Thrombotic microangiopathy and indications for therapeutic plasma exchange

Abstract

Thrombotic microangiopathy (TMA) is a clinicopathological condition associated with a wide variety of medical conditions. TMA is classically characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular thrombi that cause end-organ damage. The most prominent diagnoses associated with TMA are thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Although TTP and HUS can have similar clinical and laboratory features and are often lumped together as a combined entity referred to as "TTP/HUS," the pathologic processes causing TMA and optimal therapies for these conditions are different. Empiric use of therapeutic plasma exchange (TPE) in the setting of TMA is common. The high risk of morbidity and mortality associated with some causes of TMA justify rapid institution of this relatively low-risk procedure. However, many causes of TMA do not respond to TPE and prolonged courses of exchange in the absence of an underlying diagnosis may cause a detrimental delay in appropriate medical therapy. The American Society of Apheresis has published guidelines for the use of TPE for several distinct conditions associated with TMA. This list is not comprehensive and the use of TPE for other causes of TMA may be considered if the mechanism of the underlying disease process provides a clear rationale for this intervention. Learning Objective• To acquire information and clinical tools to augment clinical judgement regarding the use of TPE in the setting of TMA

A single‐center prospective study on the safety of plasma exchange procedures using a double‐viral‐inactivated and prion‐reduced solvent/detergent fresh‐frozen plasma as the replacement fluid in the treatment of thrombotic microangiopathy

“…While there is common consensus that therapeutic PEX is the treatment of choice for acute TMAs, there remains discussion over the exchange plasma fluid of choice . Plasma reactions and viral or pathogen transmission are the two main risks .…”

Modified Ham test for atypical hemolytic uremic syndrome

“…TTP diagnosis was made in patients with relevant clinical features (microangiopathic hemolytic anemia and thrombocytopenia) and ADAMTS13 #10%. 31 DIC was diagnosed in patients with thrombocytopenia, elevated d-dimers, low fibrinogen, prolonged clotting time, and underlying disorders associated with DIC, matching the International Society on Thrombosis and Haemostasis diagnostic criteria. 32 Final diagnosis, course, and patient treatment were recorded.…”

Prognostic risk‐stratified score for predicting mortality in hospitalized patients with thrombotic thrombocytopenic purpura: nationally representative data from 2007 to 2012

“…Thrombotic thrombocytopenic purpura (TTP) is a clinicopathologic entity presenting as a severe thrombotic microangiopathy (TMA) characterized by red blood cell (RBC) fragmentation, profound thrombocytopenia, fever, renal failure, and neurologic involvement of variable severity due to microvascular thrombosis with tissue ischemia and infarction . While TTP symptoms are classically defined as this pentad, many clinicians suspect TTP in patients with thrombocytopenia, microangiopathic hemolytic anemia, and elevated lactate dehydrogenase .…”

“…While it is widely recognized and accepted that TTP still has a high risk for in‐hospital morbidity and mortality, recent estimates of all‐cause mortality in hospitalized TTP patients are not available. Additionally, survivors of TTP hospitalizations have been proposed to be at higher risk for long‐term poor clinical outcomes and eventual premature death .…”