Pathoma 4. RBC Disorders Flashcards
What’s the basic equation of Hb, and how do you see all the Microcytic anemias thru it?
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
Iron deficiency Anemia
n
Where is Iron ABSORBED?
Duodenum
What is ferroportin
it’s the transporter that takes iron from the iEnterocytes, and transfers it to the BV
What’s Transferrin?
TRansfers iron from BV to BM Macrophages or Liver.
WHat’s Ferritin?
It binds Fe in Hepatocytes to store it. Prevents Fe from generatin FR thru Fenton rx
What are the 4 LAB studies for Iron
Serum Iron
TIBC
%saturation
Ferritin
TIBC measures:
TOTAL IRON BINDING CAPACITY
transferrin molecules in blood-bound or NOT BOUND.
what does %SAT?
how many tsfin are actually bound to Iron
Ferritin
Iron bound in BM or Liver
Can children acquire Iron deficiency while they breastfeed?
YES
Hookworms that cause iron def
necator+ancylostoma
can peptic ulcers result in iron deficiencies?
yes
why does gastrectomy result in iron def?
bc he syn less acid. and acid keeps Fe2+ (which is the one that is TAKEN IN)…
Stages of Iron def
- 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.
What’s Koilonykia? And Pica
Koi= spoon shaped nails
pica=eat anything=drive to get iron
What’s RDW
rBC distribution width.
Increases in Iron def bc the spectrum of the different widths of RBC is greater. = size diff
What’s FEP
free erythrocyte protoporphirin
heme= Fe+ + Proto
(when Fe is low, the proto is free!!!
so…
It’s high in Iron def Anemia
What’s Plummer-Vinson Anemia?
Iron def Microcytic anemia + esophageal web (mucosal protrusion) + atrophic glossitis
+ beefy tongue
What’s the most common anemia in hospitalized pct?
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.
ACD first goes thru a ________ phase
normocytic
Ttms for ACD
Treat inflammation (frees hepcidin then Fe) + EPO (specially helps cancer pcts)
Whats sideroblastic Anemia due to
defective protoporphirin syn, which results in low heme and low Hb=anemia
What are the enzymes used in Protoporphirin synthesis?
SCoA uses ALAS(amino-levulinic acid synthase)+B6= ALA- uses ALAD(dehydrogenase to=porphobilinogen that tuns into protoporphirin that + Fe = HEME
What does the final rx of protoporphirin synthesis do and where does it occur?
- Attaches protoporphirin to Fe to make HEME
2. mitochondria
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
WHERE is the Fe in sideroblastic anemia?
MITOCHONDRIA
What’s the rate limiting step in protoporphirin syn?
ALAS (ex that tsf SCoA to ALA)
What’s the deficiency in CONGENITAL sideroblastic anemia
ALAS
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)
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
What happens in thalassemia?
Decreased synthesis of globin chains is called thalassemia (Sickle cell is has a defective globin chain after it’s produced.)
Thalassemia carriers are protected against what type of malaria?
Plasmodium falciparum
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
sym of 1 gene deleted in a-thalassemia=
asym
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
sym of 3 gene deleted in a-thalassemia=
Severe anemia.
Tetramers of Beta chains (B4) = HbH , and damages RBC.
*Seen in electrophoresis
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