Hypoproliferative Anemias Flashcards
What retic index or absolute retic count indicates hypoproliferative anemia?
Retic index < 2% or ARC <75,000
Group of disorders characterized by a defect in DNA synthesis whose cells have a immature nuclei but a mature cytoplasm
megaloblastic anemias
B12 and folate deficiency are the most common causes of which kind of anemia?
Megaloblastic anemia
A patient comes in with Anemia,
MCV is elevated, as is RDW
Peripheral smear shows hypersegmented PMNs. What is your differential?
Megaloblastic Anemia
What non hematologic features are only seen with B 12 deficiency and not with Folate deficiency?
Neuro/psychiatric features
Humans are fully dependent on B12 in diet that are found only in
animal products
B12 binds to what protein in the mouth?
salivary R protein
Parietal cells secrete what molecule to aid in B12 absorption ?
intrinsic factor
What proteins free B12 as it travels from the stomach to the small intestine?
pancreatic enzymes
Intrinsic factor binds free B12 and the B12-IF complex taken up by cells in which part of the small intestine?
distal ileum
B12 is carried by what protein/enzyme in the blood to the tissues?
Transcobalamin II
also known as vitamin B12 deficiency anemia, is a disease caused by destruction of gastric parietal cells (therefore no intrinsic factor)?
Perncious anemia
What are the main causes of B12 deficiency?
- Inadequate consumption (vegan diet)
- Inadequate absorption (pernicious anemia, gastric bypass, drugs)
- Reduced B12 absorption in the ileum (Chron’s disease, sprue (celiac), metformin)
- Competition for B12 (fish tapeworm, bacterial overgrowth)
What are some neurologic changes/signs of B12 deficiency?
loss of vibration and position sense in toes due to neurologic changes
Macrocytosis, hypersegmented PMNs, pancytopenia, elevated bili and markedly elevated LDH are lab findings of
B12 deficiency
What is pancytopenia
low counts of all three blood cell types: platelets, WBC, RBC
What other laboratory testings can be done to confirm B12 deficiency?
Homocysteine and methylmalonic acid
What are the differences in the absorption of B12 and folate?
Folate is absorbed throughout the small intestine without any specific transport protein
B12 is absorbed at the distal end of the ileum and depends on multiple enzymes such as:salivary R, intrinsic factor from parietal cells, and pancreatic enzymes
What is our main source of folate?
its mainly found in uncooked green leafy vegetables but the government has fortified all of our food with it
How does one become folate deficient?
- malnutrition (most common cause)
- biliary (tube in the bile) drainage causes profound folate deficiency that occurs within hours because folate is concentrated in bile
- People who need to make lots of DNA can also become folate deficient like pregnant women, people with hemolytic anemias, and anything that can activate cell turnover like psoriasis.
- drugs can also interfere with metabolism
Absolute neutrophil count (ANC) <500/uL
Platelet count <50,000
Absolute reticulocyte count <50,000
Whats on your differential for a patient with this workup?
Pancytopenia caused by a severe aplastic anemia
What does bone marrow biopsy of pancytopenia due to aplastic anemia show?
hypocellularity due to lack of hematopoietic stem cells
True or False: Aplastic Anemia is an autoimmune condition
True
Ionizing radiation, cytotoxic chemotherapy, benzene exposure, EBV, hepatitis, PNH are secondary causes of
Aplastic Anemia
