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Abstract: FR-PO681

A Case of Proteinuria Associated With Thrombotic Microangiopathy in a Patient With Sickle Cell Disease

Session Information

Category: Glomerular Diseases

  • 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials

Authors

  • Pasricha, Sachin V., University Health Network, Toronto, Ontario, Canada
  • Ward, Richard, University Health Network, Toronto, Ontario, Canada
  • Patriquin, Christopher J., University Health Network, Toronto, Ontario, Canada
  • John, Rohan, University Health Network, Toronto, Ontario, Canada
  • Malavade, Tushar Suryakant, University Health Network, Toronto, Ontario, Canada
Introduction

Thrombotic microangiopathy (TMA) causes renal dysfunction. Classic causes include thrombotic thrombocytopenic purpura, atypical haemolytic uremic syndrome, pregnancy, malignancy, drugs, transplant, autoimmune disease, infection, malignant hypertension, antiphospholipid (APLA) syndrome. We describe the case of patient with SCD with TMA shown on renal biopsy when evaluated for proteinuria.

Case Description

A 25 year-old male with SCD (HbSS) had proteinuria (1+ on dipstick, urine PCR of 212 mg/mmol, 24-hour protein of 2.75 g) with normal renal function (creatinine 83µmol/L) on screening. He had no known renal disease, diabetes, or nephrotoxic medications (including no NSAIDs). Routine blood-work was unremarkable, aside from baseline haemolytic indices. Autoimmune, vasculitis and infectious workup was negative. Morphological review was done to confirm schistocytes were not being mistaken for sickled RBC.

Renal biopsy showed changes suggestive of SCN/hypertension (Fig 1a), and TMA (Fig 1b). Work-up for TMA causes was negative - normal ADAMTS13 levels (>98%), negative blood cultures, and no APLA antibodies. Genetic studies did not show any TMA pathogenic variants in complement or coagulation genes. The TMA was thus attributed to SCD in the absence of acute pain episodes.

Discussion

Case reports describe SCD-associated TMA, but these are in the setting of vaso-occlusive pain episodes, which are hypothesized to trigger TMA. Our case of SCD-associated TMA, without a pain crisis, is thus novel and proposes that SCD itself may be a secondary cause of renal TMA.

Our case highlights the importance of renal biopsy for patients with SCD and proteinuria to identify if entities aside from SCN are contributory. Patients with SCD-associated TMA have responded to plasma exchange and/or RBC exchange transfusion in the setting of a pain crisis. Whether patients like ours, presenting outside a pain crisis, also respond to these therapies remains to be studied.