associated HUS.

The state of complement in COVID-19

Hyperactivation of the complement and coagulation systems is recognized as part of the clinical syndrome of COVID-19. Here we review systemic complement activation and local complement activation in response to the causative virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and their currently known relationships to hyperinflammation and thrombosis. We also provide an update on early clinical findings and emerging clinical trial evidence that suggest potential therapeutic benefit of complement inhibition in severe COVID-19.

Anti-factor H antibody associated hemolytic uremic syndrome following SARS-CoV-2 infection

BACKGROUND

The pathogenesis of autoantibody generation in anti-factor H (FH) antibody associated atypical hemolytic uremic syndrome (aHUS) is unknown and is perhaps triggered by an infectious or environmental agent. We observed an unusual increase of patients with anti-FH antibody associated aHUS coinciding with the second pandemic wave in New Delhi and suspected that SARS-CoV-2 infection might be a potential trigger.

METHODS

We screened for SARS-CoV-2 infection using reverse transcriptase polymerase chain reaction (RT-PCR) and serology in 13 consecutive patients with anti-FH antibody associated aHUS during the past year in New Delhi.

RESULTS

We report 5 patients, 4-13 years old, who presented with a febrile illness without respiratory symptoms during the second pandemic wave. Of these, 3 patients presented with a relapse 25-85 months following the initial episode of aHUS. SARS-CoV-2 was detected by RT-PCR in 1 patient and by serology in 4 patients (median titer 47.1 cut-off index). Patients had high titers of anti-FH antibodies (median 2,300 AU/ml). Genetic studies, done in 3 of the 5 patients, showed homozygous CFHR1 deletion without other significant genetic abnormalities. Specific management comprised plasma exchanges and oral prednisolone, combined with either cyclophosphamide or mycophenolate mofetil. At median follow-up of 3.3 months, the estimated glomerular filtration rate in 4 patients ranged from 62 to 110 ml/min/1.73 m²; one patient was dialysis-dependent.

CONCLUSION

Increased vigilance is required during the pandemic, especially in patients with anti-FH associated aHUS, who might relapse despite quiescent disease for a prolonged period. A higher resolution version of the Graphical abstract is available as Supplementary information.

Case report: Diarrhea-associated hemolytic uremic syndrome in the Era of COVID-19

Over the past two years, a growing number of SARS-CoV-2 infection-associated clinical pediatric phenotypes have been identified, including a hemolytic uremic syndrome (HUS) form of thrombotic microangiopathy. Oregon's high prevalence of Shiga toxin-producing Escherichia coli (STEC) infections gives it a unique perspective to discuss the impact of COVID-19 and HUS. We seek to highlight SARS-CoV-2 as a potential new infectious etiology of severe diarrhea-associated HUS, based on two cases from Portland, Oregon, occurring in non-COVID-19 immunized children. The first case is a previously healthy ten-year-old who presented with SARS-CoV-2 infection and bloody diarrhea after an appendectomy, followed by full-blown oligo-anuric HUS. Second is a previously healthy six-year-old who presented with short-lived bloody diarrhea, rapidly evolving to HUS, and who tested positive for COVID-19 via polymerase chain reaction and STEC toxins one and two. These two cases highlight two main points. First, SARS-CoV-2 must be included in the differential diagnosis of diarrhea-associated HUS, either as the sole agent or concurrent with a STEC infection. Second, when managing STEC gastroenteritis the recommendation has been to maintain excellent hydration as a strategy to prevent the progression to oligo-anuric acute kidney injury and HUS. This strategy may need to be re-evaluated in a patient with SARS-CoV-2 infection or co-infection.

Atypical HUS triggered by COVID-19: A case report

We hereby present a case of an atypical hemolytic uremic syndrome (aHUS) precipitated by coronavirus disease 2019 (COVID-19). A 26-year-old male was diagnosed with COVID-19 and acute kidney injury. His kidney biopsy was suggestive of thrombotic microangiopathy. Five sessions of plasmapheresis were done but were discontinued in view of nonrecovery of kidney function. He was then referred for a kidney transplant. On genetic analysis, he was found to have mutations in the complement system (CFHR1 and CFHR3), which suggested this was a case of aHUS precipitated by COVID-19. In view of the high risk of recurrence of the primary disease in live-related kidney donor transplantation, he was advised for simultaneous liver and kidney transplants.