RBC 3 Flashcards
define hemolysis
lysis/destruction of erythrocytes, releasing hemoglobin
what are the two types of hemolysis? what is the difference between them?
intravascular: happens when complement is activated due to antibodies on the surface of RBCs causing assembly of a membrane attack complex and lysis of the RBC, causing hgb to leak into the plasma
extravascular: RBCs are phagocytized by immune cells such as macropahges. it can be self antigens OR foreign antigens that “flag” the RBC
if you see ghost cells on a blood smear, what is this indicative of?
intravascular hemolysis (the ghost cell is just the membrane that is left over from RBC lysis)
hemoglobinuria and hemoglobinemia are indicative of what?
intravascular hemolysis: the hgb is IN the plasma causing hemoglobinemia and it will eventually be filtered by the kidney causing hemoglobinuria. this does not happen in extravascular hemolysis because the hgb is not in the plasma, it is within cells
in a more chronic case of intravascular hemolysis, you could see what on bloodwork?
hyperbilirubinemia and bilirubinuria: the body cannot contain how much hemoglobin is being broken down and it is having trouble excreting it, so there is excess bilirubin in the blood and bilirubin present in the urine
what is the most common form of hemolysis?
extravascular is much more common than intravascular
where does extrvascular hemolysis usually happen?
in the spleen, liver, bone marrow, lymphoid tissue, anywhere there are macrophages!
does hyperbilirubinemia and bilirubinuria happen with intravascular hemolysis, extravascular hemolysis, or both?
both, but it takes some time in both cases for this to happen. In a case of extravascular hemolysis it is usually present at presentation, and for intravascular it will develop more with time and may or ay not be present at initial presentation of the patient
if you see this on a peripheral blood smear what should you think of?
extravascular hemolytic anemia, you can see the macrophage has phagocytized a few RBCs and they are in the cytoplasm
if you see these on a blood smear what should you think of?
these are ghost cells, which are indicative of intravascular hemolysis
is hemolysis usually regenerative or non regernative?
regernative unless it is very accute
would you see polychromasia/reticulocytosis on a blood smear if the anemia was caused by hemolysis?
yes, it is usually regernative so you should see polchromatophils/reticulocytes
what is the “clinical” word for the appearance of hyperbilirubinemia? Why does this happen sometimes with hemolysis?
icterus
with hemolysis there is accelerated breakdown of RBCs, and hyperbilirubinemia happens when hemolysis overwhelms the ability of the liver to take up, conjugate, and/or excrete bilirubin
at what level of bilirubin in the blood would you be able to see an icteric patient in front of you?
more than 25-35 micromol/L
there are 7 causes from lecture for hemolytic anemia. list them
- immune mediated (IMHA)
- oxidative damage/exposure to oxidixing agent
- infectious agents
- fragmentation of RBCs (DIC, cardiac valvular disease)
- inherited RBC metabolic defects
- hypophosphatemia
- neoplasia
pneumonic: I only impersonate foxes in harsh Nigeria
IMHA can be primary/idiopathic, or it can be secondary to 5 things which are:
- drugs/toxins
- transfusion reaction
- neonatal isoerythrolysis
- infectious agents
- neoplasia
penumonic: dont try nuggets in Nigeria!
what is the most common hemolytic anemia in dogs?
IMHA
extravascular hemolysis leads to the release of ______ into peripheral blood
spherocytes
what is the theory as to why spherocytes show up on a blood smear/spherocyte formation?
there is partial phagocytosis by macropahges, a peice of the RBC membrane is removed, there is less surface area with the same volume in the cell, leading toa spherical shape, loss of central pallor (like a donut)
what types of cells are these? what do they indicate?
spherocytes, indicative of extravascular hemolysis
what is the classic clinical presentation of IMHA?
- they have a regernative anemia on CBC
- you can see spherocytes on the blood smear
- they are coombs test +
- there is hyperbilirubinemia/bilirubinuria
- inflammatory leukogram (from necrosis, lack of oxygen)
- may have agglutination of RBCs on smear, maybe some ghost cells, and maybe some thrombocytpenia depending
what is a coomb’s test? when is this test useful?
used to diagnose IMHA, it looks for antibodies on RBC surfaces and confirms agglutination
this test is only useful if auto-agglutination is not already present, meaning you didn’t see it on the blood smear
hemolytic anemia of oxidative damage causes what kind of cells to show up on a blood smear?
heinz bodies
what cells are these, what are they indicative of, and what is the logic behind them lookin like that?????
they are heinz bodies in RBCs, and they are indicative of hemolytic anemia of oxidative damage. oxidative damage to hemoglobin causes percipitation of denatured globin of the denatured portion of hemoglobin and this forms heinz bodies in the cells
what are these cells called, and what are they indicative of?
these are eccentrocytes, indicative of hemolytic anemia of oxidative damage, specifically lipid peroxidation of the RBC membrane
list some examples of oxidizing agents for each species
dogs: onion, garlic, acetominophen, zinc, skunk spray
cats: onions, acteominophen
horses: wilted red maples leaves, onions
cattle: brassica species, onions
sheep: copper toxicity
list some infectious agents for each species that can cause hemolytic anemia
mycoplasma sp in cats, dogs, pigs, cattle, llamas
amaplasma marginale in cattle
babesia in cattle, horses, and dogs
others: leptospira, clostridum, equine infectious anemia virus
RBCs are removed because there are infectious agents inside of them
what type of cells would you see on a smear if there was a hemolytic anemia due to RBC fragmentation/mechanical injury?
schizocytes, keratocytes, acanthocytes
with an infectious hemolytic anemia, which is the main underlying mechanism, extravascular or intravascular?
mostly extravascular with maybe some intravascular, often times multifocal
hemolytic anemia due to RBC fragmentation/mechanical injury happens primarily through what mechanism, extra or intravascular?
extravascular hemolysis (the cells appear abnormal and are taken up by macrophages)
after you have diagnosed something with IMHA, are you done?
no! you need to go looking for an underlying cause. primary IMHA (idiopathoc) is a diagnosis of exclusion
