#2989 Superposition of atypical hemolytic syndrome and tubulointerstitial nephritis, a case report

Abstract

Abstract Background and Aims Hemolytic uremic syndrome is a heterogeneous group of diseases that have in common the development of thrombotic microangiopathy with diffuse endothelial damage, resulting in the classic triad composed of microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury, on the other hand, tubulointerstitial nephritis is characterized by the presence of inflammatory infiltrates and edema and of the interstitial compartment that causes deterioration of renal function. Method The following is the case of a patient with acute kidney injury of etiology composed of thrombotic microangiopathy and tubulointerstitial nephritis. Results 27-year-old female patient without significant history, began 3 weeks prior to admission with fever, chills, asthenia, nausea and vomiting of food content, approximately 5 episodes per day for 3 days, presenting intermittent episodes of jaundice of the mucous membranes and conjunctivae, with progressive increase of the symptoms to the point of preventing daily activities, she was admitted for study, detecting hemolytic anemia, thrombocytopenia and severe acute kidney injury, so she was referred to our center was decided for evaluation by Nephrology and Hematology. In our institution, urinary sediment with dysmorphic erythrocytes was documented, peripheral blood smear without the presence of schistocytes, positive Coombs 4 crosses, renal ultrasound with data compatible with acute kidney injury, and supportive management with hemodialysis was initiated. Due to suspicion of autoimmune glomerulopathy, an autoantibody panel was indicated with negative antinuclear antibodies, anti-double-stranded DNA, anti-Sm, anti-B2 glycoproteins, and lupus anticoagulant, with normal complement values, stool culture, and negative stool Shiga protein assay, angiotomography of the abdomen where the integrity of renal circulation is verified, so renal biopsy with immunohistochemical study is performed, finding data compatible with thrombotic microangiopathy and acute tubulointerstitial nephritis. The patient is maintained with supportive care, steroids and hemodialysis as required with progressive recovery of renal function until renal replacement therapy is weaned, she is discharged with a steroid regimen and clinical nephrology and hematology follow-up. Conclusion Acute kidney injury is a complex and multifactorial entity, which requires a comprehensive approach in order to identify the best therapeutic option and to offer a better outcome in the renal function of these patients. The case of our patient presented a sudden deterioration of renal injury composed of two entities with different pathophysiology, demonstrating that, although the approach to these two entities converge in certain etiologies, it is imperative that the clinician does not forget the wide variety of factors that contribute to the development of renal injury.