Anemia (Taylor) Flashcards
Evaluation of Anemia
Erythron: Circulating RBCs and erythroid marrow (5 day maturation from BFU-E).
• 2L RBCs and 90mL marrow in 70kg male •
Reticulocyte – no nucleus – retains mitochondria, rRNA and hemoglobin synthesis 24-36 hours in circulation • Loss of these organelles in sinusoids of spleen
Mature RBC – 120 day lifespan until marked for destruction. Steady state, daily replacement of 0.83% of erythron (17 mL)
Oxygen Sensing-Hypoxia stimulates erythropoietin synthesis; done in the kidney
Erythropoiesis
Epo is made in the kidney and released in the blood stream then the bone marrow.
Hemoglobin
measured by absorption at 540 nM after cell lysis, the best measure of O2 carrying
RBC count
automated rbc counting when alter electrical conductance through aperture (x109/μL). Cells > 36 femtoliters in size and density of the cell
Hematocrit
volume blood composed of
RBCs. Calculated by RBC x MCV/10 and
reported in %. This is a calculated value!
aka packed cell volume
MCV (mean cell vol)
RBC size measured directly and
reported as a histogram. The mean rbc size is
reported as the mean cellular volume.
• Normocytic, microcytic (<80) or macrocytic (>100)
Mean Cellular Hemoglobin (MCH)
Calculated = hgb/RBC x 10. Few clinical uses.
Mean Cellular Hemoglobin concentration (MCHC)
Calculated = hgb/HCT x 100.
Normal 32-36 g/dL.
- MCHC < 32 = hypochoromic
- MCHC elevated in heretitary spherocytosis
Red cell distribution width (RDW)
Calculated value with normal range = 11.5% - 14.5%.
Reticulocyte count
% of all RBC (normal 0.8-1.5%)
Absolute reticulocyte count
– Relative reticulocyte count x RBC count
– Normal 25,000-90,000/μl
– Examples:
1.1% x 4.96 x106 = 55,000/μl
12.2% x 2.05 x106 = 250,000/μl
Anemia by Etiology
External blood loss – acute or chronic
• Increased destruction (hemolysis) – long
differential including toxin, RBC defect,
extra-erythrocytic damage (antibody, etc.),
splenic destruction
• Decreased production (hypoplastic) –
primary marrow failure, insufficient Epo,
injury (radiation), replacement (malignancy)
Classification of Anemia:
RBC Kinetics and Size 1
Macrocytic = MCV >100 fL
- Microcytic = MCV < 80 fL
- Hypochromic = MCHC < 32 g/dL
Classification of Anemia:
RBC Kinetics and Size 2
Macrocytic, normochromic anemia vs Normocytic, normochromic anemia
Macrocytic, normochromic anemia
– MCV >100 fL
– Megaloblastic (B12 or folate def., chronic AZT)
– Non-megaloblastic (drugs, liver disease,
hypothyroidism) – often with reticulocytosis
• Normocytic, normochromic anemia
– Acute blood loss, acute hemolysis, bone marrow
failure, chronic disease, hypersplenism
Microcytic, hypochromic anemia
MCV < 80 fL; MCHC <32 g/dL
– Iron deficiency
– Lead poisoning
– Thalassemia (can be normochromic)
– Chronic disease
Case 1:
19-year old male admitted hospitalized for an elective cholecystectomy.
- A consultation is requested to evaluate anemia noted with pre-operative testing. “Always been told by physicians has mild anemia”.
- Past medical history: Negative.
- Vitals signs normal. Mild icteric sclerae and palpable mass in the left upper quadrant below the costal margin. Remainder normal
cholecystectomy - hemoglobin is broken down to billirubin and excreted by the gall bladder
LUQ- spleen, destruction of red blood cells
Normocytic Anemia
Case 1 labs
Hemoglobin 11.2 g/dl
- Hematocrit 34%
- WBC 9.0, normal diff
- Platelet count 295,000/ul
- MCV 89 fl
• Absolute reticulocyte count 200,000 (29,500-87,300)
• Blood Smear Polychromasia, microspherocytes
micrspherocytes - HS or something causing hemolysis
normocytic
Case 1: Which of the following tests is most likely to help confirm the diagnosis?
A. Hemoglobin Electrophoresis
B. Osmotic Fragility Test
C. Direct and Indirect Antiglobulin (Coombs) test (autoimmunity)
D. Bone Marrow Aspiration and Biopsy (cancer maybe)
B. Osmotic Fragility Test
Hereditary spherocytosis
Normocytic anemia classifications
DETERMINE IF ADEQUATE BONE MARROW RESPONSE RELATIVE TO DEGREE OF ANEMIA
(ABSOLUTE RETICULOCYTE COUNT OF > OR = 100K)
normal BM
myelophistic anemia
absence space and fat globules
aplastic anemia
NORMOCYTIC ANEMIA:
WITH ADEQUATE RESPONSE
choice with reticulocytosis
acute blood loss or hemolysis
methylene blue stain: residual RNA
POLYCHROMASIA: INCREASED
RETICULOCYTES ON PERIPHERAL
SMEAR
NORMOCYTIC ANEMIA: HEMOLYSIS: extravascular
NORMOCYTIC ANEMIA: HEMOLYSIS
Intravascular
COMPLEMENT FIXATION
Example: PNH or paroxysmal
nocturnal hemoglobinuria. Acquired
somatic mutation in PIGA gene = no
GPI-linked membrane proteins like
CD55 (DAF or decay accelerating
factor). Complement fixation and
intense intravascular hemoloysis.
MECHANICAL FIXATION
EXOGENOUS TOXIC FACTORS
HB PRODUCTS IN BLOODSTREAM
Heme ring to biliverdin to bilirubin
extravascular vs intravascular hemolysis
NORMOCYTIC ANEMIA: CLASSIFICATION
WITH RETICULOCYTOSIS
Case 2:
42-year-old female with Systemic Lupus
Erythematosus (SLE) presents with fatigue
•Has been on Anti-TNF therapy and doing well
from lupus standpoint. However, she has
recently experienced worsening fatigue.
•Vital signs normal. Face and conjunctiva are
both jaundiced; she has a fading butterfly
rash on her face. The spleen is palpable on
deep inspiration.
HEMOGLOBIN 7.8 G/dL
- HEMATOCRIT 27%
- MCV 95 FL
- WBC COUNT 4.5, NORMAL DIFF
- PLATELET COUNT 450,000 /UL
- ABSOLUTE RETICULOCYTE 170,000 (29-87)
- ESR 25 MM/HR
- LDH 400 U/L (140-280)
- T. BILIRUBIN 3.5 MG/DL ((0.1-1.0)
- I. BILIRUBIN 3.0 MG/DL
Normocytic anemia
elevated reticulocyte count
LDH - some type of hemolysis is going on
neutrophils and spherocytes present= hemolysis
CASE #2
• WHICH OF THE FOLLOWING IS THE BEST
INTREPRETATION OF THE DATA?
A. The hemolysis is predominately intravascular.
B. The bone marrow is not responding to the anemia.
C. Direct Coombs testing should be positive.
D. Urine hemoglobin testing should be positive.
D. Urine hemoglobin testing should be positive. (Combs positive)
DIAGNOSIS: WARM AUTOIMMUNE HEMOLYTIC ANEMIA
ASSOCIATED WITH LUPUS
• EXTRAVASCULAR PROCESS