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Hematology/Oncology > Hematology Basics (3) > Flashcards

Hematology Basics (3) Flashcards

1
Q

What is hematology

A

The study of blood and its components

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2
Q

What are the components of blood

A

Plasma - 55%
-salt, water, enzymes, antibodies

Red blood cells - 45%
-important for oxygen transport throughout the body

White blood cells and platelets - 1%
-WBCs - protection for infections
-platelets - coagulation proteins that allow body to manage clotting

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3
Q

What is hematopoiesis?

A

The production of ALL types of blood cells (includes formation, development, and differentiation of cells)

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4
Q

What are low and high platelet counts called?

A

Low - thrombocytopenia
High - thrombocytosis

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5
Q

What are low and high RBC counts called?

A

Low - anemia
High - polycythemia

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6
Q

What are low and high WBC counts called?

A

Low - leukopenia
High - leukocytosis

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7
Q

What lab values do we look at to see if a patient has anemia? (2)

A

Hemoglobin
Hematocrit (percentage of blood that is made up by RBCs)

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8
Q

What lab value do we look at to see if a patient has thrombocytopenia?

A

Platelets

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9
Q

What is pancytopenia?

A

deficiency of all three cellular components of the blood (red cells (Hgb), white cells, and platelets) - so we look at all 3 of these values

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10
Q

What is anemia?

A

Reduction in the bodies ability to transport oxygen to organs that need it
-can be due to reduction in hemoglobin or hematocrit (RBCs)

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11
Q

Anemia is more prevalent in which patients?

A

Patients with CKD
Older patients - over 65 yo
Women (bc of pregnancy and menstrual bleeding)
African descent (typically have lower Hgb values)

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12
Q

Which 2 factors may cause someone to have higher Hbg/RBCs

A

People who live at higher elavations have higher levels of hemoglobin

High endurance athletes have higher levels of RBCs

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13
Q

What is the lower limit of normal of hemoglobin for males and females

A

Males: 13 g/dL
Females: 11 g/dL

(anything below this, we start thinking about potential therapy for these patients)

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14
Q

National cancer institute anemia scale

A

Grades 1 - 5 … the higher the grade the lower the level of hemoglobin

Grade 1
-Hgb of 10 - < LLN (13 for males 11 for females)

Grade 2
-Hgb of 8 to <10

Grade 3
-Hgb of 6.5 to <8

Grade 4
-Hgb of <6.5

Grade 5
-Death

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15
Q

What is the role of RBCs? How does this relate to anemia?

A

RBCs pick up oxygen from the lungs and release CO2 into the lungs

Then they transport the oxygen to the rest of the body
-anemia is a disorder where a patient has tissue hypoxia due to a lack in this oxygen transport

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16
Q

Erythropoietin (EPO)

A

This is a hormone that is produced primarily in the kidney

It stimulates the synthesis/differentiation of erythroid progenitor cells (which are precursors for RBCs) (reticulocytes)

So EPO is important for the production of RBCs
(which is why people with CKD are more prone to anemia, since EPO is made mostly in the kidney)

17
Q

Mean corpuscular volume (MCV)

A

This is a lab value of the average size of the red blood cells
-used to determine if the cells are large or small

18
Q

Normoblastic vs megablastic

A

This refers to the shape of the RBC

Normoblastic = normal shape, which is circular/round

Megablastic is more of an oblong/oval shape

19
Q

Normochromic vs hypochromic

A

This refers to the color of the RBC

Normochromic = normal bright red color

Hypochromic = faded color (usually means there is less hemoglobin and therefore impaired oxygen carrying capacity)

20
Q

How does the body react to anemia? (3)

A

When a patient has anemia there is a decreased oxygen carrying capacity

The body tries to compensate by…
-increasing blood flow
-increasing RBC mass
-increasing oxygen unloading

This makes sense as it is explained by the relationship in this equation…
VO2 = 1.39 x Q x Hgb x (SaO2 - SvO2)
-if there is a decrease in Hgb, to keep VO2 the same, the body will try to increase Q (blood flow) and oxygen unloading (SaO2 - SvO2)

21
Q

Compensating for anemia - increase in blood flow

A

Because of decreased oxygen transport with anemia, the body tries to compensate by increasing blood flow (Q)

The heart pumps harder and faster resulting in increased cardiac output

This can result in tachycardia and murmurs/arrhythmias
And if it continues for a long period of time can lead to heart failure

22
Q

When the body compensates in the anemic state to increase blood flow, which organs get the blood?

A

The vital organs (the ones that desperately need blood to function)
-brain, heart, kidneys

23
Q

Compensating for anemia - increase in RBC mass

A

The body tries to increase the mass of RBCs to increase oxygen transport (to compensate for the anemic state)

In order to do that it increases the production of EPO in the kidneys (to increase production of reticulocytes)

Overtime this can lead to hyperviscosity in the blood, which can result in bone pain (pain occurs as bone marrow tries to expand to compensate for increased amount)

24
Q

What are some causes of anemia (5)

A
  1. Production defects
    -deficiency in EPO (seen with kidney disease)
    -seen in cancer patients
    -inability to produce RBCs
  2. Maturation defects
    -typically cancer associated (cancer kills bone marrow, where RBCs mature)
  3. Survival defects
    -RBC cannot survive after it is produced
    -Can be intrinsic (something is wrong inside the RBC that keeps it from surviving) or extrinsic (RBC is being attacked from the outside, e.g. a toxin)
  4. Sequestration
    -splenic sequestration, particularly in hemolysis - spleen takes up RBCs (causing anemia)
  5. Blood loss
    -hemorrhage, GI bleed, etc.
    -could be due to conditions that require a lot of blood work/labs
25
Q

Reticulocyte counts

A

Reticulocytes are immature RBCs
We don’t want RBCs to stay immature, so this value should typically be less than 1%

Patients who are constantly producing new RBCs (e.g. sickle cell anemia or another disorder where they need to be constantly replacing RBCs) may have an elevated reticulocyte count

Or if a patient is bleeding or undergoing hemolysis - they will have more reticulocytes since they are trying to compensate and create more RBCs for the ones they are losing

26
Q

Mean cell hemoglobin (MCH)

A

Measure of the weight of Hb in a single RBC.
(used to make sure there is adequate amount of hemoglobin)

27
Q

Mean cell hemoglobin concentration (MCHC)

A

measurement of the amount (weight) of hemoglobin in a single RBC compared to the volume of the cell
(used to see if the amount of hemoglobin present is appropriate for the size of the cell to carry the oxygen needed)

28
Q

Macrocytic vs microcytic anemia

A

Macrocytic (MCV > 100)
-RBCs are LARGER than normal
-caused by folic acid deficiency or vitamin B12 deficiency

Microcytic (MCV < 80)
-RBCs are SMALLER than normal
-caused by iron deficiency (which results in reduced hemoglobin synthesis)
-aka iron deficiency anemia (IDA)

Note - in both marco and microcytic anemia the cells may be normal shaped (normoblastic) but are larger or smaller in size

Note - normal sized cells are called normocytic (MCV 80-100)

29
Q

If we have a decreased RBC production, what is the first step/first thing to look at?

A

The size of the RBCs… are they….
-microcytic (MCV < 80)
-normocytic (MCV 80-100)
-macrocytic (MCV > 100)

30
Q

If RBCs are microcytic what should you consider next to determine the cause of decreased RBC production?

A

The color…
If they are normochromic (bright red)…
-genetic cause (we may or may not have to do anything about this)

If they are hypochromic (faded) …
-means they do not have enough Hgb (low MCH and MCHC)
-this could be IDA (iron deficency) or anemia of chronic disease (caused by CKD or chronic inflammatory state)

31
Q

If RBCs are normocytic what is likely the cause of decreased RBC production?

A

Bone marrow failure –> cancer related
Or associated with CKD

Or can occur if a patient has causes of both macrocytic and microcytic anemia (results in normocytic)

32
Q

If RBCs are macrocytic, what should be considered next to determine the cause of decreased RBC production?

A

Is the shape appropriate?

If they are megablastic…
-caused by folic acid or vitamin B12 deficiency

If they are normoblastic (normal shape) - the cause is harder to identify…
-can be due to alcohol use, liver disease, hyperthyroidism, HIV medications, valproic acid , or other random causes

Hematology/Oncology (17 decks)

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