Topic 4: Microangiopathic Hemolytic Anemia Flashcards
what is microangiopathic hemolytic anemia?
MAHA
a type of anemia in which red blood cells (RBCs) are actually getting physically ripped apart
“microangiopathic” part of MAHA refers to the fact that most of the time, this ripping apart of the RBCs happens within little vessels (but they can get ripped apart in other places too)
all hemolytic anemias have RBC destruction but in MAHA the RBCs are literally getting ripped open
why are RBC in MAHA more likely to get ripped apart in small vessels?
Most of the time, the underlying problem is the formation of fibrin strands, which drape across the vessel lumen and snag RBCs as they pass through
can be caused by obstetrical complications or cancer or sepsis, etc.
what conditions can lead to MAHA?
- DIC
- TTP
- HUS
- HELLP syndrome
- malignant hypertension
- prosthetic heart valve
what is DIC?
disseminated intravascular coagulation
a state in which there is widespread formation of blood clots with simultaneous bleeding due to the consumption of coagulation factors
can cause MAHA
what is TTP?
thrombotic thrombocytopenic purpura
a disease in which there is both fragmentation and the destruction of platelets
can cause MAHA
what is HUS?
hemolytic uremic syndrome
similar to TTP
differentiated from TTP in that HUS is more likely to cause renal damage.
can cause MAHA
what is HELLP syndrome?
HELLP: hemolysis, elevated liver enzymes, low platelets
what is malignant hypertension?
diagnosed when a patient’s blood pressure is so elevated that it can lead to organ damage and the narrowing of the vasculature can cause RBC fragmentation
can cause MAHA
how ca a prosthetic heart valve cause MAHA?
can cause mechanical shearing of RBCs
Prosthetic valves are sometimes made of metal, and what happens to fragile RBCs as they smack against a giant piece of metal?
Exactly what you think would happen: they shatter
what will the CBC of a MAHA patient show?
- low Hb
- normal MCV
if underlying disease causes thrombocytopenia like in DIC and TTP/HUS there will also be a low platelet count
what will the clinical presentation of MAHA be?
patient with MAHA may present with typical signs of anemia (pallor, fatigue, etc.)
but in the end, the clinical presentation depends on the underlying cause
what will a MAHA blood smear show?
- increased reticulocytes
- schistocytes = most characteristic finding!
- triangulocytes
what are schistocytes?
RBC fragments
identifiable by their small size, lack of central pallor, and their pointy edges
found in MAHA blood smear
how do you treat MAHA?
find the underlying cause and treat that cause
blood transfusion or platelet transfusion may not be too helpful in
the long run if we do not treat whatever is causing the narrowing or obstruction of the vasculature
ex. in HELLP, delivering the fetus can eliminate the MAHA
ex. for malignant hypertension, we treat the hypertension
ex. TTP can be treated with plasmapharesis
what size are RBCs in MAHA?
normocytic
MCV would be normal
RBCs are fragmented due to physical stress - there is no defect in RBC synthesis that would lead to micro or macrocytosis
