Introduction to Anemias Flashcards
What is MCH?
- normal range
- condition(s) with low values
- condition(s) with high values
Mean corpuscular hemoglobin (MCH) is a measure of the average mass ofhemoglobinperred blood cell
–>Normal: 27–34 pg (picograms) of hemoglobin per RBC
–>Low values are seen in iron deficiency or thalassemia
–>High values seen in macrocytosis of any cause
What is MCHC?
- normal range
- condition(s) with low values
- condition(s) with high values
Mean corpuscular hemoglobin concentration (MCHC) is a measure of the concentration ofhemoglobinin a given volume of packedred blood cell.
–>MCHC: 32–37 g/dl
–>Low values are seen in iron deficiency or thalassemia
–>High values seen in hereditary spherocytosis
List the microcytic anemias
The presence of microcytosis usually reflects a decreased hemoglobin content within the RBC :
- Reduced globin production
- -Thalassemias
- -Hemoglobinopathies - Reduced heme synthesis
- -Lead poisoning
- -Sideroblastic anemias
- -> Congenital
- -> Acquired (Myelodysplastic Sydndrome -MDS) - Reduced iron availability
- -Absolute iron deficiency (iron deficiency anemia)
- -> Dietary
- ->Chronic blood loss
–Functional iron deficiency (anemia of chronic disease/inflammation)
List the normocytic anemias with decreased reticulocyte count.
Normocytic: MCV 80-100 fL
Decreased Reticulocyte Count
PRIMARY
- Aplastic Anemias
- Endocrine Disorders
- Leukemias
- Myelodysplastic syndromes (MDS)
- Marrow Infiltrative Malignancy
SECONDARY
- Anemia of Chronic Disease/ Inflammation
- Infections
- Chronic Renal Failure
EXOGENOUS
9. Medications
List the normocytic anemias with elevated reticulocyte count.
Normocytic: MCV 80-100 fL
- Acute hemorrhage
- Autoimmune hemolytic anemia
- Microangiopathic Hemolytic Anemias
- -> Hemolytic Anemia Syndrome (HUS)
- -> Thrombotic Thrombocytopenia Purpura (TTP)
- -> Disseminated Intravascular Coagulation (DIC) - Enzymopathies
- ->G-6-PD deficiency
- -> Pyruvate Kinase deficiency - Membranopathies
- -> Hereditary Spherocytosis
- -> Paroxysmal Nocturnal Hemoglobinuria (PNH)
- -> Elliptocytosis - Hemoglobinopathies
- -> Sickle Cell Disease - Infections
List the macrocytic anemias.
Macrocytic: MCV> 100 fL
- B12 deficiency
- Folate deficiency
- Medications
- Reticulocytosis
- Hypothyroidism
- Liver disease
- Alcohol
- MDS
CBC
What is the normal range for the RBC?
4.1- 6.1 M/ cmm aka million/ microliter
CBC
What is the normal range for hemoglobin?
- females
- males
Female: 11.2 -15.7 g/ dL
Male: 13.7- 17.5 g/dL
CBC
What is the normal range for hematocrit?
HCT: 40-52%
CBC
What is the normal range for MCV?
MCV: 80-100 fL
CBC
What is the normal range for MCH?
MCH: 27-34 pg
CBC
What is the normal range for MCHC?
MCHC: 32-37 g/dL
CBC
What is the normal range for RDW?
RDW: 11.5-14.5%
Define hematocrit.
Hematocrit (Hct) =the proportion ofbloodvolume (RBC+plasma) that is occupied byRBCs
–> If Hgb is adequate, Hematocrit= 3 x Hgb
Define hemoglobin.
Hemoglobin (Hgb) = the amount of hemoglobin in the blood, expressed in grams per deciliter (g/ dL
Define Anemia
Reduction in redblood cell mass.
Hemoglobin/Hematocrit level below the lower limit of defined “normal” range
Practical: the World Health Organization (WHO) definition of anemia:
Hgb less than 13 g/ dL in men and 12 g/dL in women
What is MCV?
Mean Corpuscular Volume
MCV is equal to the volume of all red blood cells divided by the number of red blood cells.
MCV= (HCT (%) x 10/ RB (millions/ microliter))
Normal = 80-100 fL
Can be measured, calculated, or estimated
Very useful in classifying anemia based on size of the red blood cells
In an normal rbc, what is the size of the central pallor?
In a normal red blood cell, the size of the “donut hole” should be about 1/3 of the cell.
Donut hole = Central Pallor
What is RDW?
Red Cell Distribution Width (RDW)
- -> Normal RDW range =11.5-14.5 %
- -> Helps identify mixed populations of cells (e.g. micro and normocytic)
–> No pathologic condition associated with a low RDW
What is anisocytosis?
↑RDW = anisocytosis (increased variability in RBCs size)
What is isocytosis?
- -> low RDW
- -> little variability in RBC size
What is the reticulocyte?
Definition: immature (young) red blood cell typically composing about 1% of the red cells in the human body.
–>Called reticulocytes because of a reticular (mesh-like) network ofribosomalRNAthat becomes visible under a microscope with special stains such asnew methylene blue.
–>Increased reticulocytes indicate
a hyperfunctioning bone marrow.
–>Inappropriately low reticulocytes indicate a marrow problem
What is the normal reticulocyte count?
Normally 0.5% to 2.0% (of total RBCs)
Absolute counts generally 25,000 to 75,000 cells/microL
In times of increased erythropoietin, percentage and absolute level should increase
What is RPI?
–>Tells you if the bone marrow adequately compensating for the degree of anemia
–>Corrects for the degree of anemia (i.e. the lower the Hct, the higher the retic count should be)
–>Corrects for changes in reticulocyte maturation time based on the degree of anemia (i.e. the lower the Hct, the shorter maturation time should be)
RPI > 3 = adequate response
RPI less than 2= inadequate response
2-3= grey zone
In the context of RPI, what does maturation represent?
The Maturation term represents the maturation time of RBC’s (in days, days spent in the blood) at various levels of anemia.
Maturation = 1.0 for Hct >= 40%. Maturation = 1.5 for Hct 30-39.9%. Maturation = 2.0 for Hct 20-29.9%. Maturation = 2.5 for Hct less than 20
Problem:
–>Two men, one with a Hct of 44 and another with a Hct of 23 have the same, “normal” reticulocyte count of 1.5%.
–>How do we account for the difference in Hct when interpreting the reticulocyte percentage?
RPI (Reticulocyte Production Index) = Reticulocyte percentage x (Hct/ normal Hct) ? Maturation Factor
Two anemic men, one with a Hct of 44 and another with a Hct of 23 have the same, “normal” reticulocyte count of 1.5%.
RPI= 1.5% x (44/45)/ 1= 1.5 (Normal)
RPI= 1.5% x (23/45) /2= 0.38 (Low)
What are the signs and symptoms of anemia
SIGNS OF HYPOXIA
Pale and cold skin
–>Presence of subconjunctival pallor is reason enough to check a CBC
–>No physical exam sign reliably rules out anemia.
Jaundice
Low BP
SYMPTOMS OF HYPOXIA
- Dizziness
- Lightheadedness
- Syncope
- Weakness!!
- Fatigue!!!
- Shortness of breath!!
- Palpitations
- Chest pain: esp with pre-existing CAD
- Heart attack
COMPENSATORY SIGNS
- Heart murmur- flow murmurs due to tachycardia and attempt to increase SV
- Rapid heart rate
- Rapid breathing
Ppl can be symptomatic at Hb of 5 g/dL or even at 9 (moderate)
Depends on function of other organs and the body’s ability to compensate
• When would you get a bone marrow biopsy?
If you have anemia AND another cell line (white blood cells or platelets) is also decreased….go where the money is …..consider a bone marrow biopsy
Sutton’s law: In medicine, the principle of going straight to the most likely diagnosis. The law is named for the bank robber Willy Sutton who was asked why he robbed banks and who replied “because that is where the money is” (or so the story goes).
A 70 year old man with a history of a gastric ulcer presents to the emergency department after vomiting up blood 30 minutes prior. The patient’s wife is an RN and she said the one liter basin that he vomited into was overflowing with blood. His abdomen hurts and he feel dizzy and clammy.
His vitals are Temp 98.3 HR 104 RR 22 BP 94/64
He appears pale and uncomfortable and has mild tenderness to palpation in the mid-epigastric area.
A stat CBC and type and screen are ordered.
What do you think his hemoglobin/hematocrit will be?
While you are getting good IV access (2 large bore IVs) and starting IV fluids, the CBC comes back:
WBC: 7.8 K (4-10 K) Hgb: 13.1 g/dL (nl male 13.7- 17.4 g/ dL) HCT: 36% (nl 40-52%) PLTS: 346 (nl 145-370K ) MCV: 85 fL
Can we just send him home?
No
- ->In acute blood loss, Hgb/Hct may lag
- ->750 -1000+ ml of blood = 15-20% of normal total blood volume
- ->He’s dizzy and hypotensive so he’s sick!
What physiological factors contribute to the development of anemia?
→ Poor nutrition
→ decreased EPO
→ Decreased bone marrow production
→ increased intravascular destruction or rbcs
→ Spleen: increased sequestration and destruction of rbcs
→ increased bleeding
How do you do an anemia workup?
PRINCIPLES OF ANEMIA WORK-UP
During the visit o Obtain a good history o Identify the comorbidities o Check the medications o Examine the patient o Look at the peripheral smear
Classification/ Categorization
o Different approaches and ways to categorize the evaluation:
–> Kinetic approach- Classify based on mechanism
Decreased RBC production
Increased RBC destruction
Blood loss
–> Morphologic approach- Classify based on size (MCV)
Microcytic
Normocytic
Macrocytic
Either way, a key aspect is the reticulocyte countàHow is the bone marrow responding?
Tests/ Procedures
o Send the appropriate blood work-up, e.g., iron studies, Vitamin B12, folate, TSH, etc.
o Obtain appropriate studies, e.g., CT scan of the thorax if there is a suspicion of lung cancer; colonoscopy if there is a history suggestive of lower GI bleeding.
