MEDI: Microangiopathic Hemolytic Anemia

Semester 3
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What is microangiopathic hemolysis?
Intravascular and has RBC fragmentation actively occurring as cause of hemolysis
- caused by factors in the small blood vessels
What can you see in a RBCs in peripheral blood smear in microangiopathic hemolysis?
-schistocytes
-fragements
-burr cells
-microspherocytes
What are some causes of microangiopathic hemolytic anemia?
-malignant hypertension
-thrombotic thrombocytopenic purpura-hemolytic uremic syndrome
-Hemolytic uremic syndrome (HUS)
-Disseminated intravascular coagulation (DIC)
-HELLP syndrome in preggos
What are the 5 classic manifestation of thrombotic thrombocytopenic purpura?
-purpura
-MAHA
-neurologic events
-renal abnormalities
-Fever
What is thrombotic thrombocytopenic purpura?
typically microangiopathic hemolytic anemia and thrombocytopenia
-extensive microscopic clots to form in the small blood vessels throughout the body
What causes TTP?
-functional loss of degrading enzyme (adamts13) for von willebrand multimers
-causes a thrombosis mesh which tear up RBCs and leads to RBC breakdown
-also infection, drugs, malignancy...
What is pathogenesis of TTP?
-inability to break down Von Willebrand factor causes a thrombosis mesh which tear up RBCs and leads to RBC breakdown
How do you diagnose TTP?
-purely clinical at this time
-ADAMST13 assays are available but are too slow and not universally available
What is therapy for TTP and what should be avoided?
-plasmapheresis
-avoid platelet transfusion
When do you see HUS in children and how old are they typically?
-often follows an episode of bloody diarrhea - shiga toxin
-typically seen under age 5
What is clinical presentation for HUS in children?
-sudden pallor
-black urine then oliguria (low urine output) then anuria
How do you diagnose hemolytic uremia syndrome?
-clinical picture
-stool cultures may be useful
How do you treat hemolytic uremia syndrome?
-supportive
-dialysis
-plasmapheresis doesn't do much
What is HELLP syndrome?
subset of pre-eclamptic or eclamptic patients
-hemolytic anemia
-elevated Liver function tests
-Low platelet counts
What are some symptoms of HELLP syndrome?
-malaise
-right upper quadrant pain
-HTN
-proteinuria
What do you see in the lab for HELLP patients?
-elevations of ALT and AST
-thrombocytopenia under 100,000
-normal coagulation tests, normal assays of fibrinogen turnover
What are some complications with HELLP syndrome?
-abruptio placenta
-DIC
-Post partum hemorrhage
How do you treat HELLP syndrome?
delivery if possible
-otherwise HTN control, Eclampsia control
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