Part 6: Care of Site Specific Side Effects: VI. Bone Marrow Depression

Bone Marrow Depression aka

1. Bone Marrow Suppression

2. Myelosuppression (fyi: myel/o = marrow)

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Bone Marrow Depression can start at doses of ____

20 Gy and above

I got 2 Bones

Hematopoietic System includes:

1. bone marrow

2. circulating blood

3. lymph nodes

4. thymus

5. spleen

2 types of bone marrow

red marrow

yellow marrow

term. Yellow Marrow

def. consists primarily of fat cells BUT does not supply mature cells to the circulation (so not very important for our purposes)

term. red marrow

def. supplies mature cells to the circulating blood

What is the primary effect of radiation on bone marrow?

A decrease in the # of stem cells

term. Stem Cell

def.

1. Immature cells from which a variety of mature cells can arise

2. A precursor cell that can develop into one of many mature cells

BMD is generally not a problem unless what?

25% of Red (active) Marrow is in the tx field

or

RTT is combined with chemo

% of of Red Bone marrow that gets treated in the following fields

1. Skull

2. Ribs/ Sternum

3. Pelvic Bones

4. Vertebrae

5. Scapula

6. Proximal Femur & Humerus

1. Pelvic Bones- 30%

2. Vertebrae-25%

3. Ribs/Sternum-20%

4. Skull 10%

5. Scapula 10%

6. Proximal Femur & Humerus 5%

Although BMD is not usually a big problem unless the the RTT is combined with chemo___ is recommended as a wise precaution

weekly blood counts

term. Neutropenia

def. a decrease neutrophil count

Mature Blood cells in order of descending radiosensitivity ( most sensitive to least)

Little Monkeys Play Everywhere

1. Lymphocytes

2. White Cells

3. Platelets

4. Erythrocytes

Why are RBC (erythrocytes) not very radiosensitive?

They have a slow mitotic rate

Immature RBCs are called

erythroblasts

Are erythroblasts radiosensitive or radioresistant?

they are even more radiosensitive than any mature Mature Blood Cell

(Mature/ Stem) Cells are more radiosensitive

Stem Cells

True or False: Any stem cell is going to be VERY radiosenstive

True

What is the most radiosensitive Blood Stem Cell?

Erythroblast

term. Anemia

Def. ↓ in the # of RBC, HCT, HGB

a decrease in the number of Red Blood Cells, Hematocrit, and Hemoglobin

What is the most common symptom of anemia?

Fatigue

Why is fatigue a common symptom of anemia?

It is caused by the lack of circulating oxygen in the blood cell

Interventions for anemia?

Maintain adequate hydration