macrocytic anemias Flashcards
what is a macrocytic anemia
- retic are big
- grouped as megaloblastic vs macrocytic
- > 100 MCV vs > 115 MCV
mechanisms of macrocytic anemia
- abnorm in DNA metabolism (b12 or folate def)
- shift to immature cells
- bone marrow disorders- MDS
- hypothyroidism
- alcoholism
how does alcoholism cause macrocytic anemia
- unknown mechanism
- acetaldehyde has direct effect on RBCs
- d/t regular ingestion of 80 g of alcohol daily
- resolution after 2-4 mo
types of macrocytic anemias
- reticulocytosis
- alcoholism
- liver disease
- hypothyroidism
- med effect
- aplastic anemia
types of megaloblastic anemia
- B12 def
- folic acid def
meds that cause macrocytic anemias
- combo antiretroviral therapy for HIV
- hydroxyurea for sickle cell disease
- mtx- inhibits dihydrofolate reductase
aplastic anemia
- considered a macrocytic anemia
- more common in Asia
- biphasic age distribution: 10-25 vs > 60
causes of aplastic anemia
- acquired causes
- autoimmune
- congenital causes
- fanconi anemia
- dyskeratosis congential
acquired causes of aplastic anemia
- radiation and chemo, toxins
- viral infx
- drugs
- immune disorders
- pregnancy
clinical presentation of aplastic anemia
- weakness, fatigue
- cardiopulm compromise
- progressive anemia
- mucosal/ skin bleeding, petechiae, menorrhea in women
- recurrent infx
what is a common cause of death in aplastic anemia
- invasive fungal infections
PE findings for aplastic anemia
- generally not helpful
- pallor or petechiae common
- purpura
lab study findings in aplastic anemia
- pancytopenia, severe anemia
- normocytic or macrocytic
- decreased or absent polychromic RBCs
- reduced cell components, morphologically normal
- abnormal cells NOT present
- retic count decreased
diagnostic criteria for aplastic anemia
- bone marrow cellularity < 30%
- absence of severe pancytopenia
- depression of 2-3 blood elements below normal
severe aplastic anemia criteria
- bone marrow bx shows < 25%
- OR
- bone marrow bx showing< 50% with the following:
- < 30% of cells are hematopoietic
- absolute retic count < 40,000
- absolute neutrophil count < 500
- platelet count < 20,000
very severe aplastic anemia
- criteria for severe met
- ANC < 200
essentials for dx of aplastic anemia
- pancytopenia
- no abnormal hematopoietic cells in circulation or in bone marrow
- hypocellular bone marrow
treatment for mild-mod aplastic anemia
- supportive care, treat underlying cause
- EPO GF likely wont work
- myeloid GF
- transfusions
- abx or antifungals for infx
- monitor closely
treatment for severe aplastic anemia
- allogenic HSCT tx of choice in kids < 20, preferred in adults 20-50
- immunosuppressive if adults > 50 without HLA match, consider with severe comorbidities
prognosis of aplastic anemia
- if untreated 70% 1 year mortality
- rapidly fatal if severe and untreated
- most die from fungal infections
- good survival if HSCT, immunosupressives, improved supportive care
- 1/3 of pts will relapse
fanconi anemia
- most common cause of congenital inherited aplastic anemia
- autosomal recessive, dx very young d/t severe congenital abnorm
- progressive bone marrow failure
what is a complication of fanconi anemia
- increased malignancy like AML or ALL
treatment for fanconi anemia
- supportive modalities
- androgens
- hematopoietic GF for transient improvement
- many become refractory or dev intolerable side effects
- allogenic HSCT is only option to restore function
when would you consider a B12 or folate deficiency based on H&P
- unexplained neuro si/sx
- older adults
- alcoholics
- patients with malnutrition
- bariatric surgery pts