NEW INSIGHTS ON EPIDEMIOLOGICAL DATA AND IMPACT OF THE COVID-19 PANDEMIC ON IGA VASCULITIS IN CHILDREN AND ADULTS IN FRANCE: A NATIONWIDE COHORT

BackgroundIgA vasculitis (IgAV) is a rare autoimmune disease affecting small vessels. It is well established that the incidence is higher in children (3 to 26 per 100,000 children/year,) [1] than in adults (0.1 to 1.8 per 100,000 individuals/year) [1]. However others epidemiological data and impact of the COVID-19 on IgAV remain overlooked [2].ObjectivesTo collect and analyze epidemiological data on IgAV in both adults and children in France.MethodsWe conducted an observational study using a national database called "BNDMR” [3] (Banque Nationale de Données Maladies Rares) on IgA vasculitis (code ORPHA761), which gathered patients managed in the French rare disease expert network. The incidence was estimated from the date of diagnosis, and we calculated the median annual incidence over the period 2010-2022. We specifically assessed the north/south gradient (latitude of the residence higher/lower than the median of the latitudes), the seasonality, and the impact of the COVID-19 pandemic compared to other patients reported within the same period and addressed in the same expert centers used as controls.ResultsDuring this 12-year period, 1988 patients with IgAV were reported (1498 children;490 adults). The male to female ratio was 1.57 for adults and 1.05 for children. The median IgAV annual incidence was 15 cases/year [IQR 9-30] and 82 cases/year [IQR 72-86] for adult and children cases respectively. Time to diagnosis was less than 1 month for both. Compared with other patients reported in the same expert centers, IgAV was more frequently reported in the southern part of France than in the north (OR 4.88 [95% confidence intervals: 4.17 - 5.74] in adults and OR 1.51 [1.35 - 1.68] in children). IgAV was also more frequently observed in winter than during the rest of the year in both adults (OR 1.60 [1.39 - 1.82]) and children (OR 1.22 [1.01 - 1.48]). The incidence of IgAV decreased during the COVID-19 pandemic period (from March 2020 to September 2022) in children (OR 0.62 [0.47 - 0.81]) but not in the adult population (OR 0.90 [0.76 - 1.06]).ConclusionOur study confirms the winter seasonality and sex ratio in IgAV [4,5], but suggests that the incidence or the reporting of IgAV decreased in children during the COVID19 pandemia, possibly due to barrier measures [6]. The observed north/south gradient need confirmation. The main limitation of this study is a possible IgAV under-reporting as this study rely only on cases addressed in expert centers.References[1]Audemard-Verger A, Pillebout E, Guillevin L, Thervet E, Terrier B. IgA vasculitis (Henoch-Shönlein purpura) in adults: Diagnostic and therapeutic aspects. Autoimmun Rev. 2015;14(7):579-585. doi:10.1016/j.autrev.2015.02.003[2]Deshayes S, Moulis G, Pillebout E, Aouba A, Audemard-Verger A. Positive predictive value of hospital discharge diagnosis code to identify immunoglobulin A vasculitis in France: A validation study. Eur J Intern Med. 2017;43:e18-e19. doi:10.1016/j.ejim.2017.05.025[3]Jannot AS, Messiaen C, Khatim A, Pichon T, Sandrin A, BNDMR infrastructure team. The ongoing French BaMaRa-BNDMR cohort: implementation and deployment of a nationwide information system on rare disease. J Am Med Inform Assoc. 2022;29(3):553-558. doi:10.1093/jamia/ocab237[4]Piram M, Maldini C, Biscardi S, et al. Incidence of IgA vasculitis in children estimated by four-source capture-recapture analysis: a population-based study. Rheumatology (Oxford). 2017;56(8):1358-1366. doi:10.1093/rheumatology/kex158[5]Gardner-Medwin JMM, Dolezalova P, Cummins C, Southwood TR. Incidence of Henoch-Schönlein purpura, Kawasaki disease, and rare vasculitides in children of different ethnic origins. Lancet. 2002;360(9341):1197-1202. doi:10.1016/S0140-6736(02)11279-7[6]Kaya Akca U, Atalay E, Cuceoglu MK, et al. Impact of the COVID-19 pandemic on the frequency of the pediatric rheumatic diseases. Rheumatol Int. 2022;42(1):51-57. doi:10.1007/s00296-021-05027-7Figure.Acknowledgements:NIL.Disclosure of InterestsNone Declared.

Blood Transfusion in Covid-19 Patients: One Year Survey

Introduction: Due to the COVID-19 outbreak, many chronic patients and elective surgical procedures have been postponed to create spaces for the hospitalization of COVID-19 patients, raising issues related to this change. The objective of this study is to assess the effect of the COVID-19 pandemic on the demand for blood products transfusion. Materials ant methods: The study presents the results of a retrospective study of blood transfusions in COVID-19 patients admitted to the Constanta County Emergency Clinical Hospital. The period of study was January-December 2021. We compared the transfusion requirement for each type of blood component in COVID 19 patients versus patients with non-COVID pathology. Results and discussions: During 2021, we transfused 282 COVID-19 patients;150 patients had only Covid pneumonia (of which 19 patients with severe forms needed intensive care in ICU-Covid), and 132 patients had various co-morbidities. The maximum blood requests was registered in the period February - April 2021, with a peak of 63 patients in April 2021. The main co-morbidities in patients with Covid 19 were: severe anemia in patients with malignant hemopathies. Anemia at admission in patients with Covid pneumonia is reported in more than 40% of patients. Moderate anemia (Hb <11 g/dL) is considered as an independent risk factor for the severe course of COVID-19 infection and mortality in these patients. The transfusion requirement in these patients was greater than 1.43 RBC (units/patient), 0.81 Plasma units/patient, 0.40 Platelets concentrate units + single donor platelet concentrate units/patient, in accordance with the associated pathology. Conclusion(s): The most requested product was packed red blood cells, the correction of anaemia being an important factor in preventing the severe course of the disease. The platelet requirement was 0.15 units/patient, thrombocytopenia being present in patients with severe evolution of the infection (hospitalized in ICU-COVID). The most requested blood groups were O+ and A+. COVID-19 transfusion data will help plan and prepare for the use of blood resources during the pandemic.Copyright © 2022 Sevigean Ali et al., published by Sciendo.

Case report: COVID-19-associated refractory thrombotic thrombocytopenic purpura complicated with Guillain-Barré syndrome.

Thrombotic thrombocytopenic purpura (TTP), a rare and lethal thrombotic microangiopathy, is an autoimmune disease that can be triggered by viral infections such as COVID-19. This condition is characterized by hemolytic microangiopathy, thrombocytopenia, and neurologic alterations, possibly accompanied by fever and renal damage. Moreover, more than 220 patients with Guillain-Barré syndrome (GBS) have been reported in association with the COVID-19 infection. In this report, we present a case of a patient who developed refractory TTP complicated by GBS following a SARS-CoV-2 infection. We aimed to highlight the importance of accurately diagnosing neurological complications associated with a COVID-19 infection and to demonstrate our strategies for treating a patient with COVID-19 infection-related refractory TTP complicated by GBS.

Erratum: Immune-mediated thrombotic thrombocytopenic purpura following mRNA-based COVID-19 vaccine BNT162b2: Case report and mini-review of the literature.

[This corrects the article DOI: 10.3389/fmed.2022.890661.].

IgA Vasculitis Following COVID-19 Vaccination.

IgA vasculitis is generally triggered by infectious causes, but it has also been reported after immunization with various vaccines. Herein, we report two cases of IgA vasculitis after receiving the first or second dose of the Pfizer-BioNTech BNT16B2b2 mRNA vaccine. Two men, aged 22 and 30 years, developed palpable purpura on the extremities and arthritis. One patient also complained of fever and gastrointestinal symptoms. Laboratory findings revealed mild leukocytosis and slightly elevated C-reactive protein level, although platelet count and coagulation profile were within normal levels in both cases. Proteinuria and microhematuria were seen in one patient. Skin biopsies were performed in both patients and revealed leukocytoclastic vasculitis. The deposit of IgA and C3 was shown on immunofluorescence studies in one patient. Both patients were diagnosed with IgA vasculitis and treated with prednisolone, and their symptoms resolved within 1 week after initiation of treatment. The COVID-19 mRNA vaccine could trigger IgA vasculitis; however, a coincidence cannot be ruled out.

IgA Vasculitis Associated With COVID-19.

IgA vasculitis, also known as Henoch-Schonlein Purpura (HSP), is an inflammatory disorder of small blood vessels that can present with palpable purpura, arthralgias, abdominal pain, and kidney disease. It is most commonly found in pediatric patients after an inciting infection but has been seen across all ages and associated with certain drugs and vaccines. COVID-19 has been associated with various cutaneous manifestations, but HSP is a rarely reported one. We present a case of a 21-year-old female presenting with a petechial rash found to be seronegative IgA vasculitis presenting concurrently with dyspnea secondary to COVID-19. She was initially seen by an outside practitioner, tested negative for COVID, and was prescribed a course of oral prednisone. Shortly thereafter, she visited the ED for worsening shortness of breath and tested positive for COVID-19, for which she received Paxlovid. Biopsy after a visit to a dermatologist confirmed intramural IgA deposition on immunofluorescence, and she was tapered off prednisone and started on azathioprine.

Diabetic Ketoacidosis Complicated by Thrombotic Thrombocytopenic Purpura: A Rare Association.

Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially life-threatening blood disorder caused by a deficiency or dysfunction of ADAMTS13 and can occur secondary to various conditions, including autoimmune diseases, infections, medications, pregnancy, and malignancies. Diabetic ketoacidosis (DKA) inducing TTP is uncommon and not widely reported in the literature. Herein, we report a case of TTP induced by DKA in an adult patient. His clinical picture, serological, and biochemical results confirmed the diagnosis of TTP induced by DKA, and his clinical course did not improve despite normalization of glucose level, plasmapheresis, and aggressive management. Our case report emphasizes the importance of considering TTP as a potential complication of DKA.

A Rare Cause of Enteritis in an Adult Male

Introduction: IgA vasculitis is more commonly seen in the pediatric population than in adults. Rarely IgA vasculitis is associated with malignancy, most commonly solid tumor malignancies, although there are case reports of association with hematologic malignancies. We report a case of large B-cell lymphoma mimicking IgA vasculitis in a 33-year-old immunosuppressed male with a prior history of IgA vasculitis. Case Description/Methods: A 33-year-old Caucasian male post renal transplant from reflux nephropathy on chronic immunosuppression was hospitalized for postprandial epigastric abdominal pain, nausea, vomiting and diarrhea. Two years prior, he was admitted for the same symptoms, palpable purpura of the lower extremities and elevated serum IgA. Enteroscopy had shown duodenal and jejunal ulceration with biopsies staining positive for IgA, confirming IgA vasculitis. He had complete resolution with a steroid taper. His current presentation had resulted in multiple hospital admissions, but empiric trial of steroids failed to alleviate symptoms. Vitals were normal and exam was notable for epigastric tenderness. Labs were notable for WBC 19.00 x103/cmm with normal differential, hemoglobin 9.2 gm/dL (prior 11.0 gm/dL), CRP 20.7 mg/L, serum creatinine 2.7 mg/dL (prior 1.5 mg/dL), and urinalysis with proteinuria, sterile pyuria, and hematuria. CTA abdomen/pelvis revealed thickening of the duodenum with shotty mesenteric lymph nodes without ischemia. Enteroscopy revealed an erythematous duodenum and jejunum (figure A). Jejunal biopsy (figure B) revealed CD20 positive cells consistent with DLCBL (figure C). He was seen by oncology and treated with R-CHOP but later unfortunately expired due to COVID-19 complications. Discussion(s): Non small cell lung cancer and renal cell carcinoma are most commonly associated with IgA vasculitis. It may also be seen in both Hodgkin and Non-Hodgkin lymphomas in adult patients. If IgA vasculitis occurs after a malignancy is diagnosed, it may indicate that metastasis has occurred. Malignancy associated IgA vasculitis is more likely to have an incomplete response to steroids and requires treatment of the underlying malignancy to achieve remission. Our case illustrates posterior probability error and premature closure cognitive biases. We should consider alternative diagnoses rather than anchor on prior diagnoses even when presentations are similar. Our case also highlights the importance of considering occult malignancy in adults with diagnosis of IgA vasculitis.

Automated and Rapid ADAMTS13 Testing Using Chemiluminescence: Utility for Identification or Exclusion of TTP and Beyond.

Thrombotic thrombocytopenic purpura (TTP) is a prothrombotic condition caused by a significant deficiency of the enzyme, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). In the absence of adequate levels of ADAMTS13 (i.e., in TTP), plasma VWF accumulates, in particular as "ultra-large" VWF multimers, and this leads to pathological platelet aggregation and thrombosis. In addition to TTP, ADAMTS13 may be mildly to moderately reduced in a range of other conditions, including secondary thrombotic microangiopathies (TMA) such as those caused by infections (e.g., hemolytic uremic syndrome (HUS)), liver disease, disseminated intravascular coagulation (DIC), and sepsis, during acute/chronic inflammatory conditions, and sometimes also in COVID-19 (coronavirus disease 2019)). ADAMTS13 can be detected by a variety of techniques, including ELISA (enzyme-linked immunosorbent assay), FRET (fluorescence resonance energy transfer) and by chemiluminescence immunoassay (CLIA). The current report describes a protocol for assessment of ADAMTS13 by CLIA. This protocol reflects a rapid test able to be performed within 35 min on the AcuStar instrument (Werfen/Instrumentation Laboratory), although certain regional approvals may also permit this testing to be performed on a BioFlash instrument from the same manufacturer.

Drug-induced thrombotic thrombocytopenic purpura: A systematic review and review of European and North American pharmacovigilance data.

Many medications have been reported to be associated with thrombotic thrombocytopenic purpura (TTP) through pharmacovigilance data and published case reports. Whilst there are existing data available regarding drug-induced thrombotic microangiopathy, there is no available synthesis of evidence to assess drug-induced TTP (DI-TTP). Despite this lack of evidence, patients with TTP are often advised against using many medications due to the theoretical risk of DI-TTP. This systematic review evaluated the evidence for an association of medications reported as potential triggers for TTP. Of 5098 records available 261 articles were assessed further for eligibility. Fifty-seven reports, totalling 90 patients, were included in the final analysis. There were no cases where the level of association was rated as definite or probable, demonstrating a lack of evidence of any drug causing DI-TTP. This paucity of evidence was also demonstrated in the pharmacovigilance data, where 613 drugs were reported as potential causes of TTP without assessment of the strength of association. This systematic review demonstrates the need for standardised reporting of potential drugs causing TTP. Many reports omit basic information and, therefore, hinder the chance of finding a causative link if one exists.

Sarcoidosis-Associated Immune Thrombocytopenic Purpura and Focal Segmental Glomerulosclerosis

Purpose of study A 32-years old male with known multi-system sarcoidosis in remission for 5 years off treatment presented to the emergency room with complaints of generalized weakness, hematemesis, epistaxis, and bruises. Physical examination was notable for petechiae, ecchymosis along with papules and plaques suggestive of active sarcoid skin lesions on his extremities. Laboratory workup was significant for thrombocytopenia 3000/uL, acute kidney injury with sub-nephrotic proteinuria. Peripheral blood smear did not show evidence of hemolysis and direct Coombs test was negative. Infectious workup including COVID-19, HIV, and hepatitis serologies were negative. Computed Tomography (CT) of chest, abdomen, and pelvis showed mild splenomegaly and an increased number of sub-centimeter hilar and mediastinal lymph nodes. The patient was treated with dexamethasone 40 mg daily for 4 days and intravenousimmunoglobulins (IVIG-2 gm/kg) for possible Immune Thrombocytopenic Purpura (ITP) with improvement in platelet count to 42000/uL by day 3. His workup for AKI and sub-nephrotic proteinuria was negative apart from a positive ANA (1: 160) with low complements. The anti-phospholipid antibody panel was negative. The ACE level was markedly elevated (>80U/L). The patient could not get a renal biopsy due to severe thrombocytopenia. He was discharged but was re-admitted in 15 days for severe thrombocytopenia of 1000/uL, epistaxis, and bruising. We continued high dose steroids along with IVIG 1 gm/kg for refractory ITP with minimal response and started anti-CD20 agent (Rituximab) 375 mg/m2 weekly with thrombopoietin-receptor agonist (Eltrombopag). His platelets count improved in response to treatment and subsequent renal biopsy showed focal and segmental glomerulosclerosis along with mild interstitial fibrosis, tubular atrophy thought to be from long standing sarcoidosis. There was also evidence of focal arteriosclerosis with no evidence of granulomas, immune complex, complement, or IgG4 deposition. Given skin lesions, thrombocytopenia, extensive lymphadenopathy, and renal involvement with markedly elevated ACE levels the overall picture was consistent with active multi-system sarcoidosis. His platelet count increased to 177,000/uL at the time of discharge. Currently, the patient is on slow steroid taper along with Eltrombopag 25 mg every other day without any recurrence of his symptoms so far. Methods used We described one case of sarcoidosis with hematologic and renal involvement. Summary of results Our patient developed hematologic and renal complications approximately 6 years after being diagnosed with sarcoidosis. Initially, he did not demonstrate sufficient clinical response to IVIG and high dose steroids. However, after a course of anti-CD20 agent (Rituximab) and with the addition of thrombopoietin-receptor agonist (Eltrombopag) he showed improvement of platelet count and stabilization of the renal function. Currently, the patient is receiving maintenance therapy with Prednisone 7.5 mg daily along with Eltrombopag 25 mg twice weekly with no recurrence of ITP and stable renal function. A further decision on whether the patient needs another cycle of Rituximab will be determined by the patient's clinical course. Conclusions Highly variable manifestations of Sarcoidosis can pose a significant diagnostic and therapeutic challenge as can be seen from our case. ITP is a rare hematological manifestation of sarcoidosis and addition of anti-CD20 agents should be considered in refractory cases.

Immunoglobulin A (De Novo) Vasculitis after mRNA Moderna COVID-19 Vaccination: A Case Report

Concurrent with the administration of vaccines for the novel coronavirus (COVID-19), there have been many reported adverse effects, and many of them anticipated as with any vaccine administration. This case report, however, focuses on a patient who, shortly after receiving the first dose of the Moderna COVID-19 vaccine, developed a pruritic maculopapular rash with typical distribution and clinical characteristics, along with high levels of immunoglobulin A (IgA), consistent with IgA vasculitis, formerly known as Henoch-Schonlein purpura. Although there are reported cases of IgA vasculitis after different vaccine administrations, to our knowledge, there are no reports of development of this condition after COVID-19 vaccination. The patient did not have any other triggering events or factors that could be attributed to the development of this pathology. This case describes the development of IgA vasculitis after the COVID-19 vaccination. Copyright © Wolters Kluwer Health, Inc. All rights reserved.

Immune Thrombocytopenia Following Booster Dose of the Moderna mRNA-1273 Vaccine.

Vaccine-mediated immune thrombocytopenia, although previously reported, is considered exceedingly rare. The probability of the incidence of profound thrombocytopenia following the COVID-19 mRNA-based vaccine has been less elucidated. We present the case of an 81-year-old female patient who became profoundly thrombocytopenic with bleeding manifestations six days after the Moderna mRNA-1273 vaccine administration. Fortunately, she exhibited platelet count recovery after treatment with intravenous immunoglobulins and steroid therapy. Furthermore, we show that the inherent risk of COVID-19 infection leading to thrombocytopenia significantly outweighs the vaccine's risk.

Cutaneous manifestations of COVID-19.

COVID - 19 can be accompanied by a variety of cutaneous abnormalities, which mainly include vascular lesions chilblain - like lesions, livedo reticularis, purpura, ecchymosis, acral cyanosis, gangrene, etcand inflammatory lesionsdiffuse erythema, morbilliform exanthem, acute urticaria, varicella- like exanthem, etc. Some types of skin lesions may be the first symptom or the only clinical manifestation of COVID-19.Copyright © 2022 Chinese Journal of Dermatology. All rights reserved.

Henoch Schonlein purpura secondary to vaccination against COVID-19, review of the responsible mechanisms and report of 1 case

Case report Introduction: The COVID-19 pandemic has generated an inexorable cost to governments and a high mortality in general terms, the vaccination process is the only effective strategy to reduce morbidity and mortality in general, however, such administration is not without risks. Case presentation: Female patient of the seventh decade who is vaccinated against COVID-19 and 4 days after the second dose of vaccine against COVID-19 begins to present purpuric lesions that begin in the lower limbs and progressively ascend to the trunk associated with intense arthralgias, abdominal pain and nausea, presents macroscopic rectal bleeding, is admitted finding platelet counts lower than 10 thousand platelets, the diagnosis of a Henoch Scholein purpura associated with a vaccine against COVID-19 was confirmed no requiring specific immunosuppressive therapy with resolution at 21 days. The triggering mechanisms are being studied and described as similar to immunological thrombocytopenia due to heparins. Antibodies against platelet factor 4 have been reported so far. The test known as PIFPA (PF4-induced flow cytometry-based platelet activation) is a cytometric test with high sensitivity and specificity, only available in specialized laboratories, being described for the moment as the only test that allows the detection of immunological thrombocytopenic phenomena secondary to vaccination against COVID-19. Discussion(s): The present case constitutes the appearance of a Henoch Scholein Purpura, a rare pathology with a wide repertoire of triggering events, with infections and vaccine reactions among the main triggers. The present vaccine reaction is rare, being the specific anecdotal, until now there are very few descriptions in the literature about this type of vaccine reaction, which is why it is decided to publish it, mentioning the most recent scientific evidence available on this area. It is noteworthy that these are rare reactions that should not make us underestimate continuing with vaccination campaigns as the best strategy to prevent the advance of this pandemic.

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.

Graves' disease-induced immune thrombocytopenic purpura in an African female: a case report.

BACKGROUND: Immune thrombocytopenic purpura is a condition associated with an unusual, unexplained, and sometimes very severe reduction in the level of platelets in the blood. Though documented, its association with Graves' disease is not very common and can easily be missed or misdiagnosed, leading to excessive bleeding and mortality. Treatment with steroids and antithyroid medications has been shown to be beneficial in correcting thrombocytopenia in these patients, although the response is varied. We report on a patient with Graves' disease who presents with immune thrombocytopenic purpura. CASE PRESENTATION: A 37-year-old Ghanaian female presented to our hospital's emergency department with a complaint of palpitations, difficulty breathing, easy fatigue, and headaches. She had been referred from a peripheral hospital as a case of thrombocytopenia, severe anemia, and anterior neck swelling. She was diagnosed with Graves' disease 2 years ago, became euthyroid during treatment, but defaulted. On further examination and investigation, she was diagnosed with immune thrombocytopenic purpura and was also found to have elevated free T3 and T4, and suppressed thyroid stimulating hormone. She also had high thyroid autoantibodies. She was initially started on oral prednisolone but there was no stabilization of platelets until methimazole was introduced, which improved and normalized her platelet count. CONCLUSION: The association of Graves' disease with immune thrombocytopenic purpura, though documented, is uncommon, and very few cases have been reported thus far. There have not been any reported cases in Ghana or Sub-Saharan Africa and hence, clinicians should be aware of this association when investigating immune thrombocytopenic purpura and should consider Graves' disease as a possible cause. From this study, we observed that there was no improvement in platelet count following the use of corticosteroid therapy until methimazole was started.

Renal Thrombotic Microangiopathy: A Review.

Thrombotic microangiopathy (TMA), a pathological lesion observed in a wide spectrum of diseases, is triggered by endothelial injury and/or dysfunction. Although TMA lesions are often accompanied by clinical features of microangiopathic hemolytic anemia, thrombocytopenia, and ischemic end-organ injury, renal-limited forms of TMA are not infrequently encountered in clinical practice. The presence of renal-limited manifestations can be diagnostically challenging, often delaying the initiation of targeted therapy. Prompt investigation and empirical treatment of TMA is warranted to reduce associated morbidity and mortality. Major advances have been made with respect to the pathophysiology of primary TMA entities, with the subsequent development of novel diagnostic tools and lifesaving therapies for diseases like thrombotic thrombocytopenic purpura and complement-mediated TMA. This article will review the clinical presentation and pathologic hallmarks of TMA involving the kidney, and the disease-specific mechanisms that contribute to the endothelial injury that characterizes TMA lesions. Diagnostic approach and both empirical and disease-specific treatment strategies will be discussed, along with the potential role for emerging targeted disease-specific therapies.

Changes in the Incidence of Immune Thrombocytopenia in the Coronavirus Disease 2019 Era: A Nationwide Observational Study in Korea.

Purpose: We investigated whether nonpharmaceutical interventions (NPI) to reduce the spread of coronavirus disease 2019 (COVID-19) was associated with a change in the incidence of immune thrombocytopenia (ITP). Patients and Methods: Using the Korean Health Insurance Review and Assessment Services (HIRA) database, individuals newly diagnosed with ITP between January 2015 and December 2020 were identified. The NPI period was defined as February 2020 to December 2020. The ITP incidence in the NPI period was compared with the mean annual incidence during the same months in the pre-NPI period and the incidence predicted by the autoregressive integrated moving average model. Results: In total, 25,723 patients were identified, and the overall annual incidence of ITP was 8.28 per 100,000 persons ([95% confidence interval (CI): 8.18-8.39]. The ITP incidence in the NPI period was 6.60 per 100,000 person-years (95% CI: 6.37-6.85), 0.77 times (95% CI: 0.74-0.80) lower than that during the pre-NPI period [8.62/100,000 (95% CI: 8.50-8.74)]. With the exception for patients aged ≥70 years, the ITP incidence was significantly lower in the NPI period than in the pre-NPI period. The most significant decline in the ITP incidence during the NPI period was observed in the 0-9 years age group [25.76/100,000 vs 14.01/100,000, P <0.001; incidence rate ratio (IRR): 0.54 (95% CI: 0.51-0.58)]. The intravenous immunoglobulin-treated ITP incidence in the NPI period was 1.69/100,000 (95% CI: 1.58-1.81), 0.79 times (95% CI: 0.73-0.85) lower than that in the pre-NPI period 2.15/100,000 (95% CI: 2.09-2.21)]. The incidence of steroid-treated ITP was lower in the NPI period than in the pre-NPI period (2.73/100,000 vs 2.2/100,000, P <0.001), with an IRR of 0.80 (95% CI: 0.76-0.83). Conclusion: This nationwide study revealed a significant decrease in ITP incidence, particularly among children, after the implementation of NPI.