Macrocytic Aneamia Flashcards
What defines anemia?
A decrease in hemoglobin concentration below the lower normal limit for age sex
How is anemia classified?
By etiology
severity
What are the main types of anemia based on morphology?
Microcytic normocytic macrocytic
What is macrocytic anemia?
Anemia with an MCV > 100 fL where red cells are larger than normal.
What are the two main types of macrocytic anemia?
Megaloblastic and non-megaloblastic.
What characterizes megaloblastic anemia?
Oval macrocytes with nuclear-cytoplasmic asynchrony in bone marrow erythroblasts often due to defective DNA synthesis.
What is the most common cause of megaloblastic anemia?
Deficiency of vitamin B12 and/or folate.
What characterizes non-megaloblastic macrocytic anemia?
Round macrocytes without nuclear-cytoplasmic asynchrony often due to increased lipid deposition in red cell membranes.
What is the most frequent cause of non-megaloblastic macrocytosis?
Alcohol consumption.
List other causes of non-megaloblastic macrocytic anemia.
Reticulocytosis liver disease
What are the primary causes of vitamin B12 deficiency?
Decreased intake and impaired absorption.
List causes of impaired absorption of vitamin B12.
Pernicious anemia gastrectomy
What are the primary causes of folate deficiency?
Increased demand decreased intake
List conditions with increased demand for folate.
lactation Pregnancy
List dietary causes of folate deficiency.
Old age low socioeconomic status
List absorption-related causes of folate deficiency.
Drugs (e.g. anticonvulsants
How does folate deficiency cause megaloblastic anemia?
It inhibits thymidylate synthesis necessary for DNA synthesis
What is the role of vitamin B12 in folate metabolism?
It converts methyl-THF to THF a necessary substrate for DNA synthesis.
What are common clinical features of macrocytic anemia?
Shortness of breath easy fatiguability
List additional symptoms specific to megaloblastic anemia.
Red beefy tongue angular cheilosis
What initial investigations are done for macrocytic anemia?
Full blood count reticulocyte count
What are additional tests for diagnosing megaloblastic anemia?
Serum vitamin B12 serum and red cell folate
What is the main treatment for megaloblastic anemia?
Supplementation with the appropriate vitamin (IM B12 for severe cases oral B12 for mild cases
What caution must be taken when giving folic acid for megaloblastic anemia?
Ensure no underlying vitamin B12 deficiency before administering folic acid.
What is the typical response to treatment in megaloblastic anemia?
Improvement within 24-48 hours with reticulocyte rise by Day 4
What are the common causes of megaloblastic anemia?
Deficiency of vitamin B12 and folate.
What is the difference between megaloblastic and non-megaloblastic macrocytic anemia?
Megaloblastic anemia shows nuclear-cytoplasmic asynchrony and is commonly due to B12/folate deficiency while non-megaloblastic is often due to alcohol and lacks nuclear-cytoplasmic asynchrony.
