Anemia Flashcards
Components of CBC
RBC, Hgb, Hct, MCV, MCH, MCHC, RDW, WBC, Diff, PLT count, MPV
Total RBCs: normal values
male 4.5-6.0 x 10^12/L
female 3.8-5.2 x 10^12/L
Hgb: values
Normal ranges: male 13-18 g/dL; female 12-16 g/dL
• Hgb below normal = anemia
Hct: values
male 40-52%
female 35-47%
MCV
- Avg volume (size) of RBC
- Normal range: 80-100 fL
- Differentiates between microcytic (MCV < 80), normocytic (MCV 80-100)
- and macrocytic (MCV > 100) anemias
MCH
Weight of Hgb in the average red blood cell
- Normal range: 26-34 pg
- Not a frequently used parameter
MCHC
- Concentration of hb (color)
- Normal range: 32-36 g/dL
- Differentiates between hypochromic (MCHC < 32) and normochromic (MCHC 32-36) anemias
- There is no such thing as a hyperchromic red cell (you can’t put excess hemoglobin into a cell, or it would burst!)
RDW
- Range of variation in RBC volume
- Tells you how much the red blood cells differ from each other in size. If they
- are all pretty similar in size, the RDW is low. If some cells are little and some are big, the RDW is high.
- Normal range = 12-13.5%
Anisocytosis
Elevated RDW
Poikilocytosis
Abnormal blood cell shape that makes up >10% of population
Typically d/t nutrient or B12 deficiencies
TIBC
Blood’s capacity to bind iron to transferrin
increased in IDA
WBC
- Normal ranges: adult: 4.5-11 x 109/L, newborn: 9-30, child over 1: 5.0-17.0
- A high WBC is seen in many conditions. Some are benign, such as infection and inflammation. Others are malignant, such as leukemia.
PLTs
- Normal range = 150-450 x 109/L
- Causes of a low platelet count are numerous and include splenomegaly, idiopathic thrombocytopenic purpura, disseminated intravascular coagulation, and bone marrow failure.
- Causes of a high platelet count are also numerous, and include reactive thrombocytosis (as seen in iron-deficiency anemia) and essential thrombocythemia.
MPV
- Mean plt volume
- Average size of platelets
- Normal range depends on the platelet count! (Normally, if the platelet count falls, the body compensates a little by trying to make bigger platelets.)
- Not used all that often.
IDA: pathogenesis
Bleed or bad diet/malabsorption
Iron deficiency: order of change in labs
- Low Ferritin, low iron, increased RDW, increased TIBC, changes in H/H, decreased indices (small, pale)
- other changes:
- PLT increased (erythropoiesis can increase PLT counts)
- *serum ferritin is most sensitive!
Anemia of chronic disease labwork
- Typically normochromic, normocytic, minimal anisocytosis and poikilocytosis. Sometimes microcytic, rarely <72 MCV
- Iron studies: Low iron, Low TIBC, normal or increased ferritin
- Low retic count
Treatment for anemia of chronic disease
Usually too mild to treat – focus on underlying cause
Vitamin B12 replacement: when, route
- R/O causative factors before supplementing
- Traditionally: Daily IM injection 1mg cobalamin x 1 wk, 1mg weekly x 4 weeks, 1 mg monthly for life
- Reasonable to begin 1000-2000 mcg PO QD if MMA <400 pg/mL
- Parenteral, nasal, oral: PO is found to be sufficient now d/t passive absorption rate 1% in small bowel – will get more than RDA of 2.4 mcg/day
Most common cause B12 deficiency
Pernicious anemia
Typical sx and PE findings of B12 def
- Typical Symptoms
- weakness, fatigue, lightheadedness, tachycardia, palpitations, angina, sx CHF
- Neuro sx – late, typically BL, LE, leading to late cerebral involvement
- PE findings
- Pale, icteric skin, atrophic glossitis, rarely -purpuric lesions s/t thrombocytopenia
Lab findings in B12 def
- macro-ovalocytic erythrocytes, megaloblasts, hypersegmented neutrophils
- Absolute retic, leukocyte, PLT counts: nl to low
- MMA! Very important as FA supplementation may = no macrocytes. MMA rises when B12 <400.
Who to screen for B12 def
- Any pt w/normocytic anemia! FA supp is screwing us up!
- All elderly pts
- T2D on metformin
- Prolonged PPI
- Excessive physical stress
- c/o imbalance, decreased sensation in LE
- Celiac/Crohn’s
- Oral ulcers
- tongue complaints
- persistent mild diarrhea
- memory loss
- ?persistent irritability
- autoimmune DO
PICA associated with…
IDA – ice
No clear reason
RLS associated with
IDA
Etiology of anemia of chronic disease
immune driven: cytokines and cells of the reticuloendothelial system induce changes in iron homeostasis, the proliferation of erythroid progenitor cells, the production of erythropoietin, and the life span of red cells
Target for Procrit success in patients w/CDK / undergoing hemodialysis
- Hb 11-12
- Hct: 33-36, but not in target range (was found to be associated w/greater mortality)
- Much controversy on the right targets
Iron absorption in anemia of chronic dz
- Iron is absorbed in duodenum.
- Absorption is downregulated in acd – hard to get iron to a place where it can be used.
- If combined w/EPAs, can work well as EPAs able to use it – however, only if low ferritin, as can be harmful if ferritin is nl or high.
Macrocytic anemia: expected lab values
MCV: >100 fL
MCHC: normal
Serum Folic Acid: <4 ng/mL
Serum cobalamin: <150pmol/L
Homocysteine: >13 micromol/L
Serum methylmalonic acid: >0.4 micromol/L
Urine methylmalonic acid: >3.6 micromol/mol creatinine
Describe vit B12 absorption
Gastric acid and pancreatic proteases release dietary vitB12 → Free Vit B12 binds w/intrinsic factor (IF) → Vit B12-IF complex absorbed in ileum
Where is FA absorbed?
proximal jejunum
Why is FA important?
Essential for DNA synthesis – major impact on cells w/rapid turnover
How long does Vit B12 deficiency continue?
Typically lifelong
What is microcytic anemia?
Deficiency in oxygen carrying erythrocytes Microcytic & hypochromic → small erythrocytes w/insufficient Hb (hence pale)
Expected lab values w/microcytic anemia
Mean Cell Volume (MCV): <80fL
Mean Cell Hemoglobin Concentration (MCHC): <30%
Serum Iron (SI): <30 mcg/dL
Transferrin saturation: <10%
Serum ferritin: <20 mcg/
Types of PO iron
Ferrous sulfate (Feosol) Ferrous gluconate (Fergon) Ferrous fumarate (Feostat)
When is iron best absorbed?
on empty stomach but may take w/food to minimize GI effects
How long should iron supplementation continue in IDA?
3-6mths after correcting IDA cause
What are the indications for the different types of IV iron?
INFeD: IDA
Ferrlecit & Venofer: CKD pts on hemodialysis
Special consideration for INFed?
requires test dose prior to 1st admin
