A 10-year-old girl was admitted with a 38-hour history of widespread subcutaneous petechiae and hematuria and a 6-hour history of jaundice and oliguria. Physical examination revealed widespread subcutaneous petechiae and jaundice of the skin and sclera. Laboratory tests showed anemia, thrombocytopenia, acute kidney injury, and markedly elevated lactate dehydrogenase. Thrombotic microangiopathy was initially diagnosed, with a high suspicion of atypical hemolytic uremic syndrome (aHUS). Eculizumab was initiated within 9 hours of admission (within 48 hours of onset). After the first infusion, hemolysis rapidly ceased, and the platelet count and renal function gradually returned to normal. Whole-exome sequencing identified homozygous deletions of CFHR1 exon 2 and CFHR4 exon 1. aHUS typically has abrupt onset and rapid progression. Clinicians should maintain high suspicion for aHUS when the triad of thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury is present. Ultra-early eculizumab (within 48 hours of onset) rapidly blocks complement-mediated thrombotic microangiopathy, reverses organ injury, and improves long-term prognosis. Additionally, complement-related genetic testing is important for etiological clarification and individualized determination of eculizumab treatment duration.
Humans ; Antibodies, Monoclonal, Humanized/administration & dosage* ; Female ; Atypical Hemolytic Uremic Syndrome/drug therapy* ; Child ; Complement C3b Inactivator Proteins

Critical care emphasizes critical thinking, focuses on the triggers that lead to disease progression, and attaches great importance to early diagnosis of diseases and assessment of the compensatory capacity of vital organs. Pregnancy-associated atypical hemolytic uremic syndrome (P-aHUS) is relatively rare in the intensive care unit (ICU). Most cases occur within 10 weeks after delivery. Severe cases can be life-threatening. It characterized by microangiopathic hemolytic anemia, decreased platelet count (PLT), and acute kidney injury (AKI). Early clinical diagnosis is difficult due to its similarity to various disease manifestations. On January 28, 2024, a 26-year-old pregnant woman at 26⁺³ weeks gestation was transferred to the ICU 19 hours post-vaginal delivery due to abdominal pain, reduced urine output, decreased PLT, elevated D-dimer, tachycardia, increased respiratory rate and declined oxygenation. On the day of ICU admission, the critical care physician identified the causes that triggered the acute respiratory and circulatory events based on the "holistic and local" critical care thinking. The condition was stabilized rapidly by improving the capacity overload. In terms of etiological diagnosis, under the guidance of the "point and face" critical care thinking, starting from abnormality indicators including a decrease in hemoglobin (Hb) and PLT and elevated D-dimer and fibrin degradation product (FDP) without other abnormal coagulation indicators, the critical care physician ultimately determined the diagnosis direction of thrombotic microangiopathy (TMA) by delving deeply into the essence of the disease and formulating a laboratory examination plan in a reasonable and orderly manner. In terms of in-depth diagnosis, combining the disease development process, family history, and past history, applying the two-way falsification thinking of "forward and reverse" as well as "questioning and hypothesis", the diagnosis possibilities of preeclampsia, HELLP syndrome [including hemolysis (H), elevated liver function (EL) and low platelet count (LP)], thrombotic thrombocytopenic purpura (TTP), typical hemolytic uremic syndrome (HUS), and autoimmune inflammatory diseases inducing the condition was ruled out. The diagnosis of complement activation-induced P-aHUS was finally established for the patient, according to the positive result of the complement factor H (CFH). Active decision was made in the initial treatment. The plasma exchange was initiated early. "Small goals" were formulated in stages. The "small endpoints" were dynamically controlled in a goal-oriented manner to achieve continuous realization of the overall treatment effect through phased "small goals". On the 5th day of ICU treatment, the trend of microthrombosis in the patient was controlled, organ function damage was improved, and the patient was transferred out of the ICU. It is possible to reach a favorable clinical outcome for critically ill patients by applying a critical care mindset to quickly integrate diagnostic and therapeutic strategies, accurately identifying the triggers and causes that led to the progression of the disease, and using critical care medical techniques for early and effective intervention.
Humans ; Female ; Pregnancy ; Adult ; Atypical Hemolytic Uremic Syndrome/therapy* ; Intensive Care Units ; Pregnancy Complications, Hematologic/therapy* ; Critical Care

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and multi-organ damage, with the kidneys being predominantly affected. aHUS results from dysregulation of the complement alternative pathway, triggered by factors including infection, pregnancy, and surgery, among others. Therefore, complement inhibitors play a crucial role in the treatment of aHUS by blocking abnormal activation of the complement system and improving patients' prognosis. This consensus, developed by the Multidisciplinary Consensus Working Group on Atypical Hemolytic Uremic Syndrome Diagnosis and Treatment, is based on the latest literature and guidelines, discusses the pathogenesis, diagnosis and differential diagnosis, and treatment strategies for aHUS, and provides a guide and reference for the standardized diagnosis and management of aHUS in China.
Humans ; Atypical Hemolytic Uremic Syndrome/therapy* ; Consensus ; Diagnosis, Differential ; Prognosis

OBJECTIVE: To explore the clinical characteristics and genetic etiology for a child with atypical Hemolytic uremic syndrome (aHUS) in conjunct with nephrotic level proteinuria. METHODS: A child patient who had visited the Affiliated Hospital of Qingdao University on June 25, 2020 was selected as the study subject. Clinical data of the patient was collected. Whole exome sequencing (WES) was carried out for the child, and candidate variant was verified by Sanger sequencing of the child and his parents. RESULTS: The child, an 8-month-old male, had presented mainly with edema, oliguria, hematuria, nephrotic level proteinuria, anemia, thrombocytopenia, increased creatinine and urea, hypercholesterolemia but normal complement levels. Genetic testing revealed that he has harbored compound heterozygous variants of the DGKE gene, namely c.12_18dupGAGGCGG (p.P7fs*37) and c.1042G>T (p.D348Y), which were respectively inherited from his father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variants were classified as likely pathogenic and variant of uncertain significance, respectively. By combining his clinical manifestations and results of genetic testing, the child was diagnosed with aHUS with nephrotic level proteinuria. CONCLUSION For infants and young children with aHUS in conjunct with nephrotic level proteinuria, variants of the DGKE gene should be screened. Above finding has expanded the mutational spectrum of the DGKE gene.
Infant ; Female ; Humans ; Child ; Male ; Child, Preschool ; Atypical Hemolytic Uremic Syndrome/diagnosis* ; Mutation ; Genetic Testing ; Thrombocytopenia/genetics* ; Proteinuria/genetics*

Antibodies, Monoclonal, Humanized/therapeutic use* ; Atypical Hemolytic Uremic Syndrome/drug therapy* ; Humans

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) involves dysregulation of the complement system, but whether this also occurs in thrombotic thrombocytopenic purpura (TTP) remains unclear. Although these conditions are difficult to differentiate clinically, TTP can be distinguished by low (<10%) ADAMTS13 activity. The aim was to identify the differences in complement activation products between TTP and aHUS and investigate ADAMTS13 activity as a prognostic factor in aHUS. METHODS: We analyzed patients with thrombotic microangiopathy diagnosed as TTP (N=48) or aHUS (N=50), selected from a Korean registry (N=551). Complement activation products in the plasma samples collected from the patients prior to treatment and in 40 healthy controls were measured by ELISA. RESULTS: The levels of generalized (C3a), alternate (factor Bb), and terminal (C5a and C5b-9) markers were significantly higher (all P<0.01) in the patients than in the healthy controls. Only the factor Bb levels significantly differed (P=0.008) between the two disease groups. In aHUS patients, high normal ADAMTS13 activity (≥77%) was associated with improved treatment response (OR, 6.769; 95% CI, 1.605–28.542; P=0.005), remission (OR, 6.000; 95% CI, 1.693–21.262; P=0.004), exacerbation (OR, 0.242; 95% CI, 0.064–0.916; P=0.031), and disease-associated mortality rates (OR, 0.155; 95% CI, 0.029–0.813; P=0.017). CONCLUSION: These data suggest that complement biomarkers, except factor Bb, are similarly activated in TTP and aHUS patients, and ADAMTS13 activity can predict the treatment response and outcome in aHUS patients.
Atypical Hemolytic Uremic Syndrome ; Biomarkers ; Complement Activation ; Complement System Proteins ; Enzyme-Linked Immunosorbent Assay ; Humans ; Mortality ; Plasma ; Purpura, Thrombotic Thrombocytopenic ; Thrombotic Microangiopathies

Atypical hemolytic uremic syndrome (aHUS), a rare form of thrombotic microangiopathy, is distinguished from the typical form by the absence of a preceding verotoxin-producing Escherichia coli infection. Notably, aHUS occurs in association with genetic or acquired disorders causing dysregulation of the alternative complement pathway. Patients with aHUS may show the presence of anti-complement factor H (CFH) autoantibodies. This acquired form of aHUS (anti-CFH-aHUS) primarily affects children aged 9–13 years. We report a case of a 13-year-old Lao girl with clinical features of aHUS (most likely anti-CFH-aHUS). The initial presentation of the patient met the classical clinical triad of thrombotic microangiopathy (microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury) without preceding diarrheal illness. Low serum levels of complement 3 and normal levels of complement 4 indicated abnormal activation of the alternative complement pathway. Plasma infusion and high-dose corticosteroid therapy resulted in improvement of the renal function and hematological profile, although the patient subsequently died of infectious complications. This is the first case report that describes aHUS (possibly anti-CFH-aHUS) in Laos.
Adolescent ; Anemia, Hemolytic ; Atypical Hemolytic Uremic Syndrome ; Autoantibodies ; Child ; Complement C3 ; Complement C4 ; Complement Factor H ; Complement Pathway, Alternative ; Female ; Humans ; Immunosuppression ; Kidney ; Laos ; Plasma ; Shiga-Toxigenic Escherichia coli ; Thrombocytopenia ; Thrombotic Microangiopathies

BACKGROUND: Thrombotic microangiopathy (TMA) with non-deficient ADAMTS-13 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif 13) outcome is unknown hence the survival analysis correlating with ADAMTS-13 activity is conducted in Malaysia. METHODS: This was a retrospective epidemiological study involving all cases of TMA from 2012–2016. RESULTS: We evaluated 243 patients with a median age of 34.2 years; 57.6% were female. Majority of the patients were Malay (62.5%), followed by Chinese (23.5%) and Indian (8.6%). The proportion of patients with thrombotic thrombocytopenic purpura (TTP) was 20.9%, 72.2% of which were acquired while 27.8% were congenital. Patients with ADAMTS-13 activity ≥5% had a four-fold higher odds of mortality compared to those with ADAMTS-13 activity <5% (odds ratio: 4.133, P=0.0425). The mortality rate was 22.6% (N=55). Most cases had secondary etiologies (42.5%), followed by acquired TTP (16.6%), atypical hemolytic uremic syndrome (HUS) or HUS (12.8%) and congenital TTP (6.4%). Patients with secondary TMA had inferior overall survival (P=0.0387). The secondary causes comprised systemic lupus erythematosus (30%), infection (29%), pregnancy (10%), transplant (8%), malignancy (6%), and drugs (3%). Transplant-associated TMA had the worst OS (P=0.0016) among the secondary causes. Plasma exchange, methylprednisolone and intravenous immunoglobulin were recorded as first-line treatments in 162 patients, while rituximab, bortezomib, vincristine, azathioprine, cyclophosphamide, cyclosporine, and tacrolimus were described in 78 patients as second-line treatment. CONCLUSION: This study showed that TMA without ADAMTS-13 deficiency yielded inferior outcomes compared to TMA with severeADAMTS-13 deficiency, although this difference was not statistically significant.
Asian Continental Ancestry Group ; Atypical Hemolytic Uremic Syndrome ; Azathioprine ; Bortezomib ; Cyclophosphamide ; Cyclosporine ; Epidemiologic Studies ; Female ; Humans ; Immunoglobulins ; Lupus Erythematosus, Systemic ; Malaysia* ; Methylprednisolone ; Mortality ; Plasma Exchange ; Pregnancy ; Purpura, Thrombotic Thrombocytopenic ; Retrospective Studies ; Rituximab ; Tacrolimus ; Thrombospondins ; Thrombotic Microangiopathies* ; Vincristine

Hemolytic uremic syndrome (HUS) is often encountered in children with acute kidney injury. Besides the well-known shiga toxin-producing Escherichia coli-associated HUS, atypical HUS (aHUS) caused by genetic complement dysregulation has been studied recently. aHUS is a rare, chronic, and devastating disorder that progressively damages systemic organs, resulting in stroke, end-stage renal disease, and death. The traditional treatment for aHUS is mainly plasmapheresis or plasma infusion; however, many children with aHUS will progress to chronic kidney disease despite plasma therapy. Eculizumab is a newly developed biologic that blocks the terminal complement pathway and has been successfully used in the treatment of aHUS. Currently, several guidelines for aHUS, including the Korean guideline, recommend eculizumab as the first-line therapy in children with aHUS. Moreover, life-long eculizumab therapy is generally recommended. Further studies on discontinuation of eculizumab are needed.
Acute Kidney Injury ; Atypical Hemolytic Uremic Syndrome ; Child ; Complement System Proteins ; Escherichia ; Hemolytic-Uremic Syndrome ; Humans ; Kidney Failure, Chronic ; Plasma ; Plasmapheresis ; Renal Insufficiency, Chronic ; Stroke

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare disease that is often associated with genetic defects. Mutations of complement factor H (CFH) are the most common genetic defects that cause aHUS and often result in end-stage renal disease. Since CFH is mainly produced in the liver, liver transplantation (LT) has been performed in patients with defective CFH. METHODS: The clinical courses of four kidney allograft recipients who lost their native kidney functions due to aHUS associated with a CFH mutation were reviewed. RESULTS: Subject A underwent kidney transplantation (KT) twice, aHUS recurred and the allograft kidney failed within a few years. Subject B received a KT and soon experienced a recurrence of aHUS coinciding with infection. Her allograft kidney function has worsened, and she remains on plasma infusion therapy. Subject C underwent LT followed by KT. She is doing well without plasma infusion therapy after combined LT-KT for 3 years. Subject D received KT following LT and is now recurrence-free from aHUS. CONCLUSION: In patients with aHUS associated with a CFH mutation, KT without LT was complicated with a recurrence of aHUS, which might lead to allograft loss. Conversely, LT was successful in preventing the recurrence of aHUS and thus might be another option for a recurrence-free life for aHUS patients associated with CFH mutation.
Allografts ; Atypical Hemolytic Uremic Syndrome ; Complement Factor H ; Complement System Proteins ; Humans ; Kidney Failure, Chronic ; Kidney Transplantation ; Kidney ; Liver Transplantation ; Liver ; Plasma ; Rare Diseases ; Recurrence