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Haemolytic uraemic syndrome (HUS) is a clinical entity defined as the triad of nonimmune haemolytic anaemia, thrombocytopenia, and acute renal failure, in which the underlying lesions are mediated by systemic thrombotic microangiopathy (TMA). Different causes can induce the TMA process that characterizes HUS. In this document we consider atypical HUS (aHUS) a sub-type of HUS in which the TMA phenomena are the consequence of the endotelial damage in the microvasculature of the kidneys and other organs due to a disregulation of the activity of the complement system. In recent years, a variety of aHUs-related mutations have been identified in genes of the the complement system, which can explain approximately 60% of the aHUS cases, and a number of mutations and polymorphisms have been functionally characterized. These findings have stablished that aHUS is a consequence of the insufficient regulation of the activiation of the complement on cell surfaces, leading to endotelial damage mediated by C5 and the complement terminal pathway. Eculizumab is a monoclonal antibody that inhibits the activation of C5 and blocks the generation of the pro-inflammatory molecule C5a and the formation of the cell membrane attack complex. In prospective studies in patients with aHUS, the use of Eculizumab has shown a fast and sustained interruption of the TMA process and it has been associated with significative long-term improvements in renal function, the interruption of plasma therapy and important reductions in the need of dialysis. According to the existing literature and the accumulated clinical experience, the Spanish aHUS Group published a consensus document with recommendations for the treatment of aHUs (Nefrologia 2013;33[1]:27-45). In the current online version of this document, we update the aetiological classification of TMAs, the pathophysiology of aHUS, its differential diagnosis and its therapeutic management., (Copyright © 2015 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Haemolytic uraemic syndrome (HUS) is a clinical entity defined as the triad of nonimmune haemolytic anaemia, thrombocytopenia, and acute renal failure, in which the underlying lesions are mediated by systemic thrombotic microangiopathy (TMA). Atypical HUS (aHUS) is a sub-type of HUS in which the TMA phenomena are the consequence of decreased regulation of the alternative complement pathway on cell surfaces due to a genetic cause. aHUS is an extremely rare disease that, despite the administration of standard treatment with plasma therapy, often progresses to terminal chronic renal failure with a high associated rate of mortality. In recent years, research has established the key role that the complement system plays in the induction of endothelial damage in patients with aHUS, through the characterisation of multiple mutations and polymorphisms in the genes that code for certain complement factors. Eculizumab is a monoclonal antibody that inhibits the terminal fraction of the complement protein, blocking the formation of a cell membrane attack complex. In prospective studies in patients with aHUS, administering eculizumab produces a rapid and sustained interruption in the TMA process, with significant improvements in long-term renal function and an important decrease in the need for dialysis or plasma therapy. In this document, we review and bring up to date the important aspects of this disease, with special emphasis on how recent advancements in diagnostic and therapeutic processes can modify the treatment of patients with aHUS.

Fifty five patients with Schöelein-Henoch nephropathy were reviewed. These patients were divided into five groups according to the clinical picture initially presented: 1. Hematuria with proteinuria. 2. Hematuria with nephrotic syndrome. 3. Isolated hematuria. 4. Hematuria, nephrotic syndrome and renal failure. 5. Proteinuria. From a histopathological point of view, they were classified into six groups according to ISKDC criteria. A strong correlation was found between clinical presentation and histological lesion. The worst prognosis corresponded to patients with nephrotic syndrome and renal failure, whose biopsy revealed more than 75% of glomeruli with epithelial crescents.

Clinical and radiological studies of seven patients with autosomic recessive malignant osteopetrosis are presented. Diagnosis was established before the age of 3 months in six cases and at 7 months in one. In all cases the presenting signs were pallor and hepatosplenomegaly with associated neurological involvement in five. All patients had normocytic normochromic anemia, leucopenia and thrombocytopenia with features of extramedullary hematopoiesis. Radiological studies revealed increase in the density of bones with "mask" appearance of facial bones and diminished size of optic foramina. Long bones showed absence of normal trabeculae and anomalies in modeling with methaphiseal bands and "bone within bone" images. There was hypocalcemia and hypophosphatemia with slight increases in alkaline phosphatase; parathormone was normal. Clinical course was characterized by progressive pancytopenia, recurrent infections and neurological deterioration with convulsions, nistagmus and optic atrophy. Five out of the seven patients died after a median of 3 months, due to infections or haemorrhage. The patient diagnosed at 7 months of age presented bilateral optic atrophy and moderate anemia; no other complications appeared after 2 year follow-up. Histological findings included substitution of bone marrow by chondro-osseous tissue; focal obsteoblastic and osteoclastic activity in calcified cartilage, and myeloid metaplasia in liver, spleen, lymph nodes and kidneys. The lesions are in agreement with the concept of a defect in bone formation-resorbtion balance; dysfunction of both osteoclasts and osteocytes is implicated in the pathogenesis. Unlike experimental disease, osteopetrosis in man is probably an heterogeneous disease and appropriate therapy should be individualized. Nevertheless, at present, the only favorable results have been obtained with bone-marrow transplantation.

Authors describe initial characteristics, clinical course and response to treatment of 13 children, aged from eight months to nine years, with acquired aplastic anaemia. Six of the children had been exposed to products with potential bone-marrow toxicity: chloranphenicol (1), pirazolones (3) and insecticides (2). Pancytopenia was severe in twelve and moderate in one. Five patients with severe aplastic anaemia were given antilymphocytic (2) or antithymocytic (3) (ATG) gammaglobulins; two of those treated with ATG responded after two and five months respectively and there was no response in the other three. Twelve patients were given androgen treatment (oxymetholone or nandrolone decanoate): four, two of whom previously had received ATG, followed a favorable course. None of the severe initial pancytopenic patients responded to androgen single agent treatment. No marrow transplant was performed in any of the children. Eight of the thirteen patients died one to 37 months after onset (median, 6 months) and five (38%) are alive after 21 months to 10 years, corresponding to two patients with moderate and three with severe initial pancytopenia. Importance of an appropriate supportive treatment during initial stages of the disease and the probable efficacy or immunosupressive treatment in certain patients must be underlined.