Collapsing glomerulopathy is common in the setting of thrombotic microangiopathy of the native kidney.

Thrombotic microangiopathy (TMA) is a poorly recognized cause of collapsing glomerulopathy. The frequency and significance of collapsing glomerulopathy associated with renal TMA have not been specifically studied in native kidney biopsy specimens. Here we retrospectively documented clinicopathologic features of 53 patients with histologically proven TMA in the native kidney, with special emphasis on changes due to focal segmental glomerulosclerosis (FSGS). Histological TMA was related to hypertensive nephropathy in 21 patients, genetic complement abnormalities in 9, drugs in 7, and to other causes in 16 patients. Almost half (26 patients) presented with arteriolar, 6 with glomerular, and 21 with mixed TMA. Using the Columbia classification system for the 53 patients with histological TMA, 33 had concurrent FSGS lesions with collapsing glomerulopathy the dominant variant in 19 patients (58% of the FSGS cases), not otherwise specified in 9 patients, cellular in 3, and perihilar or tip lesions in 1 patient each. The presence of FSGS was associated with a poor renal prognosis, with no prognostic difference between collapsing glomerulopathy and other FSGS variants. Thus, collapsing glomerulopathy is frequently found in native kidney biopsies with TMA, suggesting that endothelial injury may play an important role in the pathophysiology of FSGS.

Renal Cortical Necrosis in Postpartum Hemorrhage: A Case Series.

BACKGROUND: Pregnancy-related renal cortical necrosis may lead to end-stage renal disease. Although this obstetric complication had virtually disappeared in high-income countries, we have noted new cases in France over the past few years, all following postpartum hemorrhage. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: We retrospectively identified 18 patients from 5 French nephrology departments who developed renal cortical necrosis following postpartum hemorrhage in 2009 to 2013. OUTCOMES: Obstetric and renal features, therapeutic measures, and kidney disease outcome were studied. RESULTS: All patients had a severe postpartum hemorrhage (mean blood loss, 2.6±1.1 [SD] L). Hemodynamic instability and disseminated intravascular coagulation were reported in 5 and 11 patients, respectively. All developed rapid onset of acute kidney injury and required hemodialysis. Diagnosis of renal cortical necrosis was performed 4 to 33 days following delivery. At 6 months postpartum, 8 patients remained dialysis dependent and none recovered normal kidney function. The length of exposure to tranexamic acid treatment was significantly more prolonged in women whose estimated glomerular filtration rate remained <15mL/min/1.73m(2) (7.1±4.8 vs 2.9±2.4 hours; P=0.03). LIMITATIONS: Retrospective study; small sample size. CONCLUSIONS: In the setting of gravid endothelium, the conjunction of disseminated intravascular coagulation with the life-saving use of procoagulant and antifibrinolytic agents (recently implemented in France in a postpartum hemorrhage treatment algorithm) may give rise to a risk for uncontrolled clotting in the renal cortex and hence irreversible partial or diffuse cortical necrosis.