title: Thrombotic thrombocytopenic purpura in the setting of systemic sclerosis.
abstract: OBJECTIVE
  To describe the association between thrombotic thrombocytopenic purpura (TTP) and systemic sclerosis (SSc) and the methods to distinguish TTP from scleroderma renal crisis (SRC).
  
  
  METHODS
  A case of TTP that developed in a patient with preexisting SSc is described. Medline/PubMed was searched for literature pertaining to an association between TTP and SSc, with special attention given to distinguishing TTP from SRC. In addition, the role of von Willebrand cleaving protease in the pathogenesis of TTP is reviewed.
  
  
  RESULTS
  Including the present case, there have been 9 reports of TTP in association with SSc in the literature. In the majority of these cases TTP presented with features compatible with SRC such as renal dysfunction, thrombocytopenia, hypertension, and microangiopathic hemolytic anemia. Von Willebrand cleaving protease activity is depressed in patients with acute TTP.
  
  
  CONCLUSIONS
  TTP in association with SSc has been reported rarely. The diagnosis of TTP, and the distinction from SRC, may be challenging, as these cases may resemble SRC. However, the correct diagnosis is critical because treatment differs substantially for each of these life-threatening conditions. Currently, the assessment of von Willebrand factor cleaving protease activity may assist in making this distinction.
authors.affiliation: Section of Rheumatology, Rush University Medical Center, Chicago, IL 60612, USA. amanadan@rush.edu
authors.forename: Augustine M
authors.initials: AM
authors.lastname: Manadan
authors.forename: Charlotte
authors.initials: C
authors.lastname: Harris
authors.forename: Joel A
authors.initials: JA
authors.lastname: Block
mesh_terms: D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis / Q000209:etiology; D008666:Metalloendopeptidases / Q000097:blood; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D012595:Scleroderma, Systemic / Q000150:complications*
chemical_list: D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human