Abstract: PUB175
An Elusive Case of Renal Failure in a Patient with Atypical Hemolytic Uremic Syndrome
Session Information
Category: Trainee Case Report
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Portugal, Frank A., Robert Wood Johnson University Hospital, New Brunswick, New Jersey, United States
- Ahmed, Ayesha, Robert Wood Johnson University Hospital, New Brunswick, New Jersey, United States
Introduction
AHUS is microangiopathic hemolysis, thrombocytopenia, and AKI with normal ADAMTS13 and absence of STEC. It involves activation of complement via alternative pathway causing TMA with end-organ involvement. Causes can be complement regulation deficits, infections, and drugs. Here is a rare case of AHUS after a C.difficile infection, requiring dialysis.
Case Description
19-year-old man with OSA, ADHD, and obesity had a 3-week course of diarrhea and fever. Cr was 2.15, platelet 143, and tested + for C.diff and was on po vanco then flagyl. Given worsening symptoms, he went to the ER and Hb was 13.9, platelets 24, WBC 14.8, BUN 130 and Cr 8.4. He had low complements (C4 <7.9, C3 46.2), few schistocytes on peripheral smear, mildly elevated LDH and high-normal haptoglobin. He began dialysis, plasmapheresis and had a renal biopsy. Imaging showed splenomegaly (15-20 cm) and lymphadenopathy (negative BM and lymph node biopsy). ADAM13 level was 50 and plasmapheresis was stopped. Further infectious and autoimmune workup was negative. Renal biopsy showed a TMA process and C5b-9 staining was positive in the glomerulus and arteriolar vessels. Serum C5b-9 level was elevated (343). A genetics panel showed no variant associated with AHUS nor predisposition to poor response to eculizumab. He was discharged with eculizumab maintenance and dialysis. Recently, his labs improved with a Cr of 1.5 and platelets of 163.
Discussion
Here, typical features of hemolysis were missing, and diagnosis was made on renal biopsy with findings of TMA and + C5b-9 stain. Ongoing understanding of causes for AHUS include hereditary (complement and DGKE gene mutations) and acquired (infection, autoantibodies to complement, drug toxicity and autoimmune). Although genetic panel was negative, it cannot be ruled out as genetic mutations are only identified in 50-70% of cases. Shiga-toxin and pneumococcal-HUS are causes, but here we found rare C.difficile-induced cause. Patient was successfully treated with eculizumab. Thus, AHUS is elusive and clinically challenging in diagnosis.