[Thrombotic microangiopathy]

Abstract

Thrombotic microangiopathies (TMAs) are characterized by thrombocytopenia, microangiopathic hemolytic anemia, and organ failure (mostly renal dysfunction). TMA includes thrombotic thrombocytopenic purpura (TTP) with predominant neurological signs and hemolytic uremic syndrome (HUS) with predominant renal dysfunction, but they are often indistinguishable each other with the clinical signs alone. Recent availability of von Willebrand factor-cleaving protease or ADAMTS13 activity has defined that TTP is a syndrome frequently associated with a deficient ADAMTS13 activity with or without its inhibitors (autoantibodies), whereas HUS has almost the normal activity. Here, we present two cases of TMA, who were initially diagnosed as "multiple sclerosis" because of the fluctuated neurological signs. Case 1 was a 54-year-old male and case 2 was a 30-year-old female. During their clinical course, they accompanied thrombocytopenia, to which the etiology left undetermined in case 1, but case 2 was suspected DIC because she had such past history. Prophylactic infusion of platelet concentrates to both cases dramatically aggravated their clinical signs. Case 1 was diagnosed to be intravascular lymphoma complicated with acquired TTP, after showing a deficient ADAMTS13 activity. Case 2 was unable to assay ADAMTS13 activity, but later the autopsy revealed the presence of multiple hyaline membrane thrombosis in many organs, together with a lack of demyelinating lesions, solely confirming a diagnosis of TMA.