Abstract: FR-PO0440
Dialysis-Requiring Thrombotic Microangiopathy and Catastrophic Antiphospholipid Syndrome After Avatrombopag Exposure
Session Information
- AKI: Case Reports - TMA, Vasculitis, Immune-Mediated Injury, and Systemic Disease
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Sola - Oladokun, Babasola, Cork University Hospital, Cork, County Cork, Ireland
- O'Connell, Blathnaid, Cork University Hospital, Cork, County Cork, Ireland
- Mayer, Nick, Cork University Hospital, Cork, County Cork, Ireland
- Clarkson, Michael, Cork University Hospital, Cork, County Cork, Ireland
- Crowley, Maeve P., Cork University Hospital, Cork, County Cork, Ireland
- Moran, Sarah Margaret, Cork University Hospital, Cork, County Cork, Ireland
Introduction
Thrombopoietin receptor agonists are increasingly used in refractory immune thrombocytopenia but carry thrombotic risk. Catastrophic antiphospholipid syndrome is a rare, life-threatening disorder characterized by rapidly progressive multiorgan small-vessel thrombosis. We describe dialysis-dependent acute kidney injury due to biopsy-proven thrombotic microangiopathy shortly after avatrombopag initiation.
Case Description
A 38-year-old woman with refractory ITP, epilepsy, bipolar affective disorder, and prior steroid-induced psychosis presented 11 days after starting avatrombopag with flu-like symptoms, chest pain, dyspnea, headache, and seizures. Baseline creatinine was 72 μmol/L, rising to 767 μmol/L with thrombocytopenia, LDH 1640 U/L, troponin 1312 ng/L, NT-proBNP 133,318 pg/mL, hematuria, and proteinuria. Refractory hyperkalemia required hemodialysis.
Autoimmune testing demonstrated persistent anticardiolipin antibody positivity, positive dilute Russell viper venom testing, and elevated beta-2 glycoprotein antibodies. ANA, ANCA, anti-dsDNA, anti-GBM antibodies, and complement levels were normal.
Kidney biopsy demonstrated severe acute vascular and glomerular TMA with endothelial swelling, fibrinoid necrosis, occlusive and focal cortical necrosis with minimal chronic damage. Immunofluorescence was negative.
Echocardiography demonstrated pulmonary hypertension.
A diagnosis of CAPS was established based on rapidly progressive renal, neurologic, and cardiac involvement, biopsy-confirmed TMA, and persistent antiphospholipid antibody positivity. Avatrombopag was considered the likely trigger given the close temporal relationship with symptom onset.
Treatment included pulse methylprednisolone, IVIg, rituximab, anticoagulation, and renal replacement therapy. Dialysis was discontinued after approximately nine weeks with recovery of kidney function and improvement in cardiac function.
Discussion
This case highlights CAPS presenting with renal TMA and dialysis-dependent kidney failure following avatrombopag exposure. While thrombotic complications are recognized with TPO-RAs, CAPS is exceptionally rare. CAPS should be considered in patients with rapidly progressive multiorgan dysfunction and TMA after prothrombotic triggers. Kidney biopsy is critical in establishing the diagnosis, and recovery of kidney function is possible despite prolonged renal replacement therapy.