Postoperative atypical hemolytic uremic syndrome associated with complement c3 mutation

Life-Threatening Diffuse Alveolar Hemorrhage and Graft Failure in Atypical Hemolytic Uremic Syndrome with C3 Gene Mutation following Kidney Transplant

INTRODUCTION

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) disease entity primarily attributed to genetic or acquired abnormalities in the alternative complement pathway. TMA can manifest in kidney transplant (KT) recipients owing to various factors, resulting in diverse clinical presentations. Given its adverse effects on allograft function and patient prognosis, genetic diagnostic approaches for aHUS are essential. Although rarely associated with diffuse alveolar hemorrhage, only a few mild cases have been reported to date. In this report, we present a case of the patient who experienced recurrent and life-threatening diffuse alveolar hemorrhage shortly after KT accompanied by graft failure.

CASE PRESENTATION

An 18-year-old girl who underwent deceased donor KT developed recurrent diffuse alveolar hemorrhage with acute kidney injury, leading to graft failure. Microangiopathic hemolytic anemia, thrombocytopenia, and schistocytes in blood smears suggested the presence of TMA. The patient underwent therapeutic plasma exchange, and clinical condition improved during the procedure. Genetic testing confirmed a heterozygous c.1273C>T mutation in C3 gene, leading to the diagnosis of aHUS. However, after discontinuing the plasma exchange, the patient experienced seizures, recurrent pulmonary hemorrhage, and oliguria with recurring TMA features. The patient subsequently underwent eculizumab treatment, which resulted in complete remission, although hemodialysis was continued after graft nephrectomy.

CONCLUSION

In patients presenting with unexplained pulmonary hemorrhage and kidney injury following KT, genetic aHUS should be considered as a potential differential diagnosis for TMA.

Severe Acute Kidney Injury in Cardiovascular Surgery: Thrombotic Microangiopathy as a Differential Diagnosis to Ischemia Reperfusion Injury. A Retrospective Study

BACKGROUND

Acute kidney injury (AKI) after cardiovascular surgery (CVS) infers high morbidity and mortality and may be caused by thrombotic microangiopathy (TMA). This study aimed to assess incidence, risk factors, kidney function, and mortality of patients with a postoperative TMA as possible cause of severe AKI following cardiovascular surgery.

METHODS

We analyzed retrospectively all patients admitted to the ICU after a cardiovascular procedure between 01/2018 and 03/2019 with severe AKI and need for renal replacement therapy (RRT). TMA was defined as post-surgery-AKI including need for RRT, hemolytic anemia, and thrombocytopenia. TMA patients were compared to patients with AKI requiring RRT without TMA.

RESULTS

Out of 893 patients, 69 (7.7%) needed RRT within one week after surgery due to severe AKI. Among those, 15 (21.7%) fulfilled TMA criteria. Aortic surgery suggested an increased risk for TMA (9/15 (60.0%) vs. 7/54 (31.5%), OR 3.26, CI 1.0013-10.64). Ten TMA patients required plasmapheresis and/or eculizumab, and five recovered spontaneously. Preoperative kidney function was significantly better in TMA patients than in controls (eGFR 92 vs. 60.5 mL/min, p = 0.004). However, postoperative TMA resulted in a more pronounced GFR loss (ΔeGFR -54 vs. -17 mL/min, p = 0.062). There were no deaths in the TMA group.

CONCLUSION

Our findings suggest TMA as an important differential diagnosis of severe AKI following cardiovascular surgery, which may be triggered by aortic surgery. Therefore, early diagnosis and timely treatment of TMA could reduce kidney damage and improve mortality of AKI following cardiovascular surgery, which should be further investigated.

Atypical Hemolytic Uremic Syndrome following Acute Type A Aortic Dissection

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA)-related disease that manifests as a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI) and is caused by uncontrolled activation of the complement system. We report the case of a 61-year-old woman with acute type A aortic dissection that subsequently developed into aHUS. The hematologic disorders underlying aHUS improved after treatment with the complement inhibitor eculizumab. It is important to consider aHUS when a patient clinically develops a triad of microangiopathic hemolytic anemia, thrombocytopenia, and an increasing creatinine level following cardiovascular surgery.

Postoperative Atypical Hemolytic Uremic Syndrome Treated Successfully with Eculizumab

Atypical hemolytic uremic syndrome (aHUS) is a rare type of HUS associated with dysregulation of the alternative complement pathway. We herein report the findings of a 43-year-old woman who developed aHUS two days after myomectomy. The serum C3 level was low and the sheep erythrocyte hemolytic assay showed a moderate hemolysis. The renal insufficiency progressed despite performing plasma exchange therapy, although a partial hematological response was observed. Thus, the patient was subsequently treated with the anti-C5 antibody eculizumab, which promptly improved and normalized the renal function. Although aHUS after surgery has rarely been reported, it needs to be promptly recognized and treated with eculizumab to prevent irreversible renal damage.