BLI 7 - Macrocytic Anemia (Siddiqui) Flashcards
Salivary gland secretion
R-binder
Increased serum methylmalonic acid
Megaloblastic - B12 deficiency only!
Microcytic sideroblastic anemia
Alcohol can also produce this
alcohol liver disease hypothyroidism MDS reticulocytosis
non-megaloblastic
Jejunum
folic acid absorption
Cofactor for conversion of homocysteine to methionine
Vit B12
Inhibits dihydrofolate reductase
MTX
Terminal ileum
B12 absorption
Years to develop
B12 deficiency
Alcoholics Pregnancy Hemolysis
Folate deficiency
Autoimmune destruction of gastric parietal cells
Pernicious anemia –> no intrinsic factor
Dissociates cobalamin (B12) from R-binder
Pancreatic enzymes
Gastric parietal cell secretions
R-binder Intrinsic Factor
Leafy green vegetables
Folic acid
N10 Formyl THF
Purine synthesis
Months to develop
Folate deficiency
Impaired DNA synthesis
Megaloblastic anemia
Gastrectomy Ileal resection Pancreatic insufficiency Crohn disease Diphyllobothrium latum Vegans (Not vegetarians)
B12 deficiency
Animal derived foods
B12
Cytoplasmic dyssynchrony - maturation of nucleus of bone marrow precursor cells is delayed relative to maturation in cytoplasm
megaloblastic
hypersegmented neutrophils
megaloblastic
Round macrocytes
Non-megaloblastic
Enzyme to convert folic acid to THF
Dihydrofolate reductase
Absent neutrophil hypersegmentation
Non-megaloblastic
Increased serum homocysteine
Megaloblastic - B12 or Folate deficiency
The Cbl-____ complex is taken up by endocytosis, the Cbl is liberated, and converted to two coenzyme forms (___-Cbl, adenosyl-Cbl)
TCII methyl
N5 methyl THF
Methionine synthesis
Pernicious anemia
B12 deficiency
Most common cause of macrocytosis
Alcoholism
MCV 100-110
Non-megaloblastic anemia
Cofactor for methylmalonyl CoA to Succinyl CoA
Vit B12
Negative lab important for dx of folate deficiency
NL methylmalonic acid level
Parasthesias Weakness Visual impairment
Megaloblastic
Drugs associated with megaloblastic anemia
MTX Sulfa Trimethoprim Phenytoin
Increased lab values (2) in B12 deficiency
Homocysteine Methylmalonic Acid
MCV > 110
megaloblastic anemia
______ folate is more reliable, as it remains stable over time
RBC (more reliable than serum)
N5,N10 methylene THF
Thymidine synthesis