Anemia I Flashcards
what vitamins are required for RBC production?
iron, folate, vit B12
what conditions will lead to decreased hgb affinity for oxygen?
decreased pH
increased DPG
increased temp
(think exercising!)
MCH
mean corpuscular hemoglobin - measure of mass of hemoglobin per RBC. low = hypochromic
MCHC
conc of hemoglobin in a given volume of packed RBCs
diseases w/ low MCHC
iron deficiency
thalessemia
diseases w/ high MCHC
hereditary spherocytosis, hemolytic anemias
MCV
volume of the average RBC
RDW
measure of degree of variation in RBC size
aniscytosis
high RDW
polychromasia
indicates shift of marrow reticulocytes into the periphery
normal reticulocyte count
0.5% to 2.0% of total RBCS
absolute usually 25K to 75K
reticulocyte production index (RPI)
RPI = reticulocyte % x (Hct/normal Hct) / maturation factor
> 2 = adequate response; <2 inadequate response
if you have anemia and another cell line down, what should you do?
bone marrow biopsy!
with acute blood loss, what will happen to Hgb/Hct?
they may lag (normal at first despite lots of blood loss) - will decrease later as compensatory fluid moves from extravascular to intravascular space
causes of microcytic anemia (5)
- iron deficiency anemia
- lack of iron release from macrophages
- failure of heme synthesis
- failure of globin synthesis
- lead intoxication (inhibits heme and globin synthesis)
hepcidin
peptide that regulates absorption of iron at the duodenum
transferrin and ferritin
transferritin: transporter for circulating iron
ferritin: intracellular storage protein for iron - can be elevated by inflammation
plummer-vinson syndrome
dysphageia
esophageal web
atrophic glossitis
due to IDA
koilonychia
spoon nails assoc w/ IDA
iron deficiency in a patient over 50 raise red flags for ______
colon cancer (until proven otherwise)
tx of iron deficiency
ferrous sulfate (oral or IV) address cause
normal hemoglobin composition in adults
Hgb A1: alpha2-beta2 - 95-98%
Hgb A2: alpha2-delta2 - 2-3%
HgbF: alpha2gamma2 - 0.8-2.0%
beta-thalessemia Hgb levels
beta–thal trait (B/B0): increased Hgb F (1-5%) and increased Hgb A2 (4-7%)
beta-thad major (B0/B0): very increased Hgb F (95+%), Hgb A2 (0-5%)
beta-thal blood smear findings
target cells
microcytosis, hypochromia
geographic distribution of beta-thal and alpha-thalal
beta: mediterranean and SE Asia
alpha: SE asia, africa, india
alpha thalessemia
gene deletion causes impaired production of alpha globin
- 1-2 genes = alpha trait –> low MCV, but no tx req
- 3 genes = beta chains form Hemoglobin H tetramers which are toxic to RBCs. Pts have anemia w/ hemolysis, sometimes need splenectomy.
- 4 genes = formation of gamma aggregates –> hydrops fetalis
sideroblastic anemia
anemia due to a problem with protoporphyrin synthesis –> microcytic anemia
- erythroblasts accumulate iron in the mitochondria but can’t produce adequate heme
sideroblastic anemia blood smear
ringed sideroblasts
basophilic stippling
congenital causes of sideroblastic anemia
ALAS mutation (rate-limiting step in porphyrin synthesis) other steps less common
acquired causes of sideroblastic anemia
primary: myelodysplasia w/ ringed sideroblasts
secondary:
- nutritional (B6 or copper deficiency)
- drugs: isoniazid, other alkalating agents
- alcoholism
- toxins: lead poisoning, zinc
labs in sideroblastic anemia
iron high
high ferritin
normal TIBC
high transferrin
lead poisoning
inhibits heme and globin synthesis
interferes w/ RNA breakdown –> basophilic stippling (sideroblast)
labs: increased Fe, ringed sideroblasts in marrow,
dx: lead level in blood or urine
lead poisoning sx
abdominal pain
neurologial symptoms: neuropathy, headaches, disorientation, insomnia
irritability, psychosis
anemia of chronic disease/inflammation
iron trapped in macrophages –> microcytic anemia
