Blood

Dr. Nithin Mathew – Gingiva
Contents
• Introduction
• Composition
• Functions of Blood
• Plasma Proteins
• Origin
• Forms of plasma proteins
• Variations in Plasma protein concentration
• Functions of plasma proteins
• Haemoglobin
• Structure
• Normal Values
• Functions
3

• Synthesis of Haemoglobin
• Catabolism of Haemoglobin
• Varieties
• Erythrocytes / Red Blood Corpuscles (RBC)
• General Characteristics
• Variations in size, shape and structure of RBC
• RBC indices
• Erythropoiesis
• Anaemias
• Pernicious Anaemia
• Folic Acid Deficiency Anaemia
• Iron Deficiency Anaemia
• Sickle Cell Anaemia
• Thalassaemia 4

• Leucocytes / White Blood Corpuscles (WBC)
• General characteristics
• Structure, Functions & Variations
• Leucopoiesis
• Platelets / Thrombocytes
• General Characteristics
• Count & Variations
• Thrombopoiesis/Megakaryocytosis
• Functions
• Coagulation of Blood & Bleeding Disorders
• Definition
• Mechanism of Haemostasis
• Clotting Mechanism
5

• Anticoagulant Mechanism
• Bleeding Disorders
• Blood Groups
• Classical ‘ABO’ blood groups
• Rhesus Blood Group
• Uses of blood grouping tests
• Significance of blood groups
6

Composition
• The human vascular system consists of approximately
70,000 miles of blood vessels.
• Blood vessels, along with the heart, are responsible for
the circulation of blood throughout the body.
• Maintains several functions in the body
• Total Blood Volume : 5 – 6 Litres (8% of total body weight
/ 80ml/kg body weight)
7

• Specific Gravity : 1050 – 1060
• Viscocity : 4 – 5 times that of water
• pH : 7.4 ± 0.05
• Blood, when allowed to stand, on settling, it will separate into two components
• Liquid – Plasma (55%)
• Solid – Formed Elements (45%) : RBC, WBC, Platelets
8

CELLS
• Cellular elements of blood – 45%
• Aka Packed Cell Volume (PCV) or Haematocrit
• Erythrocytes : 5 million/mL
• Leucocytes : 4000 – 11000 cells/mL
• Platelets : 1.5 – 4 lacs/mL
10

PLASMA
• Clear,straw colored fluid
• 55% of total blood volume
• 91% water
• 9 % solids
• 1% inorganic molecules : Na+, Ca2+, Cl-, HCO3
-,K+, Mg2+, Cu2+, PO4
3-
• 8% organic molecules : 7% plasma proteins, 1% Non-protein Nitrogenous
(NPN) substances, sugars, fats, enzymes, hormones
11

PLASMA
• Plasma proteins : 6.4 – 8.3 gm/dL
• 55% Albumin : 3 – 5 gm/dL
• 38% Globulin : 2 – 3 gm/dL
• 7% Fibrinogen : 0.3 gm/dL
• Prothrombin : 40 mg/dL
• Albumin : Globulin = 1.7 : 1
12

Non-protein Nitrogenous (NPN) substances : 28-4-mg/dL
• Derivatives of food and also waste products of tissue catabolism
• Includes:
• Urea : 20 - 40 mg/dL
• Uric Acid : 2 - 4 mg/dL
• Creatinine : 1 - 2 mg/dL
• Creatine : 0.6 - 1.2 mg/dL
• Xanthine : Traces
• Hypoxanthine : Traces
Other substances
• Neutral fats : 30 - 150 mg/dL
• Phospholipids : 150 - 300 mg/dL
• Glucose : 70 - 90 mg/dL
• Cholesterol : 120 - 200 mg/dL
13

Functions of blood
• Respiratory
• Transports oxygen from lungs to tissues and carbon dioxide from tissues to
lungs
• Nutritive
• Transports absorbed food materials, amino acids, fatty acids, vitamins, etc from
alimentary canals to tissues
• Excretory
• Transportsmetabolic wastes to kidney, skin and intestine for their removal
14

• Regulation of body temperature
• Blood preserves the very narrow range in body temperature with the help of
water since water has
i. High specific heat – buffers sudden change in body temperature.
ii. High conductivity – helps to take out heat from an organ for uniform
distribution throughout the body.
• Chemical for communication and protection
• Concentration of hormones and various substances in blood is regulated
through feedback mechanisms
• Defensive action against infections, initiation of inflammation and regulation of
haemostasis
15

• Plasma protein functions
• Exerts the osmotic pressure which influences the exchange of fluid between
blood and tissues
• Acts as reservoir of proteins
• Combines with many substances such as iron, thyroxine, steroid hormones, to
form transportable complexes from which the active components are released
16

Plasma Proteins
• Clear,straw colored fluid
• 55% of total blood volume
ORIGIN OF PLASMA PROTEINS
• Embryo: Mesenchymal cells through the process of secretion or dissolution of
their substances, form plasma proteins
• Adults:
i. Albumin from liver mainly
ii. Fibrinogen from liver
iii. Globulin from tissue macrophages, plasma cells and lymphocytes
17

FORMS OF PLASMA PROTEINS
• Normal plasma protein conc.: 6.4 – 8.3 gm/dL
Type Normal plasma level
55% 1. Pre-Albumin 0.03 gm/dL
2. Albumin 3 – 5 gm/dL
38% Globulin 2 – 3 gm/dL
7% Fibrinogen 200 – 450 gm/dL
Prothrombin 40mg/dL
18

Types of Globulin
i. 13% α-globulin (α 1; α 2) : 0.78 – 0.81 gm/dL
ii. 14% β-globulin (β 1; β 2) : 0.79 – 0.84 gm/dL
iii. 11% ϒ-globulin (ϒ 1; ϒ 2) : 0.66 – 0.70 gm/dL
Forms of Globulin
1. Glycoprotein: Carbohydrate + protein
2. Lipoprotein: α 2 –globulin + lipid, water-soluble complex with following subtypes..
I. High Density Lipoprotein (HDL) – contains 50% protein with large amount of
cholesterol and phospholipids.
II. Low Density Lipoprotein (LDL) – contains large amount of glycerides
III. Very Low Density Lipoprotein (VLDL) – they have higher proportion of fat in the
form of triglycerides or cholesterol
IV. Chylomicrons – contains 2% protein and 98% triglycerides
19

3. Transferin
• Normal conc.: 3-6.5 mg/dL
• Functions:
• Regulates and controls iron absorption
• Protects against iron intoxication
• Helps in iron transport
4. Haptoglobulins
• Normal conc.: 40 – 180 mg/dL
• Functions:
• Prevents loss of iron through urinary excretion
• Protects the kidney from damage by haemoglobin
• Regulates the renal threshold for haemoglobin
20

5. Ceruloplasmin
• Normal conc.: 15 – 60 mg/dL
• Binds with copper and helps in its transport and storage
6. Fetuin
• Present in foetus and new borns
• It is a Growth promoting protein
7. Coagulation factors
8. Angiotensinogen
9. Haemagglutinins
10. Immunoglobulin
21

Variations in plasma protein concentration
• Decrease:
- Haemorrhage results in loss of all forms of plasma proteins
- After haemorrhage, fibrinogen, globulin and albumin are regenerated and
complete restoration in few days
• Increase:
- Because of loss of more water from the plasma secondary to burns,
dehydration and diabetes insipidus
22

Variations in plasma protein concentration
Decrease in Albumin
• Physiological
 Infancy and newborns
 Pregnancy (during first 6 months). Globulin also decreases
• Pathological
 Impaired protein synthesis due to
oHepatitis, cirrhosis of liver, chronic diseases, severe malnutrition
 Excessive loss due to
oBurns, Nephrosis
23

Functions of Plasma Proteins
1. Helps in coagulation
• Due to presence of fibrinogen, prothrombin and other clotting factors
2. Helps to maintain colloidal osmotic pressure (COP) across capillary wall
• COP across capillary walls helps to maintain the exchange of fluid at tissue
level
• The rate of fluid exchange
( ie filtration-absorption) at any
point along a capillary depends
upon a balance of forces called
Starling Forces.
24

3. Helps in maintaining viscosity of blood
• Since 80% of total plasma concentration is due to albumin, and fibrinogen
is present on traces, blood viscosity is maintained at low level.
4. Helps in maintaining systemic arterial blood pressure constant
• Plasma proteins maintain the blood pressure constant by maintaining the
viscosity of blood.
5. Provides stability to blood
• Due to presence of globulin and fibrinogen
• If blood loses its stability, lead to Rouleaux formation
25

6. Helps in maintaining acid-base balance in the body
• Plasma proteins act as buffers
• Buffering capacity is 1/6th of total buffering capacity of blood
• Amphoteric in nature : behave as both acids and bases depending on
conditions
7. Transport and Reservoir function
• Plasma proteins form loose bond with hormones, drugs and metals to serve as
reservoirs and from which they are released slowly at appropriate sites.
26

Haemoglobin
• Red, oxygen carrying pigment in the RBCs
• Consists of protein Globin united with the pigment Haeme
STRUCTURE
• Consists of:
• 4 globin molecules: consists of 2 α and 2 β chains
• Each α chain contains 141 amino-acids
• Each β chain contains 146 amino-acids
• 4 heme molecules: Transport oxygen
• Iron is required for oxygen transport
• Each chain is associated with one haeme group
• There are 4 haeme to 1 molecule of haemoglobin, so
it can carry 4 molecules of oxygen.
27

NORMAL VALUES
• At birth: 23gm/dL (since RBC count is more)
• At the end of 3 months: 10.5gm/dL (since infant is milk fed which is devoid of
iron)
• After 3 months: haemoglobin increases gradually
• At the end of 1 year: 12.5gm/dL
• Adults:
• Males: 14 – 18 gm/dL
• Females: 12 – 15.5 gm/dL
• Clinically 14 – 18 gm/dL irrespective of sex is regarded as 100% haemoglobin
29

Some Definitions of Haemoglobin
• OxyHaemoglobin
• When Hb reacts with oxygen to form Oxyhaemoglobin
• Affinity of Hb for oxygen is influenced by pH, temperature and concentration of
2,3 diphospho-glycerate (2,3 DPG) in the RBCs, a product metabolism of
glucose.
• CarbaminoHaemoglobin
• Carbon dioxide reacts with haemoglobin to form carbaminohaemoglobin.
• Reduced (Deoxygenated) Haemoglobin
• Haemoglobin from which oxygen has been removed.
30

• CarboxyHaemoglobin
• Carbon monoxide reacts with haemoglobin to form carboxyhaemoglobin
• Affinity of Hb for Carbon monoxide is 210 times than its affinity for oxygen
which consequently displaces oxygen on haemoglobin, thus reducing the
oxygen carrying capacity of blood.
• Methemoglobin
• When reduced or oxygenated haemoglobin is exposed to various drugs or
oxidising agents, the compound is called methemoglobin.
• Disadvantages:
• It cannot unite reversibly with gaseous oxygen
• Dark colored and when present in large quantities in circulation, it mimics
cyanosis.
31

Functions
• Facilitate transport of oxygen from the lungs to the tissues
• Facilitate transport of CO2 from the tissues to the lungs
• Acts as an excellent acid-base buffer, being a protein. It is responsible for 70% of
buffering capacity of whole blood.
32

Synthesis of Haemoglobin
• Begins to be produced during the proerythroblast stage of the RBC cycle.
• The synthesis takes place in the mitochondria and ribosome by a series of
biochemical reactions.
• In the mitochondria, the synthesis of the heme portion of hemoglobin takes place.
Here, heme synthesis begins with the condensation of glycine & succinyl-CoA to
form δ-aminolevulinic acid (ALA).
• ALA then leaves the mitochondria and form porphobilinogen through a series of
reaction forms coproporphyrinogen. This molecule then returns to the
mitochondria and produce protoporphyrin.
• Proto-porphyrin is then combined with iron to form heme. Heme then exits the
mitochondria and combines with the globin molecule which is synthesized in the
ribosome.
33

Fate of Haemoglobin in the body
Haemoglobin
HAEMEGLOBIN
Remaining part Fe2+
BILIVERDIN
BILIRUBIN
FERRITIN
Tissue macrophage system
(Split off)
Oxidised by Haem Oxygenase
Reduced by Biliverdin Reductase
(Stored in liver)
Combines with APOFERRITIN
( tissue protein )
Reused for synthesis of
Haemoglobin
(Enters aminoacid pool)
(Excreted in bile)
(Split off)
35

Varieties of Haemoglobin
1. ADULT HAEMOGLOBIN (HbA)
• 2 types:
i. Haemoglobin A (α2β2)
ii. Haemoglobin A2 (α2δ2) :
• Here β chains are replaced by δ chains.
• The δ chains also contain 146 amino acids but 10 individual amino
acids differ from those in the β chain.
• It produces no abnormality and is regarded as normal haemoglobin
• HbA appears in foetus after 5 months of intrauterine life, when bone marrow
begins to function.
36

2. FOETAL HAEMOGLOBIN (HbF – α2ϒ2)
• Structure is same as HbA except that β chains are replaced by ϒ chains.
• ϒ chains also contains 146 amino acids but have 37 amino acids that differ
from those in the β chains.
• It is much more resistant to the action of alkalies than HbA.
• HbF has greater affinity for oxygen because of poor binding of 2,3 DPG to the
ϒ-polypeptide chain, so it can take much larger volume of oxygen than HbA at
low oxygen pressure.
• Life span is less (about 80days) compared to that of HbA (120days)
37

3. HAEMOGLOBIN-S (HbS)
• When HbS is reduced, it becomes much less soluble than HbA.
• Haemoglobin precipitates into crystals within RBC’s causing the following:
• Damages cell membrane producing increased fragility of RBC’s
• Crystals elongate and RBC’s become sickle shaped which decreases the
blood flow to the tissues due to sickling.
• This causes RBC’s to become more fragile producing severe anaemia
called sickle cell anaemia.
• Finally patient dies within a few days due to severe
anaemia and secondary infection
38

Erythrocytes / Red Blood Corpurscles
• RBC is a circular, biconcave, non-nucleated disc
• RBC cell membrane contains circular pores below which lies a contractile layer of
lipoproteins – spectrin : which maintains the shape and flexibility of RBC
membrane.
• Spectrin also contains the specific blood group antigen.
• Composition:
• 62.5% water
• 35% haemoglobin
• 2.5% sugar, lipids, protein, enzymes
39

• Diameter: 6.5-8.8 µm
• Thickness:
• Periphery: 2-2.4 µm
• At the centre: 1.2-1.5 µm
• Surface area: 140 µm2
• Volume: 78-94 µm3
• Count:
• At birth: 6-7 million cells/ mL
• Adults: Male – 5-6 million cells/ mL
Female – 4.5 – 5.5 million cells/ mL
• Life span: 120 days
40

Variation in Size, Shape & Structure
1. Anisocytosis: Variation in size of RBC
2. Poikilocytosis: Variation in the shape of RBC
3. Spherocytosis: Spherical RBCs; more fragile
4. Anaemia: Reduction in the number of RBS less than 4 million cells/ mL or their
haemoglobin content less than 12gm/dL or both
5. Polycythemia: RBC count increases more than 6 million cells/ mL
• Causes:
• Physiological
• At birth
• At high altitude due to chronic hypoxia
41

• Pathological
• Congenital heart diseases which produces hypoxia
• Dehydration
• Shock
• Tumour of bone marrow (Polycythemia Vera) [ 7-8 million cells/ mL]
6. At birth
• RBCs are larger in size and count is 6-7 million cells/ mL
• PCV is 54% since count is more
• Reticulocytes are 2-6% of RBC count. Decrease to less than 1% during first
week after birth after which they level and maintain throughout the life.
42

RBC Indices
They help in diagnosing the type of anemia.
MEAN CORPUSCULAR VOLUME (MCV)
• It is the volume of a single RBC in fL.
• MCV = PCV per 100ml blood × 10fL
RBC count in million cells/ mL
• Normal range: 78-94fL
• RBC with normal volume – Normocytes
• RBC with less than normal volume – Microcytes
• RBC with more than normal volume - Macrocytes
43

MEAN CORPUSCULAR HAEMOGLOBIN (MCH)
• It is the average amount of haemoglobin in a single RBC in picogram or micro-
microgram
• MCH = Haemoglobin in gm/dL × 10pg
RBC count in million cells/ mL
• Normal range: 28 - 32pg
• This index is not in use to find out the type of anaemia
44

MEAN CORPUSCULAR HAEMOGLOBIN CONCENTRATION (MCHC)
• It is the amount of haemoglobin expressed as percentage of the volume of RBC or it
is the haemoglobin concentration in a single RBC
• MCHC = Haemoglobin in gm/dL × 100
PCV per 100ml of blood
• Normal : 33% (33gm/100ml of cells)
• If MCHC is within normal range, then RBC is Normochromic
• If MCHC is less than normal range, then RBC is Hypochromic
• MCHC is never more than 38%, since cells cannot hold Hb beyond its saturation
point
45

COLOR INDEX (CI)
• Ratio of haemoglobin to RBC
• CI = Hb % = 100 = 1 (Range: 0.85-1.15)
RBC % 100
46

Significance of Absolute Values
• In Iron Deficiency Anaemia and Thalassaemia, MCV, MCH and MCHC are reduced.
• In anaemias due to acute blood loss and haemolytic anaemia, MCV, MCH and
MCHC are all within normal limits.
• In megaloblastic anaemia, MCV is raised above the normal level.
47

ERYTHROPOEISIS
Development of RBC is termed erythropoiesis
In Intrauterine life – 3 stages
1. Mesoblastic stage
• Early embryo upto 3 months of foetal life
• RBCs are formed from the mesoderm of yolk sac or area vasculosa.
• Since erythropoiesis occurs within the blood vessel, this stage is also called
intravascular erythropoiesis.
2. Hepatic stage
• After 3 months of foetal life
• Liver and spleen are the site of blood formation
• Nucleated RBCs develop from mesenchyme between blood vessels and tissue
cells
• This stage is also called extravascular erythropoiesis.
48

3. Myeloid Stage
• From middle of foetal life
• Erythropoiesis occurs in the bone marrow
• This stage is also called extravascular erythropoiesis.
In children
• All bones with red marrow
• Liver
• Spleen
In Adults
• After 18-20years, from red bone marrow
• Ends of long bones like humerus and femur
• Skull, vertebrae, ribs, sternum, pelvis
• If marrow is destroyed then liver and spleen become important sites of
blood formation
49

Terminology Cell Size Nucleus Cytoplasm Mitosis
Staining Haemoglobin
HAEMOCYTOBALST
(STEM CELL)
19-23 µm Very big – occupies whole of
the cell, 4-5 nucleoli
Rim all around the nucleus,
deep basophilic
Absent Mitosis
++
PROERYTHROBLAST 15-20 µm Occupies 3/4th of cell volume,
2-3 nucleoli
Slightly more in amount, deep
basophilic
Absent Mitosis
++
EARLY NORMOBLAST 14-16 µm Size decreases, no nucleoli Further increase in amount,
less basophilic
Absent Mitosis
++
INTERMEDIATE
NORMOBLAST
10-14 µm Nucleus size decreases Marked cytoplasm,
polychromatophilic staining
Starts appearing Mitosis
++
LATE NORMOBLAST
i. EARLY 8-10 µm Nucleus very small with
chromatin dot – Cartwheel
Appearance
Increases markedly Increases in
amount
Mitosis
stops
II. LATE 7-8 µm Nucleus degenerates,
becomes uniformly deeply
stained
Futher increases, more acidic,
less basophilic
Further Increases
in amount
Absent
RETICULOCYTE 7-8 µm No nucleus, remants of RNA
present
Acidophilic Further Increases
in amount
Absent
ERYTHROCYTE 7.2–7.4
µm
Nil Acidophilic Increases in
amount
Absent

52
Regulation of Erythropeisis

ANAEMIA
Definition
• Clinical condition characterised by reduction in the number of RBCs less than 4
million cells/mL or their content of haemoglobin less than 12 gm/dL or both
GRADING
• Mild Anaemia: Hb 8-12gm/dL
• Moderate Anaemia: Hb 5-8gm/dL
• Severe Anaemia: Hb less than 5gm/dL
53

CLASSIFICATION
1. Etiological classification
• Haemorrhagic: anaemia due to blood loss
• Dietary deficiency: due to iron, vitamins and proteins
• Dyshaemopoiesis or abnormal haemopoeisis resulting in aplastic anemia
• X-ray irradiations
• ϒ-ray irradiation
• Hypersenstitivity of bone marrow to drugs
• Haemolytic anaemias: due to excessive destruction of RBCs
54

2. Morphological or Wintrobe’s Classification
• Based on size of RBCs and its haemoglobin concentration
Normochromic Hypochromic
Normocytic i. After acute haemorrhage
ii. All haemolytic anemias except
Thalassaemia
iii. Aplastic anaemia
After chronic haemorrhage
Macrocytic All megaloblastic anaemias due to deficiency
of Vit. B12, folic acid or intrinsic factor
Secondary to liver disease
Microcytic Chronic infections i. Iron def. anaemia
ii. Thalassaemia
55

PERNICIOUS ANAEMIA / ADDISONS ANAEMIA
Pernicious means destructive or injurious
• Cause:
• Due to lack of intrinsic factor
• Failure of absorption of Vit. B12
Characteristic features
• Bone Marrow:
• Anaemia produces hypoxia which results in stimulation of erythropoiesis in
bone marrow with maturation arrest, so bone marrow becomes
hyperplastic
• This over activity of bone marrow is called Megaloblastic Anaemia
56

• Blood changes:
• RBC : Macrocytic Normochromic
• Count decreases markedly, less than 1 million cells/mL
• Hb content: less than 12gm/dL
• Diameter increases to 8.2 µm
• MCHC is usually normal because both MCV and MCH increase
• Peripheral smear shows nucleated RBC
• Reticulocyte count is increases more than 5%
• WBC and platelets both increase
• Changes in GIT:
• Deficiency of intrinsic factor
• Atrophy and destruction of gastric mucosa causing marked or complete lack of gastric
juice production (Achlorhydria)
• Soreness and inflammation of the tongue
• Loss of appetite
• Diarrhoea
57

• Changes in nervous system:
• Advanced cases, demyelination white fibres of spinal cord which affects the
dorsal column initially, later lateral columns – Subacute Combined
Degeneration of Spinal Cord
• This is associated with tingling and numbness in hands and feet, motor and
psychological disturbances.
58

FOLIC ACID DEFICIENCY ANAEMIA
Folic acid deficiency also produces Megaloblastic Anaemia
• Cause:
• Less dietary intake
• Poor absorption from GIT
• Increased demand (pregnancy)
• Antifolate drugs (anti-cancer drugs)
59

IRON DEFICIENCY ANAEMIA
Commonest anaemia in india
Definition:
Any Anaemia which responds to adequate dosage of iron is called iron
deficiency anaemia.
• Causes:
• Less dietary intake
• Increased loss:
• Acute haemorrhage
• Chronic hemorrhage
• Increased demand (infancy, childhood, pregnancy)
• Defective utilisation due to decreased absorption in diseases of stomach and
duodenum
60

• Characteristic Features:
1. RBC – Microcytic hypochromic
i. Count decreases or remains normal
ii. MCV,MCH,MCHC,CI decrease
iii. Life span – normal
iv. Peripheral smear shows anisocytosis and poikilocytosis
2. Bone marrow – Normoblastic hyperplasia
3. WBC and Platlets – normal count
4. Investigations
i. Serum bilirubin less than 0.4 mg/dL
ii. Serum iron decreases (normal: 60-160 µgm/dL)
iii. Total iron binding capacity TIBC – increases (normal: 150-350 µgm/dL)
61

5. Nails – dry, soft, spoon shaped
6. Tongue– angry red
7. CardioVascular/Respiratory system –
i. Early breathlessness
ii. Palpitations
iii. Repeated chest infections
8. Nervous system
i. Irritability
ii. Loss of concentration
iii. Headache
iv. Generalized body ache
v. Impotence
62

SICKLE CELL ANAEMIA
 A serious condition in which red blood cells can become sickle-shaped
 Normal red blood cells are smooth and round and so move easily through blood
vessels to carry oxygen to all parts of the body.
 Sickle-shaped cells don’t move easily through blood. They’re stiff and sticky and
tend to form clumps and get stuck in blood vessels.
 The clumps of sickle cell block blood flow in the blood vessels that lead to the limbs
and organs.
 Blocked blood vessel can cause pain, serious infection, and organ damage.
63

INHERITANCE of SICKLE CELL ANAEMIA
65
• If one parent has sickle cell anaemia
(HbSS) and the other is completely
unaffected (HbAA) then all the children
will have sickle cell trait.
• None will have sickle cell anemia.
• The parent who
has sickle cell
anemia (HbSS) can
only pass the sickle
hemoglobin gene
to each of their
children.
• If both parents have sickle cell trait
(HbAS) there is a one in four (25%)
chance that any given child could be
born with sickle cell anemia.
• There is also a one in four chance that
any given child could be completely
unaffected.
• There is a one in
two (50%) chance
that any given
child will get the
sickle cell trait.

Clinical Features:
• Most common symptom of anemia is fatigue (tired & weak)
• Shortness of breath
• Dizziness
• Headaches
• Coldness in the hands and feet
• Paler than normal skin or mucous membranes
• Jaundice
66

Complications:
• Hand-Foot Syndrome
• Splenic Crisis
• Infections
• Acute Chest Syndrome
• Pulmonary Hypertension
• Delayed Growth and Puberty in Children
• Stroke
• Eye Problems
• Gallstones
• Ulcers on the Legs
• Multiple Organ Failure
67

THALASSAEMIA
• Heritable, hypochromic anemias with varying degrees of severity
• Result of defective production of globin portion of hemoglobin molecule.
• May be either homozygous defect or heterozygous defect.
• Defect results from abnormal rate of synthesis in one of the globin chains.
• Globin chains are structurally normal, but have imbalance in production of two
different types of chains.
68

• Results in overall decrease in amount of hemoglobin produced and may induce
hemolysis.
• Two major types of thalassemia:
• Alpha (α) - Caused by defect in rate of synthesis of alpha chains.
• Beta (β) - Caused by defect in rate of synthesis in beta chains.
• Alpha thalassemia usually caused by gene deletion.
• Beta thalassemia usually caused by mutation.
69

Beta (β) Thalassemia
• Two types:
• Beta thalassemia minor
• Beta thalassemia major
BETA THALASSEMIA MINOR
• Caused by heterogenous mutations that affect beta globin synthesis.
• Usually presents as mild, asymptomatic hemolytic anemia unless patient in under
stress such as pregnancy, infection, or folic acid deficiency.
• Have one normal beta gene and one mutated beta gene.
• Hemoglobin level in 10-13 g/dL range with normal or slightly elevated RBC count.
70

• Anemia usually hypochromic and microcytic including target cells and
elliptocytes.
• Hepatomegaly or Splenomegaly are rarely seen.
• Have high Hb A2 levels (3.5-8.0%) and normal to slightly elevated Hb F levels.
• Normally require no treatment.
71

BETA THALASSEMIA MAJOR
• Characterized by severe microcytic, hypochromic anemia.
• Detected early in childhood:
• Infants fail to thrive.
• Have pallor, variable degree of jaundice, abdominal enlargement, and
hepatosplenomegaly.
• Hemoglobin level between 4 and 8 gm/dL.
• Severe anemia causes marked bone changes due to expansion of marrow space for
increased erythropoiesis.
• Characteristic changes are seen in skull, long bones, and hand bones.
72

• Physical growth and development delayed.
• Peripheral blood shows markedly hypochromic, microcytic erythrocytes with
extreme poikilocytosis, such as target cells, teardrop cells and elliptocytes.
• Hemoglobin electrophoresis shows
• Increased Hgb A2—delta globin production
• Increased Hgb F—gamma globin production
• Hyperbilirubinemia
• MCV in range of 50 to 60 fL.
• Iron overload—increased absorption and transfusions
• Endocrine disorders, Cardiomyopathy, Liver failure
73

Leucocyte / White Blood Corpuscles
• White cells, or leukocytes , exist in variable numbers and types but make up a
very small part of blood's volume--normally only about 1% in healthy people.
• Protect body against microorganisms and remove dead cells and debris
• Most are produced in the bone marrow from the same kind of stem cells that
produce red blood cells and others are produced in the thymus gland, which is at
the base of the neck.
• Individual white cells usually only last 18-36 hours before they also are removed,
though some types live as much as a year
74

Different types of leucocytes present in the circulation are:
Granulocytes
• WBC with granules in their cytoplasm
i. Neutrophils 50 - 70% 3000 - 6000 cells/mL
ii. Eosinophils 1 - 4% 150 - 300 cells/mL
iii. Basophils <1% 10 - 100 cells/mL
Agranulocytes
i. Lymphocytes 20 – 40% 1500 - 2700 cells/mL
ii. Monocytes 2 – 8% 300 - 600 cells/mL
75

Total Leucocyte Count (TLC)
• At birth: 20,000 cells/mL
count decreases after 2nd week and reaches normal in 5-10yrs
• In adults: 4000 – 11000 cells/mL
Leucopenia: TLC decreases less than 4000 cells/mL
• Causes:
• Starvation
• Typhoid
• Viral infection
• Bone marrow depression
76

Leucocytosis: TLC increases above 11000 cells/mL
• Causes:
• New born
• In the evening
• Exercise
• After injection of epinephrine or nor-epinephrine
• Stress
• Pregnancy
• Steroid administration
• Pyogenic or pyrogenic infections
Leukemia: cancerous condition of blood in which TLC is more than 50000 cells/mL
77

Structure, Function & Variations
Structure is seen by Leishman’s staining – haematoxylin-eosin stain
NEUTROPHIL
• Size: 10-14 µm
• Nucleus:
i. Purple in color
ii. Multilobed (1-6 lobes) – polymorphonuclear
iii. Young cells have horse-shoe shaped nucleus
iv. Older cells – multilobed, lobes are connected by chromatin threads
more the number of lobes, more mature is the neutrophil
78

• Cytoplasm:
i. Slightly bluish in color
ii. Granules
a. Fine sand like particles called ‘pin-point’ granules
b. Neutrophilic in nature (take both acidic and basic stains)
c. Contains variety of enzymes, so granules are regarded as lysosomes
d. Granulocytes liberate histamine and peroxidase enzyme which aids in
killing ingested bacteria
• Functions:
i. Phagocytosis : neutrophils are the first line of defence against bacterial
infections
ii. Contain fever producing substance – endogenous pyrogen
79

• Neutrophilia:
Causes
i. Physiological
a. Exercise
b. After injection of epinephrine
c. Pregnancy,menstruation, lactation
ii. Pathological
a. Acute pyogenic infections
b. Following tissue destruction
80

• Neutropenia:
Causes
i. In children
ii. Typhoid, paratyphoid fever
iii. Viral infection
iv. Bone marrow depression
81

EOSINOPHIL
• Size: 10-14 µm
• Nucleus:
i. Purple in color
ii. Bilobed – 2 lobes connected by chromatin thread
producing spectacle appearance
• Cytoplasm:
i. Acidophilic, slight pink in color
ii. Granular
iii. Granules
a. Coarse
b. Stain bright red with acidic dye
c. Granules do not cover nucleus
d. They contain peroxidase enzymes and lysozymes
82

• Functions:
i. Mild Phagocytosis
ii. They collect at sites of allergic reactions and limit their intensity by degrading
the effects of inflammatory mediators (histamine, bradykinin)
iii. They attack parasites that are too large to be engulfed by phagocytosis
• Eosinophilia:
Causes
i. Allergic conditions
ii. Parasitic infections
iii. Skin diseases
• Eosinopenia:
Causes
i. Seen after injection of ACTH or corticosteroids
83

BASOPHIL
• Size: 10-14 µm
• Nucleus:
i. Purple in color
ii. As in eosinophil
• Cytoplasm:
i. Slight basophilic, appears blue in color
ii. Granular
iii. Granules
a. Coarse
b. Stains purple or blue with basic (methylene blue) dye
c. Granules are plenty in number and overcrowd the nucleus
d. They contain histamine and heparin
84

• Functions:
i. Mild Phagocytosis
ii. Liberates histamine which leads to allergic reactions
iii. Liberates heparin which act as anticoagulant and keeps blood in fluid state
• Basophilia:
Causes
i. Chicken pox
ii. Small pox
iii. Tuberculosis
iv. influenza
• Basopenia:
Causes
i. Seen after administration of glucocorticoids.
ii. Drug induced reactions
85

LYMPHOCYTES
• Two types:
1. Large lymphocyte: 10-14 µm
2. Small lymphocyte: 7-10 µm
• Nucleus:
i. Single, very big, purple in color
ii. Shape: round, oval or indented
iii. Central position and occupies whole of the cell leaving marginal cytoplasm
iv. Nuclear chromatin is coarse and shapeless
• Cytoplasm:
i. Pale blue in color
ii. Scanty cytoplasm
86

• Functions:
Produces antibodies, specialy in delayed hypersensitivity
• Lymphocytosis:
Causes
i. In children – lymphocytes are more than neutrophils (Relative
Lymphocytosis)
ii. Chronic infections (Tb)
iii. Lymphatic leukemia
iv. Viral infections
• Lymphopenia:
Causes
i. Hypoplastic bone marrow
ii. AIDS
87

MONOCYTES
• Largest WBC
• Size: 10 – 18 µm with irregular outline
• Nucleus:
i. Pale staining
ii. Single
iii. Shape: round or indented (kidney shaped)
iv. Eccentric position and present on one side of the cell
v. Nuclear chromatin
• Cytoplasm:
i. Pale blue in color, clear
88

• Functions:
i. Active phagocytosis : second line of defence against bacterial infections
ii. Life span: approx. 3 months
iii. Monocytes also kill tumour cells after sensitization by lymphocytes
• Monocytosis:
Causes
i. Tuberculosis
ii. Syphillis
iii. Leukemias
• Monocytopenia:
Causes
i. Hypoplastic bone marrow
89

Leucopoiesis
90
Granulopoiesis:
• Granulocytes develop mainly and exclusively in the red bone marrow
• Wholly an extravascular process
• Marrow – Reticulum cells (irregular in outline, free from granules or
mitochondria with faint basophilic cytoplasm)
• Reticulum cells multiply by mitosis forming primitive WBCs (stem cells)
Agranulocytes:
• They develop to a slight extend in the bone marrow
• Main site or origin – lymphoid tissues (thymus, spleen, tonsils,etc.)

Terminology Cell Size Nucleus Cytoplasm Mitosis
PRIMITIVE WBC
(Stem Cell)
18-23 µm Large, spherical, many nucleoli,
open chromatin
Basophilic thin rim all around the
nucleus
Mitosis +++
MYELOBLAST 16-20 µm Large, pale, purple blue, many
nucleoli, fine stippled chromatin
Amount increases, narrow blue rim
without nucleus
Mitosis +++
MYELOCYTE – A
(Premyelocyte)
14-18 µm Size decreases, nucleoli
disappears, chromatin
condenses
Amount increases further Mitosis ++
MYELOCYTE – B
(Myelocyte
Proper)
12-16 µm Round, Nucleus size further
decreases
Amount increases, less basophilic,
granules appear with special
staining reaction, maximum
granules in neutrophils, scanty in
eosinophils and basophils
Mulitplication is
maximum
MYELOCYTE – C
(Metamyelocyte)
10-14 µm Nucleus very small with
chromatin dot – Cartwheel
Appearance
Amount further increases and
becomes more liquid, granules
show amoeboid movements
Mitosis stops
MATURE WBC
91

PLATLETS / THROMBOCYTES
93
• Smallest blood cells, colorless, spherical, oval or rounded granulated bodies
• Size: 2-5µm in diameter
• Volume: 5.8 µm3
• Leishmans’ staining shows a faint blue cytoplasm with distinct reddish purple
granules
• Nucleus is absent
• It contains various receptors meant for combining with specific substances like
• Collagen
• Fibrinogen
• Von-willibrand’s factor

• Cytoplasm:
i. Golgi apparatus
ii. Endoplasmic reticulum
iii. Few mitochondria
iv. Contractile proteins like actin & myosin – helps in clot retraction
v. Glycogen
vi. Lyzosomes
vii. Granules
• Dense granules: contain non-protein substances, ATP
• α-granules: contain clotting factors, PDGF
94

Count & Variations
95
• Normal: 1.5 – 4 lac cells/mL
• Circulating platelets: 60-75% of the platelet pool of the body
• Remaining are mostly in spleen – reservoir of platelets
• Life span: 8-12 days
• Destruction: mainly in spleen
• Thrombocytosis:
Causes
i. After administration of epinephrine due to splenic contraction
ii. After trauma
iii. Spleenectomy

• Thrombocytopenia:
Causes
i. Bone marrow depression
ii. Hypersplenism
iii. Viral infection
iv. Drug hypersensitivity
96

Thrombopoiesis / Megakaryocytopeiesis
97
• Site of origin: Bone Marrow Pluripotent stem cell
Committed stem cell
(polyploidy precursor cell)
Megakaryoblast (Stage 1)
Pro-megakaryocyte (Stage 2)
Granular megakaryocyte
(Stage 3)
Platelets

Functions of platelets:
i. Haemostasis:
Spontaneous arrest of bleeding by physiological process
Haemostasis mechanism includes:
• Platelet Adhesion:
• When blood vessels are injured, platelets adhere to the exposed
collagen present on the endothelial cells in the vessel wall
• Platelet Activation:
• Platelet binding to collagen initiate platelet activation
• Activated platelets: change shape, discharge granules and cause
platelet aggregation
98

• Platelet Aggregation:
• Increased by platelet activating factor (PAF) secreted by
neutrophils, monocytes and platelet cell membrane
• Platelet aggregation activatesPhospholipase ‘C’ which inturn
activates Phospholipase A2.
• This causes release of arachadonic acid from membrane
phospholipids which inturn gets converted to Thromboxane A2
and prostacyclin.
• Thromboxane A2 : increase in platelet aggregation along with
platelet adhesion and helps in the formation of temporary
haemostatic plug, causes stoppage of bleeding
• Prostacyclin : inhibits Thromboxane A2 formation and thus
prevents further platelet aggregation keeping platelet plug
localised.
99

ii. Blood Coagulation:
• The loose aggregation of platelets in the temporary haemostatic plus is
bound together and converted into definitive haemostatic plug by fibrin
iii. Clot Retration:
• Within 30mins of fibrin clot formation, clot retraction occurs
• Ie it contracts down to 40% of its original volume.
iv. Phagocytic function:
• Platelets help in phagocytosis of carbon particles and viruses.
v. Storage & Transport function:
• Platelets store histamine, which are released when the platelets
disintegrate and act on the blood vessel
104

COAGULATION OF BLOOD
105
Haemostasis:
• Spontaneous arrest or prevention of bleeding by physiological processes is
called haemostasis.
Major events that occurs in haemostasis are:
• Constriction of injured blood vessel
• Formation of a temporary haemostatic plug of platelets
• Conversion of temporary haemostatic plug into the definitive haemostatic clot

107
Clotting Factors
Factor I Fibrinogen
Factor II Prothrombin
Factor III Thromboplastin
Factor IV Ionic Calcium
Factor V Labile Factor
Factor VI -
Factor VII Proconvertin
Factor VIII Antihemophilic Factor
Factor IX Christmas Factor
Factor X Stuart prower Factor
Factor XI Plasma thromboplastin antecedent
Factor XII Hageman factor
Factor XIII Fibrin Stabilizing Factor

Anticoagulant Mechanism
109
• Factors that initiate the clotting mechanism also stimulate the dissolution of blood
clot, called Fibrinolysis.
• Fibrinolysis is due to the action of proteolytic enzymes ‘fibrinolysin’ or ‘plasmin’
• Present in circulation as inactive ‘plasminogen’ which gets converted to plasmin by
the action of thrombin and tissue plasminogen activator – TPA which is released by
tissue damage.
• Plasmin lyses the fibrin and fibrinogen, with the production of fibrinogen
degradation products

BLEEDING DISORDERS
111
Common causes of bleeding disorders can be classified as
1. Defective blood clotting due to:
i. Deficiency of clotting factors (I,II,V,VIII,IX,X)
ii. Deficiency of Vitamin K
iii. Anticoagulant overdose
2. Defective Capillary contractility – Purpura
3. Combined Defects

112
DEFECTIVE BLOOD CLOT
In this disorder, a firm clot is not formed following an injury during the period of
capillary contraction
Haemophilia
• Caused by an abnormality or deficiency of factor VIII.
• Aka Hemophilia A or Classic Haemophilia
• It is an inherited sex-linked anomaly due to an abnormal gene on X-chromosome
• Transmitted by females to males who manifest signs of the disease
• Gene responsible for Haemophilia is present in the X-chromosome

113
• In the presence of another normal X-chromosome, this gene acts as a recessive.
i.e. the individual has no signs of the disease but can transmit the disease.
• Hemophilia A is classified as mild, moderate, or severe, depending on the amount
of clotting factors in the blood.
Mild hemophilia 5–40 percent of normal clotting factor
Moderate hemophilia 1–5 percent of normal clotting factor
Severe hemophilia
Less than 1 percent of normal clotting
factor

114
Diagnosis
• Condition is characterised by a marked increase in clotting time (CT).
• Bleeding time is normal (2-5mins)
• Normal CT is about 3-8mins whereas Haemophilic blood takes 1-12 hours to clot
and may form only a soft clot.

115
Vitamin K Deficiency
• Vit K is required for the synthesis of prothrombin (factor II) and factors VII, IX and X
in the liver.
• Anticoagulants act by substrate competition by occupying vitamin K receptor sites.
• Vit K is absorbed from small intestine in the presence of adequate amounts of bile
salts.
• Gastrointestinal diseases, deficiency of Vit K occur as a result of poor absorption of
fats from the GI tract.

116
• Another reason is failure of the liver to secrete bile into the GI tract – Lack of bile
prevents adequate fat digestion and absorption which depresses Vit. K absorption
as well.
• Deficiency is characterised by prolongation of clotting time and serous
haemorrhages may occur.

117
DEFECTIVE CAPILLARY CONTRACTILITY
Clinical condition in which the capillary abnormality results in bleeding is known as
Purpura
Characterised by spontaneous haemorrhages beneath the skin, mucous membrane
and in internal organs.
Severe purpura with haemorrhages in the skin and from mucous membrane is called
Purpura Haemorrhagica
PURPURA
Two types of Purpura:
1. Primary (Idiopathic): congenital or hereditary and usually occurs in children
2. Secondary (Symptomatic): due to allergies, infections, drugs, cancer

118
Diagnosis
• Clotting time: Normal (3-8mins)
• Bleeding time: Increases
• Capillary endothelium resistance: decreases, causing increased capillary fragility
• Skin microscopy:
• In primary purpura: skin capillaries are very irregular and distorted in form.
After puncture these vessels remain patent, therefore free bleeding proceeds
from the needle track for several minutes
• In secondary purpura: capillaries are anatomically normal but because of the
presence of toxic agents or other causes, they do not contract effectively in
response to injury.
• Platelet count: normal (1.5 – 4 lacs/mL)
• In many cases, there was reported to be reduction in platelet count, called
Thrombocytopenic Purpura

119
Forms/Classification of Purpura
• Thrombocytopenic purpura:
• Purpura with low platelet count
• Results in poor clot retraction and poor constriction of injured blood vessel
• Clinically seen as:
• Mild: platelet count less than 50,000 cells/mL
• Moderate: platelet count less than 10,000 cells/mL
• Fulminating: platelet count less than 1000 cells/mL
• Athrombocytopenic purpura: purpura with normal platelet count
• Thromboasthenic purpura: due to abnormal circulating platelets but count is normal
• Haemorrhagic Telengiectasis: entirely due to localized capillary abnormality, which do not
contract with stimuli. Profuse bleeding will occur following rupture of these vessels

BLOOD GROUPS
120
• Experiments with blood transfusions, the transfer of blood or blood components
since hundreds of years.
• Austrian Karl Landsteiner discovered human blood groups
• Blood transfusions became safer.
• The differences in human blood are due to the presence or absence of certain
protein molecules called antigens and antibodies.
• The antigens are located on the surface of the RBCs and the antibodies are in the
blood plasma.

121
• Membrane of RBCs contains variety of blood group specific antigens called
agglutinogens.
• The antibody is present in the plasma called agglutinin.
• 30 commonly occurring antigens & hundreds of other rare antigens.
• Most of them are weak antigens.
• Each individual have different types and combinations of these molecules.
• Mixing incompatible blood groups leads to blood clumping or agglutination reaction,
which is dangerous for individuals.
• Isoagglutinins: antibodies that agglutinate blood cells of some individuals of the same
species.

122
• There are more than 20 genetically determined blood group systems known today
• Chief blood groups are
1. Classical ABO blood group
2. Rhesus (Rh) blood group

123
CLASSICAL / ABO BLOOD GROUP
• Individuals are divided into 4 major blood groups depending on the presence or
absence of blood group specific substance called A, B and O.
• A and B are group specific substances, polysaccharide in nature. – Antigens
(Agglutinogen)
• The antibody is present in each group – Agglutinin
• The agglutinin acting on agglutinogen A is called ‘α’ or Anti-A
• The agglutinin acting on agglutinogen B is called ‘β’ or Anti-B
• Group O doesn’t have agglutinogen as there is no corresponding agglutinin

124
• Agglutinins α & β are globulins of IgM type and hence cannot cross
the placenta
Based on these facts, Karl Landsteiner in 1901 framed the law called
LANDSTEINER’S LAW
1. If an agglutinogen is present in the RBC of an individual, the
corresponding agglutinin must be absent from the plasma.
2. If an agglutinogen is absent in the RBC of an individual, the
corresponding agglutinin must be present in the plasma.

126
INHERITANCE OF ‘ABO’ BLOOD GROUPS
• The Agglutinogen A and B are inherited as Mendelian dominant and first appear in
the sixth week of foetal life.
• Antigens A and B are not limited to the RBCs but are also found in any organs.
• The specific agglutinins are present in the plasma and appear at 10th day, rise to
peak at 10 years and then decline.
• The specific agglutinins act best at low temperature (5°C - 20°C) – COLD
ANTIBODIES
• The 4 classical ABO blood groups depend on 3 genes, named after the
corresponding factor A, B and O.

127
If a person receives a gene
from each parent
His blood group or
phenotype is
His Genotype is
A+A or A+O A AA• or AO*
B+B or B+O B BB• or BO*
A + B AB AB*
O + O O OO•
‘•’ – homozygous transmission
‘*’ – heterozygous transmission
• Each person’s blood group is determined by the two genes which he receives from
the parent.
• Six possible combinations of genes – AA, AO, BB, BO, AB and OO.
• Each combination is known as the genotype.

128
DETERMINATION OF CLASSICAL BLOOD GROUPS
• Determined by mixing a drop of isotonic saline suspension of the subject RBCs with
a drop of serum A and serum B separately on a glass side.
• Checked for agglutination reaction.

129
• If the blood agglutinates, it indicates that the blood have the antigens binding the
special antibody in the reagent.
• The agglutination indicates that the blood has reacted with a certain antibody and
therefore is not compatible with blood containing that kind of antibody.

130
BLOODTYPE Anti – A Serum Anti – B Serum
AB
+ +
A
+ –
B
– +
O
– –

131
RHESUS (Rh) BLOOD GROUP
• Discovered by Landsteiner and Weine in 1940
• Many people also have a so called Rh factor on the red blood cell's surface.
• The Rh antigen is called ‘D’ and its antibody is called Anti-D.
• Rh antigen-antibody reaction occurs best at body temperature – WARM
ANTIBODIES
• Rh antibodies are of IgG type and hence they can cross the placenta.
• Unlike ABO system (spontaneous reactions), Rh system – No spontaneous reactions

132
• 6 common types of Rh antigens, each of which is called an Rh Factor.
• They are: C, D, E, c, d and e
• A person who has a ‘C’ antigen does not have the ‘c’ antigen.
• A person missing the ‘C’ antigen always has the ‘c’ antigen.
• Same is the case with D-d and E-e antigens
• Type D antigen is the widely prevalent in population and is more antigenic than any
other Rh antigens.
• Anyone who has this antigen is said to be Rh positive, and who does not have are
said to be Rh negative.

133
• Rh negative individuals, the Anti-D are not actually present in the plasma but its
production can be triggered by:
i. Transfusion of Rh positive blood
ii. Entrance of Rh positive RBCs from the Rh positive foetus into the maternal
circulation of Rh negative mother – Haemolytic Disease of New Born /
Erythroblastosis foetalis

134
Rh factor and Haemolytic Disease
• Mother: Rh Negative
• Foetus: Rh Positive
• RBCs containing the antigen ‘D’ may cross the placenta from the foetus into the
mother either during pregnancy or during delivery.
• Mother responds: Anti-D which returns to the foetal circulation and begins to
destroy foetal RBCs.
• Degree of damage depends on the magnitude of maternal Anti-D response and the
ability of maternal Rh antibodies to cross the placenta.

136
• Since sensitization of Rh negative mother occurs at birth, the first child is usually
normal.
• But if the mother has been immunized previously by a Rh positive transfusion any
time even in childhood, a dangerously high response may occur during the first
pregnancy.
• This changes in the foetus is termed Hemolytic Disease of the New Born /
Erythroblastosis Foetalis.
• ABO incompatibilities rarely produce haemolytic disease of new born, since α & β
antibodies are IgM and cannot cross the placenta.

137
Clinical Picture of Erythroblastosis foetalis:
• New-born is jaundiced and usually anaemic at birth
• Anti-Rh antibodies from the mother circulate in the
infant’s blood for another 1-2 months after birth,
destroying more RBCs.
• Hematopoietic tissues of the infant attempt to replace the haemolysed RBCs.
• Liver and spleen become greatly enlarged.
• Severe anaemia usually causes death of the infant.
• Infants who survive develop permanent mental impairment or damage to motor
areas of brain – due to precipitation of bilirubin in neuronal cells causing
destruction.

138
Prevention of Rh Hemolytic Disease
1. Find out the Rh types of the expectant parents.
• If mother is Rh-negative and father is Rh-positive, baby is at risk for developing
HDN.
2. Mother's serum is tested to make sure she doesn't already have Anti-D anitbody
from a previous pregnancy or transfusion.
3. Finally, the Rh-negative mother is given a dose of Rh Immunoglobulin (RhIg) at 28
weeks of gestation and again after delivery, if the baby is Rh+.
The RhIg will attach to any Rh+ cells from the baby in the mother's bloodstream, thus
preventing them from triggering anti-D anitbody production in the mother.
The Rh- woman should also receive RhIg following a miscarriage, abortion, or ectopic
pregnancy.

139
Agglutination Reaction
• When bloods are mismatched so that anti-A or anti-B plasma agglutinins are mixed
with red blood cells that contain A or B agglutinogens.
• The red cells agglutinate as a result of the agglutinins’ attaching themselves to the
red blood cells.
• The agglutinins have two binding sites (IgG type) or 10 binding sites (IgM type).
• A single agglutinin can attach to two or more red blood cells at the same time,
thereby causing the cells to be bound together by the agglutinin.

140
• This causes the cells to clump, which is the process of “agglutination.”
• Then these clumps plug small blood vessels throughout the circulatory system.
• These agglutinated clumps of cells are later destroyed by the phagocytic
leucocytes, releasing haemoglobin into the plasma. – Hemolysis of RBCs.
• Released haemoglobin is converted by the phagocytes into bilirubin and later
excreted in the bile by the liver.
• Bilirubin level in the body increases - Jaundice

141
Patient: Type A
Patient: Type B

142
BASIC RULES TO BE FOLLOWED DURING BLOOD TRANSFUSION
• The plasma of the donor which contains the agglutinins can usually be ignored
because the donor’s plasma in the transfusion is usually diluted so by the much
larger volume of recipient’s plasma that it rarely cause agglutination.
• No Rh negative females at any age before menopause should ever be given a Rh
positive blood transfusion.
- This is because she may become sensitized by the injected Rh
positive blood and forms Anti-D antibodies.
- Transfusion may make her permanently childless

143
• Group A and group B can only safely receive blood from their own group and group
O
• Persons with group AB have no circulating agglutinins and can therefore be given
blood of anyone without developing a transfusion reaction.
• AB group : UNIVERSAL RECEPIENTS
• Persons of group O contain no agglutinogen and their blood can be given to
anyone, therefore its RBCs are not agglutinated by the members of the group.
• O group : UNIVERSAL DONORS
• The terms Universal donor and Universal recipient are no longer valid as
complication can be produced by the existence of Rh and other factors.
• Therefore, the only safeguard against blood transfusion is Direct Cross Matching.

144
DIRECT CROSS MATCHING
Importance of Cross matching: It is a direct and final check to detect whether there is
any mismatching between the bloods of potential donors and potential recipient.
• Major Cross Matching
• Donor’s RBCs are mixed with recipient’s serum
• Minor Cross Matching
• Recipient’s RBCs with donor’s serum
• Observed: if there is an agglutination or not.
• NO AGGLUTINATION: in either case means that the two blood are perfectly
COMPATIBLE: Transfusion is allowed.

145
DONOR’S BLOOD PATIENT’S BLOOD
MAJOR AND MINOR CROSS MATCHING OF BLOOD
Patient’s Plasma + Donor’s RBCs = Major Cross-Match
Donor’s Plasma + Patient’s RBCs = Minor Cross-Match
Plasma
RBCs

REFERENCES
146
• Textbook of Medical Physiology : Guyton & Hall
• Textbook of Human Physiology : A.K Jain

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