(509) A Case of Thrombotic Thrombocytopenic Purpura and Catastrophic Antiphospholipid Syndrome Overlap

Introduction: Hematologic emergencies in the ICU can be life-threatening with high mortality rates. We present a rare case of thrombotic thrombocytopenic purpura (TTP) and catastrophic antiphospholipid syndrome (CAPS).

Description: A 62-year-old male with a history of hyperlipidemia, diabetes, and untreated systemic lupus erythematosus (SLE) presented with a week-long right-sided facial droop. Initial evaluation in the ED revealed pancytopenia (hemoglobin 8.1, WBC 3.7, platelet 11), low haptoglobin, elevated LDH, and schistocytes on blood smear. Non-contrast CT head showed no acute intracranial bleed, but elevated high-sensitivity troponin was noted.
An MRI of the brain identified an acute lacunar infarct in the right cerebellum. The patient's condition continued to deteriorate becoming more encephalopathic and he was transferred to ICU. Repeat MRI revealed a new left posterior cerebellar and right occipital lacunar infarct. He was initially treated with IVIG and pulse dose steroids.
ADAMTS13 activity was ultimately found to be < 2% with positive ADAMTS13 antibodies, confirming TTP. Concurrently, anti-phospholipid (aPL) antibodies including anti-cardiolipin, Beta-2 glycoprotein, and lupus anticoagulant were also positive with low C3 and C4 levels confirming CAPS. A bone marrow biopsy was performed with a negative flow cytometry. A venous duplex revealed a left lower extremity thrombus.
The patient was ultimately treated with eight sessions of plasmapheresis with recovery of his pancytopenia. There are plans to transition the patient to Rituximab and oral anticoagulation life-long.

Discussion: TTP and Antiphospholipid syndrome (APS) are two very separate disease processes. TTP presents with the usual triad of microangiopathic anemia, thrombocytopenia, and renal failure. CAPS, an unusual but deadly presentation of APS, is characterized by multi-organ failure secondary to thrombosis. There have been reports of a high prevalence of ADAMST13 dysfunction/antibodies in patients with APS. It is important to know that this association exists. Nonetheless, the acute treatment for these two diseases are very similar.