Clinico-histological features of thrombotic microangiopathy in renal biopsies: a retrospective study

Abstract

Objective: Thrombotic microangiopathy (TMA) is often first detected on a renal biopsy performed for renal manifestations. Apart from hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura, there are various secondary conditions associated with TMA. This study analyzes the clinico-pathological spectrum, etiological factors and renal outcome of TMA diagnosed on renal biopsy. Material and Method:A retrospective evaluation of renal biopsies for TMA over 5.5 years was performed. Clinical and laboratory data was collected from patient records.Results: A total of 40 biopsies from 39 patients showed TMA comprising 33 native and 7 transplant biopsies. Malignant hypertension (n=13) was the most common etiology in native biopsies followed by postpartum TMA (n=7), atypical HUS (aHUS) (n=7), and lupus nephritis (n=6). TMA in transplant biopsies was due to acute rejection (n=4) and CNI toxicity (n=3). Serum creatinine was high in most patients (mean 5.6 + 2.5 mg/ dl). aHUS showed the highest mean LDH levels and the lowest average platelet counts. Renal biopsies in malignant hypertension and postpartum TMA showed isolated arterial changes while aHUS and lupus nephritis showed both glomerular and arterial involvement. Postpartum TMA and aHUS had poor renal outcome requiring renal replacement therapy. Conclusion:Most postpartum TMA and aHUS had systemic features of TMA while malignant hypertension and lupus nephritis showed 'isolated renal TMA' . This emphasizes the importance of careful evaluation of renal biopsies even in the absence of systemic features of TMA.

Vascular Occlusion in Kidney Biopsy Is Characteristic of Clinically Manifesting Thrombotic Microangiopathy

“…Based on the literature it is unclear, if biopsy-proven TMA showing only histological features shares the same underlying etiology, prognosis, and clinical course than TMA with also clinical features. Most reports have compared different TMA subtypes (secondary HUS of various etiology, aHUS, typical HUS) [ 23 , 24 ] or reported findings in one subtype only [ 25 ], but none have reported comparisons based on the clinical scenario (h-TMA versus c-TMA). In a French retrospective report of 110 secondary HUS patients, kidney biopsy was performed in 46% of the patients.…”

“…However, it was not reported how many were only histological diagnoses [ 23 ]. In an Indian report of 33 native kidney TMA patients some hypertension and postpartum TMAs were reported to have only isolated arterial changes, but no further information was available [ 24 ]. In our report, it was evident that despite a somewhat better renal function in h-TMA patients at onset of the disease, kidney prognosis was, nevertheless, as poor in h-TMA as in c-TMA, because 27% of h-TMA patients needed chronic dialysis during follow-up compared to 33% in c-TMA.…”

A case of development of membranous nephropathy against the background of atypical hemolytic-uremic syndrome activated as a result of acute respiratory viral infection

“…Помимо типичных вариантов поражения почек, при аГУС возможны и более редкие формы в виде С3-гломерулопатий, которые являются самостоятельными проявлением наследственной патологии системы комплемента, но также в редких случаях могут быть в структуре клинических проявлений аГУС. Крайне редким является манифестация почечных проявлений в виде гломерулонефрита, не относящегося к категории С3-гломерулопатий или С3-доминантных форм [5]. Представляем клинический случай манифестации мембранозной нефропатии в рамках аГУС.…”

“…Также выявлены явления тубулоинтеристициального воспаления и фиброза с атрофией до 30% площади (рис. [1][2][3][4][5]. Отмечался слабо выраженный гипертрофический тип ремоделирования артерий мышечного и резистивного типов.…”