Anemia- Module 4 Flashcards
What hemoglobin concentration (for adult men & women) suggests anemia?
Men: <12 g/dl
What are reticulocytes? What does the reticulocyte count evaluate?
Immature RBCs; The bone marrow production of RBC’s
What level indicates a high reticulocyte count? What does this indicate?
> 3%; body is compensating for blood loss
What level indicates a low reticulocyte count? What does this indicate?
<1%; RBC production is impaired
What lab value differentiates microcytic, normocytic, and macrocytic anemia?
Mean corpuscular volume (MCV)
What are the three mechanisms that affect blood volume (and therefore anemia)?
- Blood loss
- Decrease in RBC production
- Increase in RBC destruction
What three types of laboratory values are used to discover which mechanism is the cause:
- CBC (hgb, hct)
- RBC indices (MCV, reticulocyte count)
- Iron indices (ferritin, TIBC, serum iron)
90% of anemias fit in what three categories?
- Iron-deficiency
- Thalassemia
- Anemia of chronic disease
Hemoglobin: normal values (women & men)
Women: 12-16 g/dl
Men: 13.5-17.5 g/dl
MCV: normocytic value
80-99 fL
MCV: microcytic value
<80 fL
MCV: macrocytic value
> 100 fL
Serum Iron: Normal value (women & men)
Women: 65-165mg/dl
Men: 75-175 mg/dl
What is serum iron?
Iron bound to transferrin (plasma carrier protein), that regulates iron transport in the blood.
What is serum ferritin?
Reflects total body iron stores.
Serum ferritin: normal values (women & men)
Women: 12-150 mg/L
Men: 15-300 mg/L
What is the first value to reflect depleted iron stores?
Serum ferritin
What does the Total Iron-Binding Capacity (TIBC) reflect?
The availability of binding sites on the protein for iron transport.
How is transferrin level measured?
Indirectly through TIBC.
% calculated by serum iron/TIBC x 100
TIBC: normal level
240-450 mg/dl
% of transferrin saturation: normal values
20%-50%
Early Iron Deficiency lab values:
All normal (earliest to drop is serum ferritin)
Intermediate Iron Deficiency values:
Hgb: N; MCV: N; MCHC: N; Serum Iron: low/N; Serum Ferritin: low; TIBC: High N; Transferrin Sat: low
Late Iron Deficiency values:
all Low; EXCEPT: TIBC is High
Thalassemia minor lab values:
Hgb: Low N/Low; MCV: Low; MCHC: N/Low; Serum Iron: N; Serum Ferritin: N; TIBC: N; Transferrin Sat: N
Chronic Disease lab values:
Hgb: Low N; MCV: N/low; MCHC: N/low; Serum Iron: Low; Serum Ferritin: High; TIBC: Low; Transferrin Sat: High
Sideroblastic Anemia lab values:
Hgb & RBC indices: LOW; Iron indices: all HIGH except TIBC: N
Causes of microcytic anemia
IDA, thalassemia, anemia of chronic disease, sideroblastic anemia, Hgb E disease
Causes of macrocytic anemia
Megaloblastic anemia (Vitamin B12 or folate deficiency)
Causes of normocytic anemia
Sickle cell disease, anemia of chronic disease, aplastic anemia, hemolytic anemia
Conditions that cause increased reticulocyte counts:
1) Hemolytic Anemia: autoimmune hemolysis, RBC enzyme deficiencies, traumatic or angiopathic hemolysis, RBC membrane problems (spherocytosis, elliptocytosis)
2) 3-4 days after acute blood loss
3) Hemoglobinopathies
4) Toxin exposures
5) Hypersplenism
6) After tx of anemias: adequate doses of iron, folate or vitamin B12
Causes of decreased reticulocyte counts:
IDA, Aplastic anemia, Untreated megaloblastic anemia, radiotherapy, marrow tumors, myelodysplastic syndromes
What is the most common cause of IDA?
Chronic blood loss (GI bleed, menorrhagia)
What lab indicates hypochromic anemia?
Low MCHC
Mild IDA can be caused by:
Inadequate diet, normal or heavy menses, blood donation, malabsorption, increased requirements (growth, pregnancy), polycythemia tx with phlebootomy
Moderate to severe anemia can be caused by:
chronic blood loss, Peptic ulcer disease, varices, malignant dx, diverticulitis, severe menorrhagia, severe malabsorption
What products inhibit iron absorption?
Soy protein, bran, dairy, tea, coffee, calcium rich antacids, vegetable sources
What products enhance iron absorption?
Ascorbic acid (VIT C), citric acid, meat, poultry, fish, other (low iron stores of individual, low iron content of meal)
First line of tx for IDA:
Oral iron preparation; usually 150-200mg daily in divided doses
How long should iron therapy continue?
Empirically for 4-6 months or until the serum ferritin level exceeds 50mg/L
How should oral iron be taken?
30 min before meals with OJ
How long should it take for the Hgb level to rise after oral iron in IDA? MCV level?
Within 1-2 weeks; 1-2 months
When to refer IDA pt to hematologist:
non adherance to or intolerance of oral iron, persistent IDA, persistent microcytic anemia despite iron replacement and exclusion of other conditions.
What is the mainstay therapy for b-Thalassemia major?
Regular transfusions & Iron chelation therapy
What ethnicities are more likely to have a-Thal?
Southeast Asia, India, China, Philipines
What ethnicities are more likely to have b-thal?
Mediterranian, middle eastern, African, Asian
What is the difference between thalassemia and sickle cell on a blood smear?
Sickle cell - sickle shape
Thalassemia- target cells / aniocytosis (different sizes)
Lab values in beta minor:
Hct 28-40; MCV- 55-75; high levels of hgb A2 on hgb electrophoresis
Treatment for a or b minor thal?
genetics if planning family; education; Do NOT give Iron!
What differentiates Anemia of Chronic Disease (ACD) from IDA in lab values?
ACD: High Serum Ferritin, Low TIBC, High Transferrin sat; low reticulocyte count; more likely to be normocytic, but occasionally microcytic
Treatment for ACD?
Optimal control of underlying condition
What are the primary causes of macrocytic anemia?
Vitamin B12 deficiency & Folate deficiency (both are essential to normal DNA synthesis-bone marrow is sensitive to deficiencies)
Decreased dietary intake, alcoholism, and diseases associated with malabsorption are associated with ______________.
Folate deficiency
What is the most prevalent cause of vitamin B12 deficiency?
Pernicious anemia (lack of intrinsic factor)
What symptoms are specific to a severe vitamin B12 deficiency?
Marked anemia and neurologic deficits, sore mouth and loss of taste. Neuro sx may not go away with tx.
What lab can differentiate vitamin B12 deficiency from folate deficiency?
Methylmalonic acid(N=70-270) is elevated in B12 deficiency, but normal in folate deficiency. Homocysteine (N= 5-16) is elevated in both.
What can happen if you treat someone for folate deficiency that actually has B12 deficiency?
Can result in permanent neurologic or psych abnormalities.
