Practical Hematology

Bone Marrow Aspiration

27-10-2014

Bone Marrow (BM)

•BM is the soft, flexible, spongy tissue inside bones that helps form

blood cells.

Types of Bone Marrow

1. Red BM: Which consists mainly of hematopoietic tissues.

2. Yellow BM: Which consists mainly of fat tissues.

•At birth, all bone marrow is red. With age, more of it is

converted to the yellow type.

•Only around half of adult bone marrow is red.

•Red marrow is found mainly in the flat bones

(pelvis, sternum, ribs, scapulae) and in

the cancellous (spongy) material at the epiphyseal ends

of long bones (femur and humerus).

•Yellow marrow is found in the medullary cavity, the hollow

interior of the middle portion of long bones.

•In cases of severe blood loss, the body can convert yellow

marrow back to red marrow to increase blood cell

production.

•BM Composition (Anatomy)

1. Stroma (Network of connective tissues).

3. Sinusoidal capillaries.

4. Stem cells.

5. Adipose tissues.

•BM Cellular Components

1. Mesenchymal stem cell (Multipotent): which differentiate into

osteoblasts, chondrocytes, myocytes, adipocytes and beta-

pancreatic islets cells.

2. Hematopoietic stem cell (Pluripotent): which differentiate into

RBC, WBC and platelets.

BM Aspiration

•It is the removal of a small amount of BM in semi-liquid form for

examination.

•BM biopsy removes a small amount of bone and a small amount of

fluid and cells from inside the bone.

Procedure

1. Make the animal to be relax (using calmative).

2. Clean and sterilize the skin (shave if necessary).

3. A special needle with a tube attached to it that creates suction

should be used.

4. An aspirate needle is inserted through the skin using manual

pressure and force until the bone.

5. Once the needle is in the marrow cavity, a syringe is attached and

used to aspirate semi-liquid bone marrow.

6. Remove the needle, press the area and then a bandage should

apply to the skin.

7. The sample should be directly processed.

8. If several samples are taken, the needle should be changed

between the samples to avoid contamination.

9. simple analgesics can be used to ease soreness, which is

common for 2–3 days after the procedure.

10. Any worsening pain, redness, fever, bleeding or

swelling may suggest a complication and contamination.

11. Avoid washing or wetting of the procedure site for at

least 24 hours after the procedure is highly advised.

Sites for BM Aspiration

a. Human

1. Posterior iliac crest.

2. Sternum (breastbone).

3. Tibial plateu.

b. Equine, Bovine, Ovine and Caprine

1. Tibia.

2. Iliac crest.

3. Sternum.

Special Drill and needle for BM examination in large animals (equine and bovine)

c. Canine and Feline

1. Proximal humerus.

2. Proximal femur.

3. Wing of the ilium.

Special needle for BM aspiration in small animals

d. Lab Animals

1. Femur (mostly by flashing method).

2. Tibia.

e. Swine

1. Iliac crest (Tuber coxae).

2. Sternum.

3. Femoral epiphysis.

f. Avian

1. Proximal tibiotarsus

2. Femur.

3. Humerus.

Cautions Should be Considered During BM Aspiration

1. Allergic to any medications.

2. Pregnancy cases.

3. Bleeding problems.

4. Medications you are taking.

When the Test is Needed?

1. Look for the cause of problems with RBC, WBC, or platelets in

those who have conditions such as thrombocytopenia, anaemia,

or an abnormal WBC count.

2. Find blood disorders, such as leukemia, and multiple myeloma.

3. To find out if the cancer has spread and how much it has spread

to the bone marrow such as Hodgkin's lymphoma or non-

Hodgkin's lymphoma.

4. Disseminated bacterial or fungal infection.

5. Genetic or chromosome problem.

6. Suspicion of BM Toxicity.

7. Clinical trial of some drug and natural products.

8. Collect a sample of bone marrow for medical procedures, such as

stem cell transplantation or chromosomal analysis.

9. To get more information about hematopoiesis.

The Risks of BM Aspiration

1. Allergic reaction to anaesthesia.

2. There may be excessive bleeding at the puncture site.

3. Contamination and infection, which are very rare.

4. Long lasting discomfort.

•These risks are most oftenly associated with conditions that cause a

weakened immune system or low platelet count.

BM Tests

1. BM smear.

2. BM culture (needs special media, culture flask, and

incubator).