PATHOLOGY- Blood disorders Flashcards

1
Q

What are the 2 major components of blood

A
  1. Formed elements (45%)
  2. Plasma (55%)
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2
Q

What makes up the plasma in blood?

A
  1. Water
  2. Plamsa proteins
  3. Regulatory proteins
  4. Other sources
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3
Q

What makes up the formed elements of blood?

A
  1. Erythrocytes (99%)
  2. Leukocytes
  3. Platelets
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4
Q

What is another name for the former elements of blood?

A

Cellular component

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5
Q

What is hematocrit?

A

The proportion of whole blood that is made up of red blood cells

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6
Q

what is the equation to work out the haematocrit

A

% RBC / ratio of RBC volume to total BV

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7
Q

what is another word for haematocrit

A

packed cell volume (PCV)

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8
Q

What percentage of the blood is made up of hematocrits?

A

42-47%

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9
Q

What is the difference between plasma and serum

A

Plasma includes fibrinogen
Serum is plasma without fibrinogen (e.g. after blood clot)

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10
Q

What is the function of blood?

A
  1. Transportation of gases, waste, hormones and enzymes
  2. Fighting infection
  3. Homeostasis (Temperature, pH, volume)
  4. Haemostasis
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11
Q

How does the blood help with fighting infections?

A

It carries antibodies and leukocytes to site of infection

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12
Q

What is haemostasis?

A

Blood clotting

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13
Q

What is anaemia?

A

Haemoglobin concentration that is below a reference range for sex and age

usually a loss in RBC mass

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14
Q

when are there apparent [Hb] changes

A

when there are changes in plasma volume
plasma vol dec=apparent inc[Hb]
plasma vol inc=apparent dec[Hb]

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15
Q

how do you classify anaemia

A

By red cell size / volume (MCV)

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16
Q

Below what haemoglobin concentration would an adult be classified as anaemic?

A

Men: below 135g/L
Women: below 115g/L

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17
Q

What can anaemia be caused by?

A
  1. Reduced red blood cell mass
  2. Changes in plasma volumes
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18
Q

What can lead to changes in plasma volume?

A
  1. Dehydration
  2. Pregnancy
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19
Q

What are some of the symptoms of anaemia?

A
  1. Fatigue, breathlessness
  2. Angina
  3. Intermittent claudication
  4. Palpations
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20
Q

When can anaemia be asymptomatic?

A

When it develops slowly

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21
Q

How can we investigate anaemia?

A

Look at the

  1. Peripheral blood
  2. Blood film
  3. Bone marrow
  4. Haematinics
  5. Iron status markers
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22
Q

How do we use the peripheral blood to investigate anaemia

A

We can use:

  1. Red cell indices (Hb, MVC)
  2. White blood cell count
  3. Platelet count
  4. Reticulocyte count
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23
Q

What are haematincs

A

A nutrient required for haematopoesis e.g. Fe, B12, folate

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24
Q

Name the three nutrients haemantics usually refers to

A
  1. Iron (Fe)
  2. B12
  3. Folate
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25
Q

How do we classify anaemia ?

A
  1. By red cell size or volume (MCV)
  2. Underlying aetiology
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26
Q

What does MCV stand for

A

Mean corpuscular value

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27
Q

Name the different classifications of anaemia in regards to red cell size/ volume

A
  1. Microcytic anaemia
  2. Macrocytic anaemia
  3. Normocyctic anaemia
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28
Q

What is microcytic anaemia ?

A

Anaemia where the red blood cells are small
MCV is below 80

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29
Q

What is macrocyclic anaemia?

A

Anaemia where the red blood cells are large
MCV is greater than 96

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30
Q

What are the units for MCV?

A

Femtoliters

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31
Q

What is normocytic anaemia?

A

Anaemia where the red blood cells are normal sized
MCV is between 80-96

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32
Q

Name the different classifications of anaemia in regards to the underlying aetiology

A

Impaired production of red cells
- Haematinic deficiency (e.g. Fe, B12, folate) - most common

Increased loss of red cells
- e.g. haemolysis

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33
Q

What is an Haematinic deficiency?

A

Impaired production of red blood cells due to a deficiency in:
Fe
B12
Folate

most common

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34
Q

What is Haemolysis?

A

when blood breaks down abnormally

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35
Q

What happens if the Fe store balance in the body is disturbed

A
  • impairs the absorption capacity
  • increases the excretion
  • makes you vulnerable to Fe deficiency
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36
Q

what is hypochromic

A

small pale cells
MCH <27

MCH= Mean corpusucalr haemaglobin

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37
Q

If a patient comes in with microytic anaemia what diagnosis might you reach?

A
  1. Iron deficiency
  2. Thalassaemia
  3. Anaemia of chronic disease
  4. Sideroblastic anaemia
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38
Q

If a patient comes in with macrocytic anaemia and large bone marrow what diagnosis might you reach?

A

Vitamin B12 or folate deficiency

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39
Q

If a patient comes in with macrocytic anaemia and normal bone marrow what diagnosis might you reach?

A
  1. Alcohol reticulocytes
  2. Liver disease
  3. hypothyroidism
  4. drug therapy
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40
Q

If a patient comes in with normocytic anaemia what diagnosis might you reach?

A
  1. Acute blood loss
  2. Anaemia of chronic disease
  3. Chronic kidney disease
  4. Autoimmune rheumatic disease
  5. Marrow infiltration fibrosis
  6. Endocrine disease
  7. Haemolytic anaemia
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41
Q

Why is iron important in the body?

A

Iron is required for Hb synthesis

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42
Q

What is a normal cell sized mcv?

A

80-96

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43
Q

Name the most common type of anaemia

A

Iron deficiency anaemia

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44
Q

What causes iron deficiency anaemia

A
  1. Blood loss
  2. Increased demand eg pregnancy, growth
  3. Decreased absorption (due to surgery)
  4. Poor dietary intake
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45
Q

How can we investigate iron deficiency anaemia?

A

Look at:

  1. Blood count
  2. Blood film
  3. Iron status
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46
Q

What do we expect to see in the blood count in a patient with iron deficiency anaemia

A

Microcytic hypochromic cells

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47
Q

What does hypo chromic mean when describing cells?

A

Pale cells

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48
Q

What do we expect to see in the blood film in a patient with iron deficiency anaemia

A
  1. Poikilocytosis (variation in shape)
  2. Anisocytosis (variation in size)
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49
Q

Which proteins do we look for when looking at the iron status of a patient?

A

Ferritin and transferrin

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50
Q

Apart from iron deficiency anaemia what are the other causes of microcytic hypo chromic anaemia?

A
  1. Anaemia chronic disease
  2. Thalassaemia
  3. Sideroblastic anaemia
    (these are rare)
51
Q

Name the 2 terms we use to describe bone marrow

A

Megaloblastic
Normoblastic

52
Q

What is another name for vitamin B12?

A

Cobalamin

53
Q

What is the dietary requirement of vitamin b12?

A

2-3 micrograms a day

54
Q

Give examples of food that contains vitamin b12

A

Meat
Egg
Milk

55
Q

What does the body need to be able to absorb B12?

A

Intrinsic factor (IF)

56
Q

What is intrinsic factor secreted by?

A

Gastric parietal cells

57
Q

Where is vitamin b12 absorbed?

A

Small bowel

58
Q

Anaemia where red blood cells are small is called what? What would the MCV be?

A

Microcytic anaemia

MCV below 80

59
Q

Anaemia where red blood cells are large is called what? What would the MCV be?

A

Macrocyctic anaemia

MCV above 96

60
Q

Anaemia where red blood cells are ‘normal’ is called what? What would the MCV be?

A

Normocyctic anaemia

MCV 80-96

61
Q

How is vitamin b12 absorbed

A
  1. B12 taken in from food
  2. Binds to heptacorrin -> HC-Cbl
  3. Pancreas enzymes release Cbl
  4. Intrinsic factors from the gastric parietal cells binds to Cbl
  5. the intrinsic factor-Cbl complex is then absorbed in the small bowel
62
Q

What can cause vitamin B12 deficiency

A
  1. Pernicious anaemia
  2. Dietary- veganism
  3. Surgery
  4. Ileal disease
  5. Parasites
  6. Dtugs e.g. PPIs
63
Q

What causes pernicious anaemia?

A

Loss of cheif/ parietal cells
This decreases the concentration of intrinsic factor ultimately reducing B12 absorption

64
Q

Name the most common cause for vitamin B12 deficiency

A

Pernicious anaemia

65
Q

How can we investigate vitamin B12 deficiency

A

Look at:

  1. Blood count
  2. Blood film
  3. Bone marrow
66
Q

What would you expect to see on a blood count of a patient with vitamin B12 deficiency?

A

Macrocytic cells (MCV greater than 96)

67
Q

What would you expect to see on a blood film of a patient with vitamin B12 deficiency?

A

Oval macrocytes
Hyper-segmented polymorphs
Severe -> leukopenia (white blood cell loss)

68
Q

What would you expect the bone marrow to look like if a patient with vitamin B12 deficiency?

A

Increased megaloblasts
Immature red cell precursor cells

69
Q

How do we treat B12 deficiency

A

B12 injection

70
Q

Why does b12 deficiency cause macrocytic anaemia

A

As B12 needed for DNA synthesis without it you can get abnormal nuclear maturation/ cell division
Cells end up making more protein than DNA so balloon up and get big

71
Q

Which vitamins are needed for DNA synthesis?

A

Vitamin b12

Folate

72
Q

In which food is folate found?

A

Fruits and vegetables

73
Q

Why is folate important

A

Required for DNA synthesis

74
Q

Give some causes of folate deficiency?

A
  1. Malnutrition
  2. Malabsorption (Crohn’s disease)
  3. Increased demand (pregnancy, breastfeeding, cancer)
  4. Some drugs (some anti-epileptics)
75
Q

what is the most common cause of normocytic anaemia

A

haemolytic anaemia

76
Q

What is haemolytic anaemia?

A

When the lifespan of the red blood cell is shortened
Abonrmal breakdown of red blood cell

It can be hereditary or acquired

77
Q

Name some causes of Hereditary haemolytic anaemia

A
  1. Haemoglobin synthesis abnormalities e.g. sickle cell
  2. Red blood cell membrane defects
  3. Metabolic pathway defects
78
Q

Give an example of a haemoglobin synthesis abnormality

A

Sickle cell anaemia

79
Q

What causes sickle cell anaemia?

A

HbS single gene mutation

80
Q

Which gene is mutated in sickle cell anaemia

A

Valine for glutamic acid substituted 6th codon of beta-globin chain

81
Q

what causes the sickle shaped cells in sickle cell anaemia

A
  1. Abnormal form of Hb present -> HbS
  2. When there is low conc of O2, HbS molecules polymerise (stick together), deforming the red blood cells
  3. RBCs become sickle shaped cells
82
Q

What can make the effects of sickle cell anaemia cause a vaso occlusive crises (VOC)?

A

Infection
Dehydration
Cold
Acidosis
Hypoxia

83
Q

What can sickle cell anaemia result in?

A
  1. Decreased Red blood cell survival (haemolysis)
  2. Obstruction of small vessels and tissue infarction
84
Q

What are the clinical features of sickle cell anaemia?

A
  1. Anaemia
  2. Vaso-occlusive crises
  3. Acute chest syndrome (30% of patients)
  4. Long term complications
85
Q

Give examples of vaso-occlusive crises that are features of sickle cell anaemia

A
  1. Acute pain in the hands and feet (dactylitis)
  2. Severe pain femur, humerus, vertebrae, ribs and pelvis
  3. Hospital admissions due to pain
86
Q

What is acute chest syndrome?

A

Infection, fat embolism from necrotic marrow or pulmonary infarction
Can lead to shortness of breath, chest pain and hypoxia

87
Q

What would you expect to see on a blood count for a patient with sickle cell anaemia?

A

Normocytic normochromic anaemia

88
Q

What would you expect to see on a blood film for a patient with sickle cell anaemia?

A

Sickled red cells

89
Q

How do you treat sickle cell anaemia?

A

We can’t treat it but we manage the symptoms depending on the complications

  1. Hospitalisation
  2. Supportive IV fluids
  3. Analgesia
90
Q

What are some of the oral manifestations of anaemia

A
  1. Angular chelitis
  2. Atrophic glossitis
  3. Recurrent aphthous stomatitis (RAS)
91
Q

What is angular chelitis

A

Soreness at corners of the mouth

92
Q

What is Atrophic glossitis

A

Smooth tongue

93
Q

What is Recurrent aphthous stomatitis (RAS)

A

Ulcers in the mouth that reoccur 10-14 days after healing

94
Q

What are Recurrent aphthous stomatitis (RAS) associated with?

A

Iron, B12 and folate deficiencies

95
Q

What is haemostasis?

A

Process by which blood clots at the sites of vascular injury

96
Q

Why is haemostasis important?

A

As circulating blood volume is finite

97
Q

Name the stages of haemostasis

A
  1. Vasoconstriction
  2. Primary haemostasis (Platelet plug formation)
  3. Secondary haemostaisis (fibrin meshwork)
  4. Clot stabilisation / resorption
98
Q

What is vasoconstriction and why is it important?

A

It is constriction of the blood vessels
It is important as it reduces blood flow

99
Q

What is secreted during vasoconstriction?

A

Neurogenic/ factor secretion eg endothelin

100
Q

What is primary haemostasis?

A

Formation of platelet plus

101
Q

How is the platelet plug formed in primary haemostasis

A
  1. Endothelial is damaged due to injury leading to exposure of collagen
  2. Von Willebrand factor binding occurs
  3. This induces platelets to adhere and activate changing in to a spiky shape
    4, Platelets secrete granules attracting more platelets
  4. Aggregate to form a platelet plug
102
Q

What is secondary haemostasis?

A

Deposition of fibrin meshwork

103
Q

What happens in secondary haemostasis

A
  1. Tissue factor is exposed
  2. Activates coagulation cascade
  3. Thrombin cleaves to fibrinogen converting it into fibrin which forms a meshwork
  4. This activates more platelets
  5. Red blood cells become trapped
104
Q

What is the importance of fibrin?

A

stabilises platelets and activates more platelets

105
Q

what is the coagulation cascade stimulated by

A

exposed tissue factor

106
Q

what does the coagulation cascade produce

A
  1. prothrombin converted in to thrombin
  2. thrombin then acts to convert fibrinogen into a fibrin clot (fibrin glues the platelets together)
107
Q

4 things that can cause defects in blood clotting

A
  • Vessel wall abnormalities
  • Platelet deficiency / dysfunction
  • Abnormal coagulation
  • Combinations of above
108
Q

What us the significance of factor VIII?

A

It is a cofactor for the coagulation cascasde
It converts fibrolgin into fibrin

109
Q

What is the significance of the Von Willebrand factor (vWF)

A

binds platelets but also factor VIII

110
Q

Name the 2 substances that are essential for blood clotting

A

Factor VIII
Von Willebrand factor (vWF)

111
Q

Give examples of hereditary disorders that can lead to abnormal coagulation

A
  1. Von Willebrand disease
  2. Haemophillia A
112
Q

Name the most common inherited bleeding disorder

A

Von Willebrand disease

113
Q

How is Von Willebrand disease passed on?

A

Autosomal dominent

114
Q

what are the 3 types of vW disease

A
  • T1 (80%) - JWF
  • T2 (20%) = dysfunction
  • T3 (rare/severe) = no WF
115
Q

What is Thombocytopaenia?

A

Platelet deficiency

116
Q

How are the platelets affected in Von Willebrand disease?

A

Normal platelet count but defective function

117
Q

How is Von Willebrand disease treated?

A
  1. Desmopressin (promotes Von Willebrand factor production)
  2. Plasma concentration infusions
118
Q

How is haemophilia A passed on and what does it affect?

A

X linked recessive

Causes factor VIII mutations leading to impaired coagulation

119
Q

What can a person with haemophilia A suffer from?

A
  1. Easy bruising
  2. Haemorrhage post trauma. surgery
  3. Spontaneous Haemorrhage
120
Q

How do we treat haemophilia A?

A

Infusion of factor VIII

121
Q

what is disseminated intravascular coagulation?

A

A Thrombohaemorrhagic disorder

122
Q

What is a Thrombohaemorrhagic disorder?

A

A disorder that results in excessive and widespread activation of coagulation leading to the formation of a thrombi in microvasculature

123
Q

Is disseminated intravascular coagulation a diagnosis?

A

NO you need to find and treat the underlying cause of this