Thrombotic microangiopathies (TTP, HUS, HELLP)

Emerg Med Clin North Am. 2014 Aug;32(3):649-71. doi: 10.1016/j.emc.2014.04.008. Epub 2014 Jun 3.


Thrombocytopenia, strictly defined as a platelet count less than 150,000, is common in the emergency department. Recognition, diagnostic investigation, and proper disposition of a thrombocytopenic patient are imperative. One group of disorders leading to thrombocytopenia is the thrombotic microangiopathies, hallmarked by platelet destruction. These thrombotic microangiopathies include thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS) and hemolysis, elevated liver enzyme levels, low platelet count (HELLP), which should be distinguished from similar disease processes such as immune thrombocytopenia (ITP), disseminated intravascular coagulation (DIC) and heparin induced thrombocytopenia (HIT). In this article, clinical presentations, pathophysiology, diagnostic workup, management plans, complications, and dispositions are addressed for this complex group of platelet disorders.

Keywords: DIC; HELLP; HUS; Hemolytic anemia; ITP; Microangiopathies; TTP; Thrombocytopenia.

Publication types

  • Review

MeSH terms

  • Adult
  • Child
  • Female
  • HELLP Syndrome / diagnosis
  • HELLP Syndrome / therapy
  • Hemolytic-Uremic Syndrome / diagnosis
  • Hemolytic-Uremic Syndrome / therapy
  • Humans
  • Immunosuppressive Agents / therapeutic use
  • Pregnancy
  • Purpura, Thrombotic Thrombocytopenic / diagnosis
  • Purpura, Thrombotic Thrombocytopenic / therapy
  • Thrombocytopenia / etiology
  • Thrombotic Microangiopathies / diagnosis*
  • Thrombotic Microangiopathies / etiology
  • Thrombotic Microangiopathies / therapy


  • Immunosuppressive Agents