Microcytic Anemia Flashcards
reasons for microcytosis
decreased globin production
decreased heme productio
reduced Fe availabilty
2 reasons for reduced globin producton
thalassemia
hemoglobinopathies
2 reasons for reduced heme synthesis
lead poisioning
sideroblastic anemias
2 reasons for reduced Fe availability
absolute Fe deficiency
functional Fe deficency (chronic illness/inflammation
prevalence of Fe from most to least
hemoglobin
ferritin in MO, spleen, bone marrow, liver
myoglobin
bound to transferrin (in plasma)
iron excretion
no physiologcial way exept 1-2 mg/day lost through desquamation (shedding skin)
hepcidin
how Fe absorption is regulated at level of duodenum
heme
iron complexed to protoporphyn IX
enhances Fe absorption
ascorbic acid
reduced Fe absorption
Ca, antacids, phyates (in brans and oats), polyphenols (in tea and some veggies)
TS
how much of the transferrin is bound to Fe
decrease= decreased Fe
increase= iron overload
best test to show if Fe deficiency is present
ferritin
ferritin can be elevated by
inflammation
causes of Fe deficiency
inadequate oral intake inadequate absorption (messed up duodenum) increased loss (bleeding) intravascular hemolysis depletion of epo
clinical signs Fe deficiency
pica
restless leg syndrome
plummer-vinson syndrome
thalaseemias
autosomal recessive quantitative disorder with insufficient production of alpha and beta-globin chains
normal adults hb types
95-98% HgbA1 (a2b2)
2-3% HgbA2 (a2d2)
1-2% HgbF (a2,g2)
where does B thalasemia occur?
SE asia (burma, thailand, cambodia, vietname, china, malaysia, indonesia, phillipines)
B thalasemia produces no
HbA1- agg of alpha chans therefore decrease in RBC lifespan
compensatory mech of B thala
increase in fetal Hb
alpha thal found in
se asia
africa
india
what happens in a thal
impaired production of alpha globin chans wth resultant excess beta globin chains that are toxc to RBC membrane skeleton
treatment thal a
does not require much; sometmes splenectomy
genetc counseling can be helpful to reduce rsk of H dsease and hydrops fetalis
comp mech of thal a
relative excess of other chains
diagnoss thal a
dna analysis
sideroblastic anemia
decrease in heme synthesis; erythroblasts accumulate Fe in mitochondra without being able to produce adequate heme
primary sideroblastic disease
myelodysplasia with ringed sideroblasts
secondary sideroblastic disease
nutritional: B6 or Cu deficiency
Drugs- isoniazid, chloramphenicol, phenacetin, alkylating agents
alcohol
toxins: lead, zinc poisioning
labs sideroblasts
serum Fe- INC
ferritin- INC
Transferrin (total Fe)- normal/dec
TS- INC
treatment sideroblastic anemia
figure out cause
try pyrdoxine or folic acid
iron chelators/PRBC transfusions`
neurological findings with lead poisioning
motor neuropathy
autonomic neuropathy–> abdominal pain and lead colic
insomnia, irritability, psychosisw
what does lead do to your body
inhibits both heme and globin synthesis, interefers with RNA breakdown which causes accumulaton of denatured RNA in blood cells–> basophlic stippling
treatment lead poisioning
chelators
remove agent
