RT Book, Section
A1 Sadler, J. Evan
A2 Kaushansky, Kenneth
A2 Levi, Marcel
SR Print(0)
ID 1148373722
T1 Thrombotic Microangiopathies
T2 Williams Hematology Hemostasis and Thrombosis
YR 2017
FD 2017
PB McGraw-Hill Education
PP New York, NY
SN 9781260117080
LK hemonc.mhmedical.com/content.aspx?aid=1148373722
RD 2024/04/16
AB SUMMARYThrombotic  microangiopathy  is  a  general  term  for  the  combination  of  micro­angiopathic  hemolytic  anemia  and  thrombocytopenia,  often  accompanied  by  signs  and  symptoms  consistent  with  disseminated  microvascular  thrombosis.  Thrombotic  thrombocytopenic  purpura  (TTP)  refers  to  thrombotic  micro­angiopathy,  without  an  obvious  predisposing  condition,  and  without  oliguric  renal  failure.  TTP  is  caused  by  autoantibodies  to  ADAMTS13  (a  disintegrin  and  metalloprotease  with  a  thrombospondin  type  1  motif  member  13),  a  plasma  metalloprotease  that  normally  cleaves  von  Willebrand  factor  (VWF)  and  regulates  VWF-dependent  platelet  aggregation.  Inherited  deficiency  of  ADAMTS13  causes  congenital  TTP,  which  typically  responds  to  plasma  infusion.  Most  patients  with  acquired  TTP  respond  to  plasma  exchange,  although  many  have  relapsing  disease.  Hemolytic  uremic  syndrome  (HUS)  refers  to  thrombotic  microangiopathy  that  usually  causes  oliguric  or  anuric  renal  failure.  Ingestion  of  Shiga  toxin–producing  Escherichia  coli  can  cause  the  most  common  or  “typical”  form  of  HUS  that  is  usually  preceded  by  bloody  diarrhea.  Inherited  or  acquired  defects  in  the  regulation  of  the  alternative  complement  pathway  cause  HUS  referred  to  as  “atypical”  because  it  occurs  without  a  prodrome  of  bloody  diarrhea.  Secondary  thrombotic  microangiopathy  can  occur  in  association  with  metastatic  cancer,  infections,  organ  transplantation,  and  certain  drugs.  These  variants  of  thrombotic  microangiopathy  differ  in  pathogenesis  and  prognosis  but  can  be  difficult  to  distinguish  because  their  clinical  features  often  overlap.