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[Thrombotic microangiopathy]
1Department of Blood Transfusion Medicie, Nara Medical University.
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.
Insights
Thrombotic microangiopathies (TMAs) can mimic neurological disorders, leading to misdiagnosis. Prompt identification and ADAMTS13 activity testing are crucial for accurate TMA diagnosis and effective treatment.
Area of Science:
- Hematology
- Neurology
- Pathology
Background:
- Thrombotic microangiopathies (TMAs) encompass thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), presenting with thrombocytopenia, microangiopathic hemolytic anemia, and organ dysfunction.
- Distinguishing TTP and HUS clinically is challenging due to overlapping symptoms, particularly neurological and renal manifestations.
- ADAMTS13 activity assays are pivotal in differentiating TTP (low activity) from HUS (normal activity).
Observation:
- Two cases of TMA were initially misdiagnosed as multiple sclerosis due to fluctuating neurological signs.
- Both patients developed thrombocytopenia, and platelet concentrate infusions exacerbated their conditions.
- Case 1 was diagnosed with intravascular lymphoma and acquired TTP, confirmed by deficient ADAMTS13 activity.
Findings:
- Case 2, despite suspected disseminated intravascular coagulation (DIC), ultimately received an autopsy-confirmed TMA diagnosis.
- Autopsy in Case 2 revealed widespread hyaline membrane thrombosis and absence of demyelinating lesions.
- The study highlights the diagnostic challenges and potential pitfalls in managing TMA patients.
Implications:
- TMAs can present with neurological symptoms mimicking primary neurological diseases, necessitating a broader differential diagnosis.
- The adverse effect of platelet transfusions in TMA underscores the importance of accurate diagnosis before intervention.
- Accurate and timely diagnosis of TMA, supported by ADAMTS13 testing, is critical for appropriate patient management and improved outcomes.
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