Kidney Week

Abstract: PUB458

Spontaneous Improvement Without Therapy in a Patient with Atypical Hemolytic Uremic Syndrome with p. I1157T in the C3 Gene Triggered by Influenza B Infection: A Case Report

Session Information

• Publication Only

Category: Trainee Case Report

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Yamazaki, Satoshi, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Satoshi Yamazaki,

• Matsumura, Hideki, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Hideki Matsumura,

• Fujii, Yuko, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Yuko Fujii,

• Tanaka, Tomoko, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Tomoko Tanaka,

• Shirasu, Akihiko, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Akihiko Shirasu,

• Nakakura, Hyogo, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Hyogo Nakakura,

• Sugawara, Yuka, The University of Tokyo, Tokyo, Japan

Yuka Sugawara,

• Yoshida, Yoko, The University of Tokyo, Tokyo, Japan

Yoko Yoshida,

• Ikeda, Yoichiro, The University of Tokyo, Tokyo, Japan

Yoichiro Ikeda,

• Ashida, Akira, Osaka Medical College, Takatsuki, OSAKA-FU, Japan

Akira Ashida,

Introduction

Atypical hemolytic uremic syndrome (aHUS) is a severe systemic disease characterized by thrombocytopenia, hemolytic anemia, and acute kidney injury. It has a poor prognosis, and the mortality rate was as high as 25% before the introduction of eculizumab therapy. In 50-80% of patients, an infectious event triggers the onset of aHUS. Among such triggers, influenza infection is relatively common, but most cases are of the H1N1 type or influenza A, and influenza B is only very rarely responsible.

Case Description

The patient was a 15-year-old boy who presented with a 2-day history of fever and macrohematuria, but no diarrhea. A nasal swab demonstrated positivity for influenza B virus antigen. On admission, he showed hemolysis with red blood cell fragmentation in a blood smear (LDH 1478 U/L, haptoglobin 6 mg/dL, Hb 13.8 g/dL), thrombocytopenia (17x10³/μL) and acute kidney injury (serum creatinine 0.95 mg/dL) The serum creatinine level improved to 0.63 mg/dL in the recovery phase on day 11 after admission, and therefore the acute kidney injury was diagnosed as AKI stage 1 by KDIGO. These findings suggested incomplete TMA. ADAMTS13 activity was normal and a stool culture test failed to identify Shiga toxin-producing Escherichia coli or Shiga toxin 1 and 2. As manifestations such as hemolytic anemia and acute kidney injury were mild, the patient received peramivir hydrate for influenza B infection without plasma therapy or eculizumab therapy. He recovered and was discharged with no sequelae on hospital day 7. No relapse was observed for over 1 year. Subsequent genetic analysis identified mutation in C3 (p.I1157T), confirming a diagnosis of aHUS.

Discussion

The symptoms in the present case were mild and improved spontaneously without specific therapy including plasma exchange or eculizumab. Japanese patients with C3 p.I1157T mutation, which was identified in this case are reported to show a favorable prognosis, and spontaneous recovery of an aHUS patient with MCP mutation triggered by influenza B has been documented. The data suggest that a mild defect of complement regulation including C3 p.I1157T resulted in the present patient’s mild aHUS symptoms.