Thrombotic microangiopathy in childhood steroid-resistant nephrotic syndrome - case series.

INTRODUCTION: Thrombotic microangiopathy (TMA) with associated nephrotic syndrome is a unique and rare condition that is infrequently described in pediatrics. CASE PRESENTATIONS: Four children with steroid-resistant nephrotic syndrome (SRNS), immune-mediated and of monogenic origin, presented with TMA during late stages of chronic kidney disease. All patients tested negative for shigatoxin and had normal A Disintegrin-like and Metalloprotease with Thrombospondin type 1 repeats 13 (ADAMTS13) activity. Genetic and functional studies of complement dysregulation were negative. Three of the four patients treated with Eculizumab showed good hematologic response but no kidney function recovery. None of the three children who underwent kidney transplantation had recurrent TMA. CONCLUSIONS: TMA may develop in patients with SRNS, manifesting as an unexplained worsening of kidney function, new-onset hypertension, hemolytic anemia, and thrombocytopenia. Eculizumab was effective in improving hemolytic markers without kidney function recovery. TMA did not recur after kidney transplantation in this entity.