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Complement activation: an atypical presentation of an atypical syndrome
  1. Alfredo Iardino1,
  2. Viviane Bunin2,
  3. Luan D Truong3,
  4. Hector Alejandro Preti4
  1. 1Internal Medicine, Texas Tech University at the Permian Basin, Odessa, Texas, USA
  2. 2Rheumatology, Houston Methodist Hospital, Houston, Texas, USA
  3. 3Department of Pathology, Houston Methodist Hospital, Houston, Texas, USA
  4. 4Medical Oncology, Houston Methodist Hospital, Houston, Texas, USA
  1. Correspondence to Dr Alfredo Iardino, alfredo.iardino{at}


A 42-year-old Hispanic female and long-distance runner was seen for evaluation of fatigue. Her physical examination showed petechiae and ecchymoses in upper extremities, abdominal distension and bilateral ankle oedema. Laboratory workup revealed anaemia, thrombocytopenia, hypoalbuminemia and proteinuria of 1.4 g/24 hours. No schistocytes were found on peripheral blood smear. CT of her abdomen revealed diffuse small lymphadenopathy and hepatomegaly. Bone marrow biopsy demonstrated normal trilineage hematopoiesis with no hemophagocytosis. The patient was started on oral prednisone with no improvement and was subsequently admitted to the hospital for pulsed steroids, intravenous immunoglobulin and rituximab. Her proteinuria became nephrotic range, and a renal biopsy revealed features of thrombotic microangiopathy limited to the glomerular capillaries. ADAMTS13 was low which is >10% of normal, and a diagnosis of atypical haemolytic–uraemic syndrome (aHUS) was made. Eculizumab was started with prompt response. Whole exome sequencing demonstrated mutation in SPTA1, which has been associated with red blood cell membrane diseases but has not been described in patients with aHUS.

  • acute renal failure
  • nephrotic syndrome
  • proteinurea
  • haematology (drugs and medicines)
  • malignant and benign haematology

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  • Contributors AI: design and writing of the manuscript, data gathering, clinical analysis, graphic creation, patient follow up interview, communication with genetic lab and bibliographic review. VB: General review of the manuscript and chart review. LDT: pathology slides review, bibliographic collection, pathology images design and explanation. HAP: general review of the manuscript, final and continuous editing, medical care of the patient, bibliographic review and data interpretation.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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