Hematology #3 (Macrocytic Anemias, Hem A & B) Flashcards
What are sources of B12?
Explain the absorption of B12 in the body.
Natural sources (animal in origin): meats, eggs, dairy
B12 released by acidity in stomach and combines with intrinsic factor where it is absorbed in distal ileum
B12 deficiency causes abnormal synthesis of ________
DNA
There are two etiologies of B12 deficiency, decreased absorption and decreased intake. What is the MCC of decreased absorption?
Who should you be concerned with decreased intake in?
Pernicious anemia: lack of intrinsic factor due to parietal cell antibodies, leading to gastric atrophy
Vegans
What are other causes of decreased absorption in B12 deficiency?
Crohn Disease
Chronic alcohol use
H2 blockers and PPIs
Metformin
Celiac Disease
Symptoms of B12 deficiency
-Fatigue, exercise intolerance, pallor
-Glossitis, diarrhea, malabsorption
-Neuro symptoms***: symmetric paresthesias, lateral and posterior spinal cord degeneration (ataxia, vibratory, sensory, and proprioception deficits), decreased DTRs
What is seen on a CBC with peripheral smear for B12 deficiency?
Macrocytic anemia (>100) + megaloblastic anemia (hyperhsegmented neutrophils, macor-ovalocytes)
What other labs are shown for B12 deficiency?
-Decreased serum B12 levels
-Increased homocysteine (B12 breaks this down normally)
What lab distinguishes B12 from folate deficiency?
Increased methylmalonic acid
-B12 converts methylmalonic acid to another enzyme normally.
Treatment for B12 deficiency
-If neuro findings, B12 IM, then oral once symptoms resolve
In patients with pernicious anemia, how often do they get IM B12 injections?
Lifelong, monthly injections as treatment
What test can be done to determine the cause of pernicious anemia?
Schilling’s Test: Inject with B12 to determine the cause
Folate deficiency, another macrocytic anemia, causes ____________
Abnormal synthesis of DNA
Etiologies of folate deficiency
What is the MCC?
-MCC: Inadequate intake (alcoholics, unbalanced diet)
-Increased requirements: pregnancy, infancy, psoriasis
-Impaired absorption: Celiac, IBD, anticonvulsants, diarrhea
-Impaired metabolism: Methotrexate, Trimethoprim
-Loss: Dialysis
Symptoms of folate deficiency
-Like B12, but no neuro symptoms
What is seen on CBC with peripheral smear for folate deficiency?
macrocytic anemia + megaloblastic anemia (hyperhsegmented neutrophils, macro-ovalocytes)
What other labs are shown for folate deficiency and what distinguishes it from B12 deficiency?
-Decreased serum folate levels
-Increased homocysteine
-Normal methylmalonic acid (this is what is different)
Treatment for folate deficiency
-Folic acid supplementation
What are some causes of macrocytic anemia?
-B12 Deficiency
-Folate Deficiency
-Chronic alcoholism
-Chronic Liver disease
-Hypothyroidism
-Acute Leukemia
What does hemophilia mean?
Blood doesn’t clot the way it is supposed to due to lack of proteins/factors
Hemophilia A, which is ________ deficiency, is a X-linked recessive disorder than occurs almost exclusively in males. This is the MC type of hemophilia. What are some symptoms of this?
Factor 8 (VIII) Deficiency –> failure of hematoma formation
-Hemarthrosis: Delayed bleeding or swelling in weight bearing joints
-Excessive hemorrhage due to trauma and surgery or incisional bleeding
-Epistaxis
-Bruising
Regarding clotting factors, PTT (Partial Thomboplastin Time) measures ______ factors whereas PT (Prothrombin Time) measures ______ factors.
Intrinsic
Extrinsic
PTT (aPTT), also known as the time___________, it prolonged in what kinds of conditions?
How long it takes to make a clot
Prolonged: Hemophilia A, B, Heparin, DIC, vWD
What CBC and coagulation studies are present in Hemophilia A?
-Prolonged PTT
-Normal PT
-Normal Platelet Levels (bleeding time)
What is unique about PTT in Hemophilia A and how to fix it?
It corrects with mixing studies
Low Factor VIII is the most sensitive test
Treatment for Factor VIII deficiency
-Factor VIII infusion: can be used in response to acute bleeding or prophylaxis (pre-op, trauma, etc)
-Desmopressin (DDAVP): increases Factor VIII and vWF release from endothelial stores
On the other hand, Hemophilia B is deficiency in what factor? It also occurs almost exclusively in males and has the same symptoms of Hemophilia A
Factor IX (9) Deficiency
What CBC and coagulation studies are present in Hemophilia B?
Prolonged PTT
Normal PT and platelets (bleeding time)
PTT corrects with mixing studies
Factor IX is the most sensitive test
Treatment for Hemophilia B
-Factor IX infusion
What is NOT useful in Hemophilia B that is useful in Hemophilia A?
Desmopressin (DDAVP)
