Introduction To Haematology

Question 1

Why haematology?

Answer 1

Blood is a major tissue/organ;
Many diseases affect blood;
Many haematological diseases;
Anaemias are common;
Drugs affecting clotting have a major role in management of cardiovascular diseases;
Haematological neoplasias require expert management;
Side effects of drugs may be haematological;

Question 2

Blood as a tissue

Answer 2

5 litres - 8% of body mass;
42-45% - RBCs;
1% - WBCs and platelets;
55-58% - plasma - water (90%), electrolytes, glucose, lipids, metabolites, gases, hormones, drugs, plasma proteins;

Question 3

Plasma proteins

Answer 3

Albumin - transport
Fibrinogen - clotting
Globulin - transport, clotting, precursors to hormones (angiotensinogen), defence;

Question 4

Serum

Answer 4

Coagulated plasma

Question 5

Red blood cells

Answer 5

Discoid (large SA to V ratio);
No nucleus;
Contains haemoglobin (35%) - oxygen, CO2 transport;
Lifespan - 120 days;

Question 6

Leucocytes - 5 types

Answer 6

Neutrophils -phagocytosis of microorganisms
Eosinophils - parasite killing and inflammation (allergic asthma)
Basophils - release histamine in hypersensitivity reactions;
Monocytes - phagocytic, leave blood and become macrophages;
Lymphocytes - produce antibodies

Question 7

Phagocytes

Answer 7

Granulocytes:
Neutrophils;
Eosinophils;
Monocytes

Question 8

Immunocytes

Answer 8

Lymphocytes

Question 9

Platelets (thrombocytes)

Answer 9

Cellular fragments;
Clot formation;
Non-nucleated;

Question 10

Blood cell production is known as and take place in?

Answer 10

Haemopoiesis;
Fetus + neonate - liver, spleen;
Neonate, child, adult - bone marrow;

Question 11

Control of WBC production

Answer 11

Colony-stimulating factors (CSF);
CSFs stimulated by infections;
Recombinant CSFs useful to improve reduced WBC counts after anti cancer drugs;

Interleukins also play a role

Question 12

Blood counts

Answer 12

Of great clinical value;
Cells per volume - counted by machine/manually;
Haemocrit (packed cell volume, PCV) centrifuge blood down- % that is RBC;
Haemoglobin - g per dl;
Used to identify anaemias;

Question 13

Mean corpuscular volume (MCV)

Answer 13

Volume of individual RBCs = haemocrit/RBC per litre (fl)
Useful to identify certain diseases:
Microcytic anaemia;
Macrocytic anaemia;
Alcohol abuse;

Question 14

Mean corpuscular Hb (MCH)

It is reduced when…

Answer 14

Hb/RBC;

Cell’s are small/ iron deficiency;

Question 15

Mean corpuscular Hb conc (MCHC);

Reduced when?

Answer 15

Hb/PCV;

Cells are large with impaired haem production (macrocytic anaemia);

Question 16

White cell and platelet counts:

• Philia (neutrophilia) -
• penia (neutropenia) -
• pancytopenia -

Answer 16

Increased neutrophil count;
Decreased neutrophil count;
Reduction in all cell counts;

Question 17

Platelets -
Increased:
Decreased:

Answer 17

Thrombophilia - increased thrombosis risk;

Thrombocytopenia - drugs, idiopathic;

Question 18

Leucocytes:
Increased:
Decreased:

Answer 18

Leucocytosis;

Leucopenia;

Question 19

Neutrophils -
Increased:
Decreased:

Answer 19

Neutrophilia - infection (bacterial/fungal infection); Trauma; inflammation;
Neutropenia - infection (viral, malaria), drugs;

Question 20

Eosinophils -

Increased:

Answer 20

Eosinophilia - allergy, parasites

Question 21

Monocytes -

Increased:

Answer 21

Monocytosis - infection (chronic eg. TB);

Question 22

Lymphocytes -
Increased:
Decreased:

Answer 22

Lymphocytosis - infection (bacterial/fungal), lymphoma;

Lymphopenia - inflammation, lymphoma, steroids;

Question 23

Blood groups determined by

Answer 23

Antigens on RBCs - antibodies to other antigens may be in plasma

Question 24

Types of blood groups

Answer 24

Type A - A antigens, b antibodies;
B - B antigens, a antibodies;
AB - AB antigens;
O - no A or B antigens, a and b antibodies

Question 25

Which blood groups are the most common?

Answer 25

O and A

Question 26

Clinically important blood groups?

Answer 26

ABO and Rhesus

Question 27

Which blood group is a universal donor for emergencies?

Answer 27

O negative

Question 28

Complications of wrong blood group transfusions

Answer 28

Acute hemolytic transfusion reactions

Question 29

Rhesus D (RhD) antigens

Answer 29

Either positive or negative; Important for pregnancy - haemolytic disease of the new born; Prevent with anti D immunisation - anti D immunoglobulin; Given to Mother after delivery of first child, binds to infant cells that have passed into Mother and prevents Mother raising antibodies;