What the Internist Should Know about Thrombotic Microangiopathies

Thrombotic microangiopathy (TMA) is a group of diseases that are life-threatening and can lead to end organ damage (EOD) due to ischemia caused by microthrombi in capillaries and arterioles. TMAs can affect any organ system but usually affect the kidney, intestines, and nervous system. The triad of TMA is Coombs-negative hemolytic anemia with schistocytes seen on peripheral smear, thrombocytopenia (platelets under 150,000 or a decrease of 25% or more from baseline), and evidence of ischemic EOD. Primary TMAs include Thrombotic Thrombocytopenic Purpura (TTP), Hemolytic Uremic Syndrome (HUS) and atypical HUS (aHUS). Pathophysiologically, all of these diseases are caused by aggregation of von Willebrand Factor (vWF) multimers, via different mechanisms, which eventually leads to thrombus formation. TTP and aHUS benefit from plasma exchange (PEX), whereas HUS is treated symptomatically. Urgent recognition with timely treatment is crucial to managing these potentially life-threatening conditions.

Post-traumatic thrombotic microangiopathy: What trauma surgeons need to know?

Thrombotic microangiopathy(TMA)is characterized by systemic microvascular thrombosis,target organ injury,anemia and thrombocytopenia.Thrombotic thrombocytopenic purpura,atypical hemolytic uremic syndrome and Shiga toxin E-coli-related hemolytic uremic syndrome are the three common forms of TMAs.Traditionally,TMA is encountered during pregnancy/postpartum period,malignant hypertension,systemic infections,malignancies,autoimmune disorders,etc.Recently,the patients presenting with trauma have been reported to suffer from TMA.TMA carries a high morbidity and mortality,and demands a prompt recognition and early intervention to limit the target organ injury.Because trauma surgeons are the first line of defense for patients presenting with trauma,the prompt recognition of TMA for these experts is critically important.Early treatment of post-traumatic TMA can help improve the patient outcomes,if the diagnosis is made early.The treatment of TMA is also different from acute blood loss anemia namely in that plasmapheresis is recommended rather than platelet transfusion.This article familiarizes trauma surgeons with TMA encountered in the context of trauma.Besides,it provides a simplified approach to establishing the diagnosis of TMA.Because trauma patients can require multiple transfusions,the development of disseminated intravascular coagulation must be considered.Therefore,the article also provides different features of disseminated intravascular coagulation and TMA.Finally,the article suggests practical points that can be readily applied to the management of these patients.