Lecture 15 Chapter 20 Flashcards
What organ is most affected by extravascular hemolysis
Spleen
What condition affects your platelet aggregation and clot formation inside your vessels
Microangiopathic hemolytic anemia
Cell travels down vessel at high speed and crashes into platelet/clot formation destroying the cell
Can be intrinsic and extrinsic
Describe acute vs. Chronic
Acute = the progress of the symptoms are going to happen very quickly. (ie. symptoms accelerate within 3 months)
Chronic = symptoms extend beyond 3 months
Describe intrinsic vs. Extrinsic
Intrinsic = the problem that results in the destruction of RBCs is within the RBCs
Extrinsic = the causes are outside of the RBCs
Describe inherited vs. Acquired
Inherited = you are born with the condition that results in the destruction of RBCs
Acquired = you were not born with it (mutations/problems occurred after birth)
Describe intravascular vs. Extravascular hemolysis
Extravascular = the RBCs are destroyed outside of the blood vessels, such as in the bone marrow, liver, and spleen
Intravascular = the damage to the cells is done within the blood vessels
Can often have both but look at which is predominant
Normally intravascular = 10% and extravascular = 90%
Diseases that cause excessive extravascular hemolysis
Hemoglobinopathies
Thalassemias
If you receive a fecal specimen in the lab, and the fecal color/material is more gray like chalk, what can cause that?
Color comes from stercobilin
Could be a problem where bile that contains bilirubin cannot empty bile in intestinal tract, which could be a gallstone trapped in the biliary ducts
Worst cases: pancreatic cancer or biliary cancer cause tumor to grow blocking the pathway → bile doesn’t get into intestinal tract → no bilirubin there → bilirubin cannot break down to urobilinogen → no stercobilin produced → no fecal color
What tests/abnormal results support the cause of excessive extravascular hemolysis
Increased retic count cause problem is not in bone marrow
Unconjugated bilirubin goes up
Urobilinogen in urine increased - it you have increased destruction of RBCs in the spleen, you will increase the production of unconjugated bilirubin → goes to liver → albumin is removed and bilirubin get conjugated → gets put in bile that empties into intestinal tract → get broken down into urobilinogen → more bilirubin = more urobilinogen
What happens when a RBC is destroyed intravascularly
The hemoglobin breaks into molecules and the tetromeres become alpha/beta dimers. Haptoglobin binds to dimers and carries dimers to liver → gives them to hepatocytes → breaks it down into bilirubin → recycles everything else → puts bilirubin in bile
What does haptoglobin prevent
The hemoglobin dimers to be filtered through the kidney because if they get filtered through the kidney, your venal tubular cells and proximal convulated tubules will absorb it. The dinners have iron in them so it will increase iron in storage which causes oxidative stressed renal tubular cells → kills venal tubular cells → problems with kidney
What happens when hemoglobin is released into the environment outside of the RBCs
It becomes oxidized → becomes methemoglobin → albumin binds to methemoglobin → hemopexin can take the albumin/methemoglobin complex to liver → liver breaks it down
What can bind to free hemoglobin and take it to the liver
Haptoglobin (binds to a/b dimers)
Albumin
Hemopexin
What happens to your haptoglobin when you have excessive intravascular hemolysis
There will be a rapid drop in haptoglobin because it will grab hgb and take it to liver but will be taken inside liver as well.
Liver can only produce a set amount of haptoglobin so cannot increase amount even when there is an increase in free hemoglobin
What happens when too many cells are destroyed an liver cannot control it?
The hemoglobin will spill over to other organs such as the kidneys, causing kidney failure
What does it tell you when haptoglobin decreases
There is excessive intravascular hemolysis
How does hemoglobinemia relate to intravascular hemolysis and how can you determine if it is present
Intravascular hemolysis increases = hemoglobinemia increases
It look like a red serum in blood sample
What happens when you have hemoglobinaria
Excessive hgb can get filtered through glomerulus and reach proximal tubules. Tubules will try to take as much as it can but once limit is reached, the excess will enter the urine
What is hemosidrin
Oxidized form of ferritin/iron storage
What is hemosidrinuria
Hemosidrin holds iron → if it exceeds amount it will be added to urine → seen on smear as extra iron in cells
What is methemalbuminemia
Hgb is released into blood and is oxidized → Methemoglobin/albumin goes up → if it gets filtered in kidneys color of urine will be like coffee
What are some symptoms of intravascular/extravascular hemolysis
Fatigue, dizziness, dyspnea, pallor, tachycardia
Splenomegaly, gallstones, malaise, aches, vomiting, fever, oliguria, anuria
Color of urine: urobilinogen (stercobilin and urobilin), hemoglobinaria, methemoglobinuria
Why does intra/extravascular hemolysis cause gallstones
They are generating high bilirubin because of the excessive blood loss, so bilirubin will concentrate the bile
What is the retic count, hematocrit, RBC count, and blood smear features of accelerated RBC destruction
Retic count = increased (bone marrow trying to appease body needs)
Hematocrit = decrease
RBC count = decrease
Blood smear features: intravascular = schistocytes, can have thrombocytopenia
What is the result of lactate dehydrogenase (LDH) for intravascular hemolysis
It will increase significantly
If you want to pinpoint what is causing the increase in LDH use electrophoresis to separate the isoforms
How can you differentiate what disease is causing increased LDH
By its isoforms
What is the result of glycosylated Hgb (Hgb A1c) with accelerated destruction
It will decrease because the cells wont be around to be exposed to glucose
What cells will you see in extravascular hemolysis
Spherocytes
nRBCs
Polychromasia
HJ bodies
Where does erythroid hyperplasia come from
Bone marrow will appear hypercellular before hemolytic disease, so the bone marrow will try to increase production of RBCs
