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2009 年一般醫學系臨床病理討論會. Clinical Pathology Conference 討論篇. 報告者:第 年住院醫師. Hospital course. PB smear Anisocytosis: 3+ Microcytosis: 1+ Chromic: normochromic Fragmented RBC: found Hemolytic anemia was confirmed - PowerPoint PPT Presentation
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2009年一般醫學系臨床病理討論會
Clinical Pathology Conference 討論篇
報告者:第 年住院醫師
Hospital course PB smear
Anisocytosis: 3+ Microcytosis: 1+ Chromic: normochromic Fragmented RBC: found
Hemolytic anemia was confirmed unconjugated hyperbilirubinemia, nucleated
red cells, increased RDW, anisocytosis, fragmented RBC
Hospital course Summary of abnormality
1. Thrombocytopenia2. Conscious disturbance3. Hemolytic anemia
Three of the pentad of thrombotic thrombocytopenic purpura (TTP) was matched
No other feasible diagnosis can explain all the abnormality
Hospital course Plasmaphoresis was arranged Dexamethasone was given Empiric antibiotics was prescribed because of
fever up to 38.4℃ after admission Two days after admission, an episode of
generalized-tonic-clonic seizure occurred. Diazepam and phenytoin were used. The CT of brain was arranged and there was no intracranial hemorrhage
Hospital course Her conscious level didn’t improve after all this
therapeutic management Bradycardia then asystole occurred at the
second hospital day. Cardiopulmonary resuscitation was performed but failure.
Thrombotic thrombocytopenic purpura (TTP)
Potentially fatal disordercharacterized by platelet aggregates in
microvasculature vessel occlusion tissue ischemia and end-organ damage
Male: female ratio of 1: 2Prompt diagnosis is mandatory
so emergency treatment can be instituted immediately
Current Opinion in Neurology. 2003;16:367-73,
Hematol Oncol Clin North Am. 2003;17: 177-99, .
Etiology and precipitating factor Pregnancy Drugs
e.g. ticlopidine, clopidogrel, oral contraception, cyclosporin, mitomycin C and quinine
Autoimmune disorders such as SLE
Infection particularly HIV, toxigenic strains of Shigella and
Escherichia coli Post bone marrow or solid organ transplantation Post coronary artery bypass graft- 13 cases reported
W V Med J.2004; 100(2): 64-6.
Pathophysiology
von Willebrand factor (vWF) endothelial cells and megakaryocytes normally
make monomers of vWF that are joined to form larger vWF multimers
Under normal conditions, vWF-cleaving metalloprotease (ADAMTS13) cleaves these multimers
Clinical and laboratory features
Classical pentad (complete pentad< 30%) Thrombocytopenia (platelet count < 20×103) Microangiopathic hemolytic anemia (MAHA) Neurologic impairment (63-70%) Renal impairment (59%) Fever
Chest pain, abdominal pain
Clinical and laboratory features
RBC fragmentation (schistocytes) ↑ Reticulocyte (increased RBC turnover) ↓ Haptoglobin (binding to free Hb) ↑ LDH (hemolysis, ischemic organs)
Renal or liver impairment (representing ischemic organs)
↑ Unconjugated (indirect) bilirubin
DAT (direct Coombs test) negative Normal coagulation studies
Treatment
Plasma exchange (mainstay of therapy ) Superior to plasma infusion Instituted within 24h of presentation 1.0-1.5 plasma volume exchanges qd (40 mL/kg) LDH, usually used as a day-to-day indicator of the
severity of hemolysis, along with Hb value and reticulocyte count
In the Canadian Apheresis Trial, complete remission is defined as normalization of platelet count for 2 consecutive days with no deterioration in neurological status
Treatment
Cryosupernatant (cryoprecipitate-poor plasma) lacking vWF at least as effective as FFP
Adjunctive therapy Corticosteroids
methylprednisolone 1g IV qd, or prednisolone 1mg/kg PO qd
Antiplatelet agents aspirin and dipyridamole not accepted universally, and might exacerbate
the risk of bleeding
RBC transfusion as needed
Contraindications Platelet transfusions Desmopressin (DDAVP)
releasing vWF from the endothelial cells into blood
Refractory TTP and Immunosuppressive therapies
Vincristine (Immunosupression) case reports or small retrospective studies
Rituximab (anti-CD20 Ab) first use in recent reports
Splenectomy removal of the B cells responsible for the
production of autoantibodies inhibiting ADAMTS13