Pathoma: Microcytic Anemias Flashcards
Microcytic anemia is always due to __________.
a decreased production of hemoglobin
Why do RBCs divide an extra time in microcytic anemias?
They try to maintain a certain concentration of hemoglobin, and if there is decreased production of hemoglobin, then the cells will divide an extra time (decreasing the cell volume and hence increasing MCHC)
List the four microcytic anemias?
Iron deficiency, sideroblastic (decreased protoporphyrin), chronic disease, and thalassemia
Iron is absorbed in the ________.
duodenum
Iron in the blood is bound to _________.
transferrin
Iron also gets bound to __________ inside the bone marrow (where erythrocytes develop).
protoporphyrin within macrophages
________ is the most common cause of iron deficiency in adult males.
Peptic ulcer disease
__________ is the measure of iron stored in the body.
Ferritin
________ is the measure of transferrin binding.
TIBC
Normal transferrin saturation is __________.
~33%
Early stage iron deficiency leads to _______.
normocytic anemia (same goes for chronic disease)
Pitted nails are called __________.
koilonychia
What is FEP, and how does it relate to iron-deficiency anemia?
Free erythrocyte protoporphyrin (that is, protoporphyrin that does not have iron) and it will be high in iron-deficiency anemia because people don’t have problems making protoporphyrin
How does chronic disease cause microcytic anemia?
Bacteria need iron to grow, so the body’s inflammatory response includes secreting hepcidin, which sequesters iron in storage sites and thereby limits bacterial growth. Further, inflammatory markers decrease the release of EPO.
Why is ferritin high and TIBC low in anemia of chronic disease?
The iron is trapped in storage sites, so the serum iron will be low and the iron saturation will be low, but the ferritin levels will be high.
The binding of iron to protoporphyrin (by ________) occurs in the ________.
ferrochelatase; mitochondria
In sideroblastic anemia, iron gets _________.
trapped in mitochondria because of deficient protoporphyrin
Sideroblastic anemia can be ___________.
congenital (defect in ALAS) or acquired (alcoholism, lead poisoning, and vitamin B6 deficiency)
Lab values reveal _________ in sideroblastic anemia.
iron overload (increased ferritin, decreased TIBC, high serum iron, and percent saturation)
Thalassemia carriers are protected from _________.
Plasmodium falciparum malaria
Alpha globin is located on the _________ chromosome.
16th
It is thought that the cis-deletions of alpha globin are responsible for ____________.
the higher rate of spontaneous abortions among Asians
HgH is _______.
beta tetramers
Barts hemoglobin is _________.
gamma tetramers (seen in hydrops fetalis)
Target cells are present in ___________.
beta thalassemia minor
