The Full Blood Count Flashcards

1
Q

Briefly describe the method used to count cells of the blood.

A

Flow cytometry:

1 - The blood is passed through a thin stream.

2 - A laser is shone through the stream, which scatters.

3 - The side scatter and forward scatter are measured.

4 - Side scatter measures complexity (presence of granules and nuclei), and forward scatter measures volume.

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2
Q

List 10 values measured in the full blood count.

Where possible, indicate how each value can be calculated.

A

1 - Haemoglobin concentration.

2 - Haematocrit.

3 - Packed cell volume.

4 - Red blood count.

5 - Mean cell volume (PCV / RBC).

6 - Mean cell haemoglobin (Hb / RBC).

7 - Mean cell haemoglobin concentration (Hb / PCV).

8 - Reticulocyte count.

9 - White blood cell differential count.

10 - Platelet count.

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3
Q

Define anisocytosis.

A

A condition in which red blood cells are of unequal size.

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4
Q

Define poikilocytosis.

A

A condition in which red blood cells are abnormally and irregularly shaped.

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5
Q

Define anisopoikilocytosis.

A

A condition in which red blood cells are both of unequal size (anisocytosis) and are abnormally and irregularly shaped (poikilocytosis).

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6
Q

Define acanthocytes.

A

A condition in which red blood cells have a spiky appearance.

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7
Q

Define codocyte.

A

A red blood cell with a bell-shape (AKA target cells).

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8
Q

What might cause an increased number of codocytes?

A

Liver disease.

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9
Q

Define dacrocyte.

A

A type of poikilocyte that has a teardrop shape.

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10
Q

Explain why nucleated red blood cells might appear in the blood.

A
  • After infancy, RBCs normally only contain a nucleus during the early stages of the cell’s life, and the nucleus is ejected as a part of cellular differentiation before the cell is released into the bloodstream.
  • So if nucleated RBCs are seen on an adult’s peripheral blood smear, it suggests that there is a very high demand for the bone marrow to produce RBCs, and immature RBCs are being released into circulation.
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11
Q

What might cause toxic neutrophils (neutrophils with abnormally large granules) to appear in the blood?

A

1 - Severe infection or inflammation.

2 - As a result of denatured proteins with rheumatoid arthritis.

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12
Q

Define left shifted neutrophils.

A

An increase in the number of immature neutrophils in the blood.

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13
Q

What is the term used to describe an excess of cells?

A

Polycythaemia.

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14
Q

What is the term used to describe a lack of cells?

A

Anaemia.

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15
Q

What are the two criteria used to classify anaemia?

A

1 - MCV.

2 - Cause (of decreased production / increased loss).

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16
Q

What is a relative polycythaemia?

Why might a relative polycythaemia arise?

A
  • Relative polycythemia is an apparent rise of the erythrocyte level in the blood; however, the underlying cause is reduced blood plasma.
  • Relative polycythemia can be caused by loss of body fluids, such as through burns, dehydration, and stress.
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17
Q

Define primary polycythaemia.

Give an example of a cause of primary polycythaemia.

A
  • Polycythemias due to factors intrinsic to red cell precursors.
  • Polycythemia rubra vera (PRV), or erythremia, occurs when excess red blood cells are produced as a result of a myeloproliferative disorder of the bone marrow.
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18
Q

Define secondary polycythaemia.

A

Polycythaemia caused by an increase in erythropoietin production.

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19
Q

What is the difference between appropriate and inappropriate secondary polycythemias?

A

Appropriate secondary polycythaemias arise due to appropriate / normal response of the kidneys to produce erythropoietin, whereas inappropriate secondary polycythaemias arise due to innappropriate / abnormal response of the kidneys to produce erythropoietin.

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20
Q

Give an example of a cause of secondary appropriate polycythaemia.

A

High altitude.

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21
Q

Give an example of a cause of secondary inappropriate polycythaemia.

A

Renal / liver tumours.

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22
Q

List 4 signs and symptoms of polycythaemia rubra vera.

A

1 - Plethoric (red) face.

2 - Aquagenic pruritis.

3 - Splenomegaly.

4 - Basophilia.

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23
Q

Which mutation is associated with polycythaemia rubra vera?

A

JAK2 mutation.

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24
Q

Which two conditions can polycythaemia rubra vera transform into?

A

1 - Myelofibrosis.

2 - Acute myeloid leukaemia.

25
Q

List 2 treatments of polycythaemia rubra vera.

A

1 - Venesection (bloodletting).

2 - Hydroxycarbamide.

26
Q

List 5 cells that are included in a white cell differential count.

A

Granulocytes (polymorphonuclear cells):

1 - Neutrophils.

2 - Eosinophils.

3 - Basophils.

Mononuclear cells:

4 - Lymphocytes.

5 - Monocytes.

27
Q

What is the primary function of neutrophils?

A

Phagocytosis.

28
Q

What is the primary function of eosinophils?

A

Destruction of large pathogens (e.g. parasites) by release of granules containing major basic protein (MBP).

29
Q

List 2 functions of basophils.

A

1 - Immediate hypersensitivity through IgE binding, histamine release and leukotriene release.

2 - Modulation of the inflammatory response.

30
Q

List the 3 types of lymphocyte.

A

1 - T cells.

2 - B cells.

3 - NK cells.

31
Q

List the two types of T cells.

A

1 - CD4+ cells (helper cells).

2 - CD8+ cells (cytotoxic cells).

32
Q

List 3 functions of T cells.

A

1 - Regulation of B cells.

2 - Destruction of virus, fungi and infected cells.

3 - Delayed hypersensitivity.

33
Q

List 2 functions of B cells.

A

1 - To produce antibodies.

2 - To present antigens.

34
Q

List 2 functions of NK cells.

A

1 - Lysis of antibody-coated cells.

2 - Destruction of tumours and virus-infected cells (without antibodies).

35
Q

List 2 functions of monocytes.

A

1 - Phagocytosis.

2 - To present antigens.

36
Q

List 4 causes of neutrophilia.

A

1 - Reactive (infective or non-infective).

2 - Tissue infarction.

3 - Demargination (movement of cells away from the margins of a blood vessel).

4 - Malignancies.

37
Q

List 7 causes of neutropenia.

A

1 - Ethnic neutropenia.

2 - Congenital neutropenia.

3 - Cyclical neutropenia (cycles of recurrent neutropenia).

4 - Reactive (especially viral).

5 - Bone marrow infiltration.

6 - B12 / B9 (folate) deficiency.

7 - Drugs.

38
Q

Define epitope.

A

The part of an antigen molecule to which an antibody attaches itself.

39
Q

What are the two types of expansion?

A
  • Polyclonal (many precursor cells usually in response to multiple antigens).
  • Clonal (one precursor cell).
40
Q

What is the most common lymphoproliferative disorder?

A

Chronic lymphocytic leukaemia.

41
Q

Give an example of risk factor for lymphoproliferative disorders.

A

Increasing age.

42
Q

List the symptoms of lymphoproliferative disorders.

A

Trick question!!! Often asymptomatic, requiring observation only.

43
Q

How are lymphoproliferative disorders controlled (if necessary)?

A

Chemotherapy.

44
Q

List 4 causes of lymphocytosis.

A

1 - Smoking.

2 - Splenectomy.

3 - Infection.

4 - Lymphoproliferative disorders.

45
Q

List 4 causes of lymphopenia.

A

1 - Reactive.

2 - Drugs.

3 - Congenital immunodeficiency.

4 - HIV.

46
Q

List 2 causes of monocytosis.

A

1 - Infection (especially EBV).

2 - Leukaemia.

47
Q

List 2 causes of monocytopenia.

A

1 - Marrow infiltration.

2 - Genetic defects in maturation (e.g. GATA2 transcription factor).

48
Q

List 3 causes of basophilia.

A

1 - Myeloproliferative disorders.

2 - Infection.

3 - Hypothyroidism.

49
Q

List 3 causes of basopenia.

A

1 - Steroids.

2 - Anaphylaxis.

3 - Hyperthyroidism.

50
Q

List 4 causes of eosinophilia.

A

1 - Parasitic infections.

2 - Atopy (predisposition towards allergic hypersensitivity reactions).

3 - Hypereosinophilic syndromes.

4 - Drugs.

51
Q

List 2 causes of eosinopenia.

A

1 - Alcohol.

2 - Steroids.

52
Q

What is the name of the precursor cells to platelets?

A

Megakaryocytes.

53
Q

Define thrombocytosis.

A

A condition where platelets are abnormally high.

54
Q

List 5 causes of thrombocytosis.

A

1 - Reaction (to an infection, inflammation or infarction).

2 - Splenectomy.

3 - Iron deficiency.

4 - Bleeding.

5 - Myeloproliferative disorders such as essential thrombocythemia.

55
Q

Which mutation is associated with essential thrombocythemia?

A

JAK2.

56
Q

List 9 causes of thrombopenia.

A

1 - Immune thrombocytopenic purpura.

2 - Thrombotic thrombocytopenic purpura.

3 - Disseminated intravascular coagulation.

4 - HELLP (haemolysis (H), elevated liver enzymes (EL) and low platelet count (LP)).

5 - Splenomegaly.

6 - Alcohol / liver disease.

7 - Bone marrow infiltration.

8 - Familial thrombocytopenias.

9 - von Willebrands disease.

57
Q

List 4 treatments of immune thrombocytopenic purpura.

A

1 - Steroids.

2 - Splenectomy.

3 - Rituximab.

4 - Azathioprine.

58
Q

What is the function of antiplatelet drugs?

A

To prevent clot formation.

  • They DON’T change platelet count.