The document provides a comprehensive overview of the diagnosis, monitoring, and treatment of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) with renal involvement, focusing on granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). It outlines the definitions, clinical presentation, histopathological classification, monitoring strategies, induction and maintenance treatments, as well as special considerations for relapsing, refractory, and frail patients with renal AAV. The document was prepared by the Catalan Group for the Study of Glomerular Diseases (GLOMCAT), which comprises nephrologists with extensive experience in the diagnosis and treatment of AAV patients. Several virtual and face-to-face meetings were held for coordination, section assignments, and content discussion. An exhaustive and systematic search of the literature was carried out, which included, among others, the following databases: PubMed, EMBASE, Cochrane Library, Google Scholar, and ClinicalTrials.gov, as well as the abstract books of national and international congresses. Overall, the document provides a comprehensive guide for clinicians managing patients with renal AAV, offering evidence-based recommendations for diagnosis, monitoring, and treatment across various clinical scenarios.

Acute myeloid leukemia (AML) has not been identified as a cause of secondary hemolytic–uremic syndrome (HUS). This case report describes a woman who developed severe HUS at the time of AML diagnosis and responded favorably to initial treatment with eculizumab, which stabilized her condition and allowed for treatment of the AML. After one year, with stable renal function and genetic studies reported as normal, eculizumab was successfully discontinued. The prompt use of eculizumab was critical to the patient’s survival and improvement in renal function, highlighting the efficacy of early eculizumab treatment in secondary HUS.