Secondary thrombotic microangiopathy or secondary HUS: drugs or malignant hypertension to blame? Case report and review of the literature; [Вторичная тромботическая микроангиопатия или вторичный ГУС: виноваты наркотики или злокачественная артериальная гипертония? Клиническое наблюдение и обзор литературы]

Currently, thrombotic microangiopathy (TMA) is a common finding in the histological examination of kidney biopsy specimens, while verification of the nosological diagnosis is difficult due to the many etiological factors and the variety of clinical phenotypes. Today, along with primary TMAs, which include thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), a large group of secondary TMAs associated with a variety of diseases and conditions, considered secondary HUS, is attracting more and more attention. The article presents a clinical case of the development of thrombotic microangiopathy in a 48-year-old man with a history of intravenous drug user who suffered from severe arterial hypertension for a long time. A feature of the disease was clinically – the almost complete absence of hematological manifestations with a progressive nature of nephropathy with an outcome in end-stage kidney disease, morphologically – mainly chronic changes in small extraglomerular vessels (arteries and arterioles), which led to severe ischemic damage to the glomeruli. Considering the predominantly chronic nature of the morphological manifestations of TMA, the absence of signs of acute TMA, and hematological syndrome, the patient did not undergo plasma therapy. In connection with the development of end-stage kidney disease, hemodialysis was initiated. The presented observation illustrates the complex genesis of secondary TMA in a patient with a history of drug addiction and severe arterial hypertension approaching malignant downstream. The presence in the anamnesis of such complement-activating conditions as intravenous drug use, severe arterial hypertension, as well as vaccination against a new coronavirus infection preceding the clinical manifestation, allowed us to interpret this condition as secondary HUS, which, however, does not exclude the presence of protein gene mutations, regulators of the alternative pathway of complement activation, which could act as a predisposing factor, which requires a genetic study of the complement system, since the information obtained will determine the tactics of management in case of kidney transplantation. In addition, this clinical observation demonstrates the importance of a thorough history taking in such patients, the analysis of which will help to identify complement-activating conditions and thereby accelerate the verification of the diagnosis. © 2022 Authors. All rights reserved.