Pathoma 4. RBC Disorders Flashcards
1
Q
What’s the basic equation of Hb, and how do you see all the Microcytic anemias thru it?
A
Hb=heme+globin
heme=Fe+Protoporphirin
4 TYPES:
- Iron deficiency or
- Iron locked in cell (thru Chronic inflammation) can be causes
- Proto deficiency= sideroblastic anemia
- globin deficianty=Thalassemias
2
Q
Iron deficiency Anemia
A
n
3
Q
Where is Iron ABSORBED?
A
Duodenum
4
Q
What is ferroportin
A
it’s the transporter that takes iron from the iEnterocytes, and transfers it to the BV
5
Q
What’s Transferrin?
A
TRansfers iron from BV to BM Macrophages or Liver.
6
Q
WHat’s Ferritin?
A
It binds Fe in Hepatocytes to store it. Prevents Fe from generatin FR thru Fenton rx
7
Q
What are the 4 LAB studies for Iron
A
Serum Iron
TIBC
%saturation
Ferritin
8
Q
TIBC measures:
A
TOTAL IRON BINDING CAPACITY
transferrin molecules in blood-bound or NOT BOUND.
9
Q
what does %SAT?
A
how many tsfin are actually bound to Iron
10
Q
Ferritin
A
Iron bound in BM or Liver
11
Q
Can children acquire Iron deficiency while they breastfeed?
A
YES
12
Q
Hookworms that cause iron def
A
necator+ancylostoma
13
Q
can peptic ulcers result in iron deficiencies?
A
yes
14
Q
why does gastrectomy result in iron def?
A
bc he syn less acid. and acid keeps Fe2+ (which is the one that is TAKEN IN)…
15
Q
Stages of Iron def
A
- Storage iron is depleted= low Ferritin and high TIBC (bc whenever Ferritin is down, transferrin molecules go up to try to find more Fe to bind to!!!)
- Serum Iron is consumed and ALWAYS Saturation goes down.
HY= 3. NORMOCYTIC ANEMIA: Cells are normal in size, but they’re making less cells
- MICROCYTIC= (couldn’t handle it anymore). cells smaller than normal bc they underwent an extra division.
16
Q
What’s Koilonykia? And Pica
A
Koi= spoon shaped nails
pica=eat anything=drive to get iron
17
Q
What’s RDW
A
rBC distribution width.
Increases in Iron def bc the spectrum of the different widths of RBC is greater. = size diff
18
Q
What’s FEP
A
free erythrocyte protoporphirin
heme= Fe+ + Proto
(when Fe is low, the proto is free!!!
so…
It’s high in Iron def Anemia
19
Q
What’s Plummer-Vinson Anemia?
A
Iron def Microcytic anemia + esophageal web (mucosal protrusion) + atrophic glossitis
+ beefy tongue
20
Q
What’s the most common anemia in hospitalized pct?
A
ACD (Anemia of chronic disease)
Hepcidin sequesters Iron into storage. (locks it in Macrophages from erythroid precursors)= this mechanism “hides”iron from supposed bct in the chronic inflam.
Suppresses EPO production.
21
Q
ACD first goes thru a ________ phase
A
normocytic
22
Q
Ttms for ACD
A
Treat inflammation (frees hepcidin then Fe) + EPO (specially helps cancer pcts)
23
Q
Whats sideroblastic Anemia due to
A
defective protoporphirin syn, which results in low heme and low Hb=anemia
24
Q
What are the enzymes used in Protoporphirin synthesis?
A
SCoA uses ALAS(amino-levulinic acid synthase)+B6= ALA- uses ALAD(dehydrogenase to=porphobilinogen that tuns into protoporphirin that + Fe = HEME
25
What does the final rx of protoporphirin synthesis do and where does it occur?
1. Attaches protoporphirin to Fe to make HEME
| 2. mitochondria
26
How does the ring form in sideroblasts in sideroblastic anemia?
Iron always goes into the mitochondria to bind protoporphirin (thru FERROQUELATASE) to make Heme. When there's no Proto, the iron get's stuck in there. And since mtc usually surround the nucleus it'll look like a ring under prussian Blue
27
WHERE is the Fe in sideroblastic anemia?
MITOCHONDRIA
28
What's the rate limiting step in protoporphirin syn?
ALAS (ex that tsf SCoA to ALA)
29
What's the deficiency in CONGENITAL sideroblastic anemia
ALAS
30
What other acquired things Cause Sideroblastic anemia?
```
alcohol
lead poisoning (denatures ALAD + ferroquelatase)
VIT. B6 def (bc ALAS req B6 as co-fct (ISONIAZID causes B6 def)
```
31
Lab findings in SA
THINK= iron OVERLOADED state, in which sideroblast dies and iron flows into blood and BM
So...
High Ferritin low TIBC
High serum iron and %sat
*Same findings for iron status in Hemochromatosis
32
What happens in thalassemia?
Decreased synthesis of globin chains is called thalassemia (Sickle cell is has a defective globin chain after it's produced.)
33
Thalassemia carriers are protected against what type of malaria?
Plasmodium falciparum
34
Whatá Alpha-thalassemia?
Decreased production of alpha globin chains. due to GENE DELETION!!!!
Normally there are 4 alpha alleles on c16. Depending on how many are knocked out=clinical findings
35
sym of 1 gene deleted in a-thalassemia=
asym
36
sym of 2 gene deleted in a-thalassemia=
mild anemia with slightly high RBC count
CIS= 2 were deleted from SAME c16 (WORST!! higher chance of passing on to offspring) more commonly seen in asians.
(related to higher rate of spontaneous abortions in Asia)
TRANS= knocked out from diff c16. one from each
37
sym of 3 gene deleted in a-thalassemia=
Severe anemia.
Tetramers of Beta chains (B4) = HbH , and damages RBC.
*Seen in electrophoresis
38
sym of 4 gene deleted in a-thalassemia=
HYDROPS FETALIS= LETHAL
HbF (fetus) has alpha2gamma2, so if there's no alpha, the gammas get together and for gamma tetramers= called Hb Barts, that damage RBCs. (concept= tetrameres hurt RBCs)
*Seen in electrophoresis
39
What si B-thalassemia?
GENE MUTATION!!! 2 B (B2) genes are on c11. mutation causes B0 or B+...no more B2 :(
40
B-Thalassemia MINOR. what happens?
Bnormal/B+. Mildest form of disease. Asym
Electrophoresis= increased HbA2!!!
41
B-thalassemia MAJOR. it's the opposite extreme. what happens?
Most severe form of disease/ANEMIA!
Takes few months to develop!
(no prob in fetus, bc we don't need Beta chains in fetus)
alpha tetrameres form and damage RBCs= ineffective erythropoiesis, extravascular hemolysis!!!
bc it's so severe the pct gets MASSIVE ERYTHROID HYPERPLASIA= in skull (Crewcut on X-ray) and face bones (thickens= chipmunk face) = indicates massive expansian of hematopoesis
Extramedullary hematopoiesis
42
In b-thalassemia Major What causes the risk for secondary hemochromatosis?
the Chronic transfusions! bring to much iron in!
43
What's the key finding in electrophoresis B-thal MAJOR
NO HbA!
44
What is macrocytic anemia and causes
>100 (inability of cell to divide 1 extra time)
| CAUSES= def in folate/B12
45
Folate comes into the body as
THF. It soon is methylated into M-THF.
46
Lack of folate or B12 lead to impaired DNA synthesis and 2 hallmark traits
1. Megaloblastic RBC
| 2. Hypersegmented neutrophils.
47
Other 3 causes of megaloblastic anemia
Alcoholism, Liver disease, 5-FU
48
where is folate absorbed?
Jejunum
49
how long for folate def to develop?
months
50
Causes for folate deficiency
1. Poor offer/diet (alcoholism, elderly)
2. High demand (pregnancy, cancer, hemolytic anemia)
3. Folate antagonists (Methotrexate- inhibits DHF reductase)
51
Lab findings for Folate def
1. macro+hyperseg N
2. Low folate
3. High homocysteine
3. glossitis
4. Normal Methylmalonic
52
Where is intrinsic factor produced?
Parietal cells of body of stomach
53
where is B12 ab?
Ileum
54
how long to develop def?
years!
55
Most common cause of B12 def
PERNICIOUS ANEMIA. AI destruction of parietal cells, leads to IF def.
56
Other causes of B12 def
1. Pancreatic insufficiency (Pancreas syn ptns that cleaves away R-binder, that allows B12 to be bound to IF.
2. Damage to terminal ileum due to Crohn/Diphylobothrium latum inf (fishtape worm)
3, Dietary Def (vegans) VERY RARE
57
Lab findings of B12 def
```
Macrocytic anemia+hyperseg N
Glossitis
Spinal cord degeneration
Low serum B12
High Homocysteine
High Methylmalonic Acid (B12 is needed in converting Methylmalonic Acid to SCoA.
```
58
How can we diff if Normocytic anemia is dueto overdestruction(spleen) or underproduction (BM)?
Reticulocytes
59
Why r reticulocytes blue?
RNA
60
Reticulocytes can be falsely _______ in anemia
elevated
61
If corrected reticulocyte count is>3% it's a ____problem
spleen
62
If corrected reticulocyte count is <3% it's a ____problem
BM
63
Extravascular hemolysis happens thru
Macrophages of liver, spleen, etc
64
Findings of Extravascular hemolytic anemia
jaundice, Ret>3%, increased Bilirubin gallstones.
65
Findings of Intravascular hemolytic anemia
Destruction is w/i BV.
1. Hemoglobinemia
2. Hemoglobinuria
3. Hemosiderinuria (Hb is also destroyed in kidney and iron piles and binds in tubule cells, which turnover and fall off)
4. Decreased serum haptoglobin (Haptoglobin binds Hb to take it to spleen and save!! and so Hapt is low in serum bc it's being used up for that)
66
Hereditary spherocytosis
Spherocytes loose maneuver. Consumed by splenic macrophages
high RDW
high MCHC (mean corp Hb concentration)!!! only disease where it increases.
Jaundice.
Bilirrubin gallstones.
67
Why does jaundice happen?
Increased hemolysis leads to high circulating unconjugated Billirubin, which overflows liver's ability to conjugate, flowing also into gallbladder
68
What disease is dx by Osmotic fragility test?
HS. (heredit spherocytosis) increased fragility in hypotonic solution
69
Ttm and posterior Lab findings for HS
Splenectomy.
anemia goes away, spherocytes persist
holly jolly bodies (remains of nucleus that were usually removed by spleen)= indicated splenic dysfunction or absence.
70
Sickle cell results from a change of what aa?
glutamic acid to Valine
71
what % of Hb are HbS in Sickle?
90%
72
What gives sickle cells their shape?
polymerisation
73
Under what conditions does polymerisation of sickle cell happen? (driving factors that increase risk of sickling
when they're Deoxygenized: acidosis, dehydration, hypoxemia.
74
What is the most protective factor against sickling?
HbF!!! High levels at birth are protective until 6mo, and using Hydroxyurea increases HbF!
75
Do cells continuously sickle and desickle everytime they pass thru microcirculation?
yes!! and that causes MEMBRANE DAMAGE! leading spleen to filter them out.
76
What type of hemolysis results from sickle cell anemia? And findings:
EXTRAVASCULAR. Anemia, Jaundice w/ UC bilirubin , increased risk for bilirubin gallstones.
also a bit of INTRAVASCULAR: causing low haptoglobin+ + target cells on blood smear (TARGET=bc as mb gets damaged, RBC dehydrate and mb blebs happen in the middle, which fills bleb with Hb=red)
77
what's the main systemic result of INTRA/EXTRAVASCULAR Hemolysis?
massive erythroid hyperplasia=skul + facial bones, then LIVER.
78
What risk does Parvovirus B19 infection bring in anemia?
It invades erythroid precursors and brings risk of Aplastic Crisis.
79
Irreversible sickling leads to
VASO-OCCLUSION
80
What are the complications of vaso-occlusion?
1. Dactylitis= this is the common presenting signs of INFANTS! Classic vignette=child w/ 6mo (swollen hands and feet due to infarcts of bones)
2. Autosplenectomy= leads to high risk of Staph (encapsulated) infections=+fq cause of death in children.
+risk of Salmonella osteomyelitis
Howell-Jolly bodies in blood smear.
3. Acute Chest Syndrome= due to vaso-occlusion. most common cause of death in adults. = pct gets Pneumonia 1st, then syn with Sickling!
4. Renal Papillary Necrosis
81
How does Sickle cell trait work?
ONLY 1 GENE IS AFFECTED. Asym!!!! bc they have <50% HbA, and therefor don't sickle!
82
What is the only exception of Sickle cell trait that develops sym?
Extreme hypoxia/hypertonicity cause sickling=microinfarctions=hematuria=decreased ability to concentrated urine
83
Lab findings in Sickle cell disease:
1. Sickle cells and target cells
2. Metabisulfite screening test shows ANY amount of HbS= so it dx Sickle Trait + disease!!!
3. Electrophoresis
84
What is the main EF finding in SC disease/ vs. Trait?
```
DISEASE= 90% HbS
TRAIT= 55% HbA, 43% HbS
```
85
What is the aa change in HbC anemia?
Glutamic acid changes to LYSINE (lyCCCCine) instead of Valine, as in Sickle.
less common than Sickle
86
Classic finding of HbC aneia?
HbC crystals.
87
What is PNH (paroxysmal nocturnal hemolysis?
ACQUIRED defect in myeloid stem cells that results in absent GP1 (the rcp for DAF/MIRL), making cells susceptible to complement damage when it's turned on at night.
88
PNH results in INTRAVASC hemolysis leading to...
hemoglobinemia
hemoglobinuria
hemosiderinuria
89
What test diagnoses PNH?
SCREENING=Sucrose test! this activates complement and hemolysis will be seen if PNH+
CONFIRMATORY=
Acidified serum test
Flow Cytometry to detect lack of CD55 (DAF)
90
G6PD
low G6PD=low NADPH= can't neutralize H2O2= oxydative stress damage to cells
It precipitates Hb as HEINZ BODIES= Splenic Macriphages eliminate them causing BITE CELLS
Mediterranian variant is worse than African.
Results in Intravascular hemolysis.
Dx: Heinz Preparation study + Enzyme test
91
what is IHA and dx
immune hemolytic anemia. has 2 types: igG mediated or IgM
Dx:
DIRECT Coombs test confirms Ab on RBCs
INDIRECT confirms Ab in serum
92
IgG mediated IHA
binds RBCs in central body (warm agglutinin) SLE, CLL, Drugs (cephalosporin/penicillin)
93
IgM mediated IHA
Binds RBCs in extremities (cold agglutinin)
| Associated with Mycoplasma pneumoniae and infectious mononucleosis.
94
Microangiopathic Hemolytic Anemia
```
SCHISTOCYTES= hallmark bc cells get sheared when pass thru microthrombi.
TTP= def in ADAMS13 /HUS= e.coli )157-HS
DIC= / HELLP
```
95
Malaria fevers = RBC destruction.
falciparum=daily
| vivax/ovale= every other day
