A 45-year-old female is admitted to the Intensive Care Unit (ICU) with confusion, fever, and petechial rash. She has a history of fatigue, easy bruising, and intermittent abdominal pain over the past two weeks. On physical examination, she is febrile (38.5°C), hypotensive (BP: 95/60 mmHg), and tachycardic (HR: 120 bpm). She has scattered petechiae on her extremities and mild scleral icterus. Initial laboratory findings reveal severe thrombocytopenia (platelet count: 12,000/µL), microangiopathic hemolytic anemia (hemoglobin: 7.5 g/dL with schistocytes seen on blood smear), elevated lactate dehydrogenase (LDH), and normal coagulation parameters. Renal function tests show acute kidney injury (creatinine: 3.2 mg/dL), and a urine dipstick is positive for hemoglobin without red blood cells on microscopy. The clinical presentation and lab findings strongly suggest a diagnosis of thrombotic thrombocytopenic purpura (TTP). The patient is immediately started on plasma exchange therapy along with corticosteroids. Due to significant renal impairment, continuous renal replacement therapy (CRRT) is initiated concurrently to manage fluid overload and electrolyte imbalances. The ICU team discusses the therapeutic goals and complications associated with TTP and the rationale for the chosen interventions.
Wrong Answer: A. To remove excess fluid from the body. This is incorrect. Plasma exchange therapy is not primarily aimed at removing excess fluid. While CRRT can manage fluid overload, plasma exchange focuses on addressing the underlying pathophysiology of TTP.
Right Answer:B. To remove autoantibodies and replenish ADAMTS13 enzyme. This is correct. The primary purpose of plasma exchange in TTP is to eliminate circulating autoantibodies against ADAMTS13 and supply fresh plasma, which contains the deficient ADAMTS13 enzyme. This reduces microvascular thrombosis and halts disease progression.
Clinical Pearls:
Wrong Answer:C. To provide long-term renal replacement therapy. This is incorrect. Plasma exchange is a short-term intervention targeting TTP pathophysiology. CRRT supports renal function temporarily but is not a long-term solution for kidney injury.
Wrong Answer: D. To promote clot formation in major organs. This is incorrect. The goal of therapy is to prevent further clot formation in small vessels, not to promote clotting. The condition itself involves excessive clotting, which treatment aims to control.
