ANEMIA


See also "Iron Deficienty" and Anemia in Children

Definitions:

Patient category Hb HCT
6-24 months   32
2-6y   34
6-12y   35
Boys 12-18yo   37
Nonpregnant girls12-15yo 11.8 35.7
Nonpregnant girls 15-17yo 12.0 35.9
Nonpregnant women > 18yo 12.0 35.7
Pregnant women, 1st trimester 11.0 33.0
Pregnant women, 2nd trimester 10.5 32.0
Pregnant women, 3rd trimester 11.0 33.0

Note that smoking and residency at high altitude will tend to increase Hb and HCT

(Source: MMWR 47 (RR-3):1, 1998--based on 5th %iles from National Health and Nutrition Examination Survey III; data on kids < 12yo from Brent Oldham, M.D.)

I. History:

1. Symptomatic?

2. Recent Blood Loss: melena, hematochezia, menorrhagia, hematemesis

3. Meds

a. NSAID's (GI loss)

b. Alkylating agents, folate antagonists, Dilantin, phenylbutazone (marrow suppression)

c. PCN, sulfonamides, methyldopa (hemolysis)

d. EtOH, INH, trimethoprim (maturation defects)

4. Organ Dysfunction?

a. Severe liver, adrenal, kidney, or thyroid

b. Inflammatory dis?, e.g. SLE, RA, Vasculitides

5. Increased total body H2O (ascites, CHF, pregnancy) can cause pseudoanemia

6. Fam Hx of anemia ?

 

II. Differential Diagnosis:

  1. Pancytopenia : marrow failure, invasion, suppression
  1. Drugs, Ca (solid or heme), inflammatory disease
  1. Low MCV (microcytosis):
  1. Normal RDW
  1. Thalassemia trait
  2. Anemia of "chronic disease" (inflammatory, infectious, neoplastic; see below)
  1. High RDW
  1. Iron deficiency (low serum Fe, high TIBC, low Fe %sat, low serum ferritin)
  2. Sickle-Beta thal
  3. Hb H disease
  4. RBC fragmentation
  1. Normal MCV :
  1. Normal RDW
  1. Normal person
  2. Chronic disease
  3. Chronic liver disease
  4. Recent transfusion
  5. Hb AS, AC, etc.
  1. High RDW
  1. Hemoglobinopathy
  2. Early and/or mixed deficiency, e.g. Fe and folate
  3. Myelofibrosis
  4. Sideroblastic
  1. Low retic count
  1. Nl WBC, platelets = pure RBC aplasia
  1. Congenital
  2. Acquired due to infections, drugs
  1. Nl or low WBC, platelets seen with
  1. Renal disease
  2. Hypersplenism
  3. Chronic disease
  4. Infections
  5. Drugs
  1. Low WBC, platelets
  1. Infiltrative disease (leukemia, etc.)
  2. Aplastic anemia (congenital, e.g. Fanconi's, or acquired, from drugs, toxins, infections, immunologic disease, etc.)
  1. Nl retic count
  1. Enzyme deficiencis
  2. Unstable Hb's
  3. Osteopetrosis (?)
  4. Dyserythropoiesis
  5. Infections
  1. High retic count
  1. Hemorrhage
  2. Hemolysis (click on link for details)
  1. High MCV (macrocytosis)

Note-A "megaloblast" is an unusually large erythroblast.  Megaloblasts in the peripheral blood can be associated vitamin B12 or folic acid deficiency.  Anemia due to either are collectively called "megaloblastic anemia"

Causes of megaloblastic macrocytic anemia:

Causes of non-megaloblastic macrocyticanemia:

 

 
Medications Associated with Macrocytosis
Megaloblastic Macrocytosis
Folate-related changes
  • Oral contraceptives
  • Triamterene
  • Alcohol
  • Biguanides – cholestyramine, metformin (generic, Glucophage), methotrexate
  • Anticonvulsants – phenytoin (Dilantin), phenobarbital, primidone (generic, Mysoline), valproic acid (generic, Depakote)
  • Antibiotics – sulfamethoxazole, trimethoprim, sulfasalazine
  • Reverse transcriptase inhibitors – stavudine (Zerit), lamivudine (Epivir)
Vitamin B-related changes
  • Gastric acid-blocking agents – histamine 2 blockers, proton pump inhibitors
  • Colchicine
  • Neomycin sulfate
Nonmegaloblastic Macrocytosis
Purine antagonists
  • 6-mercaptopurine
  • Azathioprine
  • Acyclovir (generic, Zovirax)
Pyrimidine antagonists
  • Fluorouracil
  • Zidovudine (Retrovir)
Ribonucleotide reductase inhibitors
  • Cytosine arabinoside
  • Hydroxyurea
Alkylating agents
  • Busulfan
  • Cyclophosphamide
Miscellaneous
  • Methotrexate
  • Adriamycin
  • Daunorubicin
  • Benzene and derivatives
  • Imatinib (Gleevec), sunitinib (Sutent)

 

III. Physical Exam:

  1. Vitals with *orthostatics*
  2. Skin : Telangiectasias, palmar erythema, jaundice
  3. Oropharynx : glossitis (Fe, B12)
  4. Heart : murmurs, gallops
  5. Abdomen :
  1. Splenomegaly (hemolysis, thalassemia, leukemia, lymphoma, portal HTN)
  2. Ascites, hepatomegaly
  1. Rectal
  2. Pelvic, if indicated
  3. Neurologic : position and vibration sense (B12)

IV. Labs

  1. Peripheral Smear
  2. CBC with Retic Count, Platelets
  3. Fe Studies (B12, folate)
  4. Haptoglobin, Urine Hemosiderin
  5. Direct/Indirect Coombs' test
  6. PT/PTT
  7. Schilling Test, if indicated
  8. "Discriminant index": MCV/RBC
  1. > 13.5 strongly suggests Fe deficiency
  2. < 11.5 strongly suggests thalassemia minor

 

V. Management:

  1. Emerg., xfusion if hemodynamic compromise/angina
  2. Bone marrow bx if ambivalent hx, px, labs and no obvious cause
  3. Fe Deficiency :
  1. Find source of blood loss
  2. FeSO4 325 mg PO TID
  1. Folate def.: usu. dietary (pregnancy, EtOH)
  1. Folate 1mg PO QD
  1. B12 Deficiency :
  1. Schilling test
  2. Vitamin B12 100 micrograms IM QD x 1 wk then 100 micrograms IM 2x/wk x 1 mo then 100 micrograms IM Qmo for life
  1. Hemolytic: do Coombs' test
  1. Coombs' negative--r/o DIC, microangiopathy,thal, SSA, enzymopathy, paroxysmal nocturnal hemoglobinuria
  1. See also: Erythropoietic Growth Factors