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Medicine Phase 2a Haematology > Anaemia > Flashcards

Anaemia Flashcards

1
Q

Define anaemia

A

Decrease of haemoglobin in the blood below the reference for the age and sex of the individual

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2
Q

2 general reasons for anaemia

A

Low red cell mass (RCM)

Increased plasma volume e.g.pregnancy

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3
Q

What is average normal lifespan of a RBC

A

120 days

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4
Q

Causes of anaemia

A

Reduced production from bone marrow or increased loss of RBCs i.e. by the spleen, liver, BM and blood loss

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5
Q

How can you determine if BM production of RBCs is the problem in anaemia

A

Reticulocyte count

count of immature RBCs in the bone marrow

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6
Q

What does reticulocyte count tell you about the anemia and red blood cells

A

If R count is low, production is the issue

If R count is high, removal is the issue

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7
Q

What would happen to Hb levels in blood in dehydration

A

Reduction in plasma volume and thus a falsely high haemoglobin (Hb)

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8
Q

3 major types of anaemia

A

Microcytic - low MCV or small size (<80fL)
Normocytic - normal MCV
Macrocytic - high MCV (>96fL)

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9
Q

What is MCV

A

Mean Corpuscular Volume (MCV) which is essentially the average volume of RBCs (or their size)

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10
Q

Consequences of anaemia

A

Reduced oxygen transport
Tissue hypoxia
Compensatory changes (increased tissue perfusion, increased oxygen transfer to tissues, increased RBC production)

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11
Q

Pathological consequences of anaemia

A 
Myocardial fatty change
Fatty change in liver
Aggravates angina and claudication 
Skin and nail atrophic changes
CNS cell death (cortex and basal ganglia)
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12
Q

Non-specific symptoms of anaemia

A
  • Fatigue, headaches and faintness
  • Dyspnoea and breathlessness
  • Angina (if there is pre-existing coronary disease)
  • Anorexia
  • Intermittent claudication
  • Palpitations
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13
Q

Signs of anaemia

A
  • May be absent even in severe anaemia
  • Pallor
  • Tachycardia
  • Systolic flow murmur
  • Cardiac failure
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14
Q

Main causes of microcytic anaemia

A
  • Iron deficiency anaemia - the MOST COMMON CAUSE WORLDWIDE
  • Anaemia of chronic disease
  • Thalassaemia
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15
Q

Rare causes of microcytic anaemia

A

Congenital sideroblastic anaemia

Lead poisoning

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16
Q

What is average daily intake of iron?

A

15-20mg

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17
Q

What % of dietary iron is absorbed in the duodenum

A

10%

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18
Q

What is iron used for in body

A

For formation of haem in haemoglobin

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19
Q

How is iron absorbed from gut

A

Iron ions are actively transported into the duodenal intestinal epithelial cells by the Intestinal Haem Transporter (HCP1).

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20
Q

What happens to most iron from the gut

A

Incorporated into haemoglobin

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21
Q

What happens to iron that’s not incorporated into haemoglobin

A

Stored in reticuloendothelial cells, hepatocytes and skeletal muscle cells as FERRITIN (most, found in plasma and most cells - esp liver spleen BM) or HAEMOSIDERIN (in macrophages of bone marrow, liver and spleen)

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22
Q

Why is more iron stored as ferritin than haemosiderin

A

Ferritin is more easily mobilised for Hb formation

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23
Q

What % of menstruating women show iron deficiency anaemia

A

14%

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24
Q

Causes of iron deficiency anaemia

A

Blood loss:
Menorrhagia, GI bleeding, Hookworm
Poor diet:
Especially in children and babies (but rarely in adults where there is poverty
Increased demands such as during growth and pregnancy
Malabsorption:
Poor intake - rare in developed countries
Coeliac disease

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25
Q

What is leading cause of iron deficiency anaemia worldwide

A

Hookworm

results in GI blood loss

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26
Q

Risk factors of iron deficiency anemia

A
  • Undeveloped countries
  • High vegetable diet
  • Premature infants
  • Introduction of mixed feeding delayed - since breast milk contains low iron
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27
Q

Iron deficiency anaemia pathophysiology

A

Less iron available for haem synthesis
Crucial for haemoglobin
production thus reduction in iron will result in a decrease in haemoglobin
and thus smaller RBC’s resulting in microcytic anaemia

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28
Q

Iron deficiency anaemia clinical presentation

A
  • *Brittle nails and hair
  • Spoon-shaped nails (koilonychia)
  • Atrophy of the papillae of the tongue (*atrophic glossitis)
  • *Angular stomatitis/cheilosis - Ulceration of the corners of the mouth
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29
Q

Iron deficiency anaemia differential diagnosis

A
  • Thalassaemia
  • Sideroblastic anaemia
  • Anaemia of chronic disease
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30
Q

Iron deficiency anaemia diagnosis

A

Blood count and film:
RBCs are microcytic and hypochromic. RBC also show Poikilocytosis and Anisocytosis

Serum ferritin:
Low - confirms diagnosis (but may be normal in malignancy or infection e.g. due to inflammation)

Low serum iron
Transferrin saturation falls below 19% means iron deficiency present
Serum soluble transferrin receptor number increases

Further investigations into cause of blood loss

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31
Q

What is meant by a RBC being hyppchromic

A

pale

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32
Q

What is difference between Poikilocytosis and Anisocytosis

A 
Poikilocytosis = variation in RBC shape
Anisocytosis = variation in RBC size
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33
Q

What happens to total iron-binding capacity in iron deficincy

A

TIBC rises

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34
Q

Treatment of Iron deficiency anemia

A

Find and treat cause
Oral iron: FERROUS SULPHATE
Parenteral iron e.g. IV iron or deep intramuscular iron in extreme cases such as severe malabsorption.

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35
Q

Side effects of ferous sulphate

A

Nausea, Abdominal discomfort, Diarrhoea/constipation, Black stools

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36
Q

If side effects of ferrous sulphate are bad, what can you give instead?

A

Ferrous Gluconate

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37
Q

What is second most common cause of anaemia

A

Chronic disease that leads to secondary anaemia (due to bone marrow also being sick)

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38
Q

What is most common anaemia in hospital patients

A

anaemia of chronic disease

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39
Q

What chronic infections are likely to result in anaemia

A 
Tuberculosis
Crohn's
Rheumatoid arthritis
SLE
Malignant disease
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40
Q

Pathophysiology of anemia from chronic infections

A
  • There is decreased release of iron from the bone marrow to developing
    erythroblasts (early RBC, before reticulocyte)
  • An inadequate erythropoietin response (cytokine which increases RBC production) to anaemia
  • Decreased RBC survival
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41
Q

Clinical presentation of anaemia from chronic infections

A
  • Fatigue, headaches and faintness
  • Dyspnoea and breathlessness
  • Angina if there is pre-existing coronary disease
  • Anorexia
  • Intermittent claudication
  • Palpitations
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42
Q

Diagnosis of anaemia from chronic infections

A

Low serum iron and TIBC (total iron-binding capacity)
Normal or raised serum ferritin due to inflammatory process
Normal serum transferrin receptor level
Blood count and film - RBCs are normocytic or microcytic and hypochromic as in Rheumatoid arthritis and Crohn’s

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43
Q

Treatment of anaemia from chronic infection

A

Treat underlying chronic cause
Erythropoietin - effective in raising Hb level and is used in anemia or renal disease and inflammatory disease e.g. rheumatoid arthritis and inflammatory bowel disease

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44
Q

Side effects of Erythropoietin as a treatment for anaemia

A

flu-like symptoms, hypertension, mild rise in the platelet count and thromboembolism

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45
Q

Clinical presentation of anaemia in general

A 
Fatigue
Lethargy
Dyspnoea
Faintness
Palpitations
Headache
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46
Q

**Main causes of Normocytic anaemia

A

Acute blood loss (commonest presenting)
Anaemia of chronic disease
Combined Haematinic deficiency (B12 or folate and iron deficiency)

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47
Q

Less common causes of normocytic anaemia

A

Renal failure
Pregnancy
Endocrine disorders

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48
Q

Diagnosis of normocytic anaemia

A

Normal B12 or folate
Riased reticulocytes
Hb down
Blood count and film - RBCs are normocytic

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49
Q

Treatment of normocytic anaemia

A

Treat underlying cause
Improve diet with plenty of vitamins
Erythropoietin injections

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50
Q

Normal male concentration of Haemoglobin in the blood

A

131-166g/L

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51
Q

Normal female concentration of Haemoglobin in the blood

A

110-147g/L

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52
Q

Normal male RBC size

A

81.8-96.3fL

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53
Q

Normal female RBC size

A

80-98.1fL

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54
Q

2 types of Macrocytic anaemia

A

Megaloblastic

Non-megaloblastic (normoblastic)

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55
Q

What is meant by megaloblastic macrocytic anaemia

A

Presence of erythroblasts with delayed nuclear maturation because of
delayed DNA synthesis - these are megaloblasts, they are large (i.e. high MCV) and have no nuclei

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56
Q

Anaemia: What do you do in practice?

A 
Thorough history and examination
FBC+film
Reticulocyte count
U/Es, LFTs, TSH
B12, Folate, Ferritin
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57
Q

How would you investigate B12 deficiency

A

IF antibodies
Schilling test
Coeliac antibodies

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58
Q

Causes of macrocytic anemia

A 
*B12/folate deficiency (megaloblastic)
Alcohol excess/liver disease
Hypothyroid
HAEMATOLOGICAL:
-Antimetabolite therapy
-Haemolysis
-Bone marrow failure
-Bone marrow infiltration
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59
Q

What type of anaemia is iron deficiency anaemia

A

Microcytic

60
Q

**What type of anaemia is pernicious anaemia

A

Macrocytic

Megaloblastic

61
Q

What is pernicious anaemia

A

Lack of RBCs due to a lack of B12

62
Q

Clinical presentation of pernicious anaemia

A

Anaemia: Fatigue, Lethargy, Dyspnoea, Faintness, Palpitations, Headache
B12 deficiency: neurological problems:
-Symmetrical paresthesia (burning or prickling pain, tingling) in fingers and
toes
- Early loss of vibration sense and proprioception
- Progressive weakness and ataxia

63
Q

Pathophysiology of pernicious anaemia

A

Absorption of B12 occurs in the terminal ileum and requires Intrinsic factor for transport across intestinal mucosa.
IF is deficient in pernicious anaemia.
Causes megaloblastic anaemia.
Parietal cell antibodies in serum in 90% of patients. IF antibodies found inonly 50%.
Achlorhydria (reduced HCl production) possible.
Parietal cells of stomach are attacked due to autoimmunity causing atrophic gastritis

64
Q

Where is intrinsic factor release

A

Gastric parietal cells

65
Q

Aetiology of pernicious anaemia

A

Autoimmune destruction of parietal cells/Intrinsic factor

Also malabsorption or diet (vegan) may contribute

66
Q

Epidemiology of pernicious anaemia

A

1/10,000 in N europe

Peak age of 60

67
Q

Diagnostic tests of pernicious anaemia

A

Blood film: macrocytic RBC
Autoantibody: IF (intrinsic factor) antibodies

Serum B12 is low
Hb is low
Reticulocyte count is low
(serum bilirubin may be raised)

68
Q

Treatment of pernicious anaemia

A 
IM Hydroxocobalamin (Replenish stores of Vitamin B12)
If neuro involvement then refer to haemaologist.
Do NOT give Folic acid instead of B12, this leads to fulminant neurological deficit
69
Q

Risk factors of pernicious anaemia

A 
Elderly
Female
Fair-haired, blue eyes
Blood group A
Thyroid and Addisons disease
70
Q

Where do you find vitamin B12

A

Meat
Fish
Dairy products
(not plants)

71
Q

How long do stores of vitamin B12 last?

A

4 years

72
Q

How is B12 absorbed

A

By binding to intrinsic factor produced by gastric parietal cells, then being absorbed in the terminal ileum of small intestines.

73
Q

What is vitamin B12 used for?

A

Thymidine and DNA synthesis

74
Q

What types of anaemia is folate deficiency

A

Megaloblastic macrocytic anaemia

75
Q

Where in diet do you get folate

A

Green vegetables e.g. spinach, broccoli, nuts, yeast, liver

76
Q

How long do stores of folate last?

A

4 months

77
Q

Risk factors of folate deficiency anaemia

A 
Elderly
Poverty
Alcoholic
Pregnant
Crohn's or Coeliac disease
78
Q

Clinical presentation of folate deficiency

A

Anaemia: Fatigue, lethargy, dyspnoea, faintness, palpitations, headache
Folate deficiency: Develops over 4 months of deficiency (due to bodily reserves). Possibly depression. Glossitis.
(may be asymptomatic)

79
Q

Pathophysiology of folate deficiency

A

Folate is essential for DNA synthesis. Therefore in folate deficiency, there is impairment of DNA synthesis.
Results in delayed nuclear maturation, resulting in large RBCs as well as decreased RBC production in the bone marrow.
Folate also essential for fetal development

80
Q

Why is folate important for fetal development?

A

Deficiency can result in neural tube defects

81
Q

Main cause of folate deficiency anaemia

A
  • Main cause is poor intake due to dietary deficiency e.g. poverty, alcoholics and elderly.
  • Increased demand e.g. pregnancy or increased cell turnover i.e. haemolysis, malignancy, inflammatory disease and renal dialysis
  • Malabsorption e.g. coeliac disease or Crohn’s disease
  • Antifolate drugs e.g. methotrexate and trimethoprim
82
Q

How can you differentiate between folate and B12 deficiency

A

No neuropathy in folate deficiency - unlike B12

83
Q

Diagnosis of folate deficiency

A

Blood film: macrocytic

Erythrocyte folate levels: indicated reduced body stores (serum folate also low)

84
Q

Treatment of folate deficiency

A

Folic acid supplement.
Treat underlying cause.
Advise regarding folate deficiency in pregnancy

85
Q

Complications from untreated B12 deficiency

A

HF, angina, foetus development

86
Q

What type of anaemia is haemolytic anaemia

A

Normocytic

can be macrocytic if there are many young RBCs - which are larger and excessive destruction of older RBCs

87
Q

Where does haemolytic anaemia occur

A

Circulation (intravascular)

Reticuloendothelial system i.e. by macrophages of liver, spleen (espcially spleen) and bone marrow (extravascular)

88
Q

When RBC in circulation are destroyed, what is the Hb initially bound to?

A

Haptoglobulin

But soon these become saturated leading to excess free plasma Hb

89
Q

What happens to excess plasma Hb that is not bound to haptoglobulin

A

Filtered by the renal glomerulus and enters the urine, although small amounts are reabsorbed by the renal tubules.
In renal tubular cells, Hb is broken down and becomes deposited in cells as Haemosiderin

90
Q

What colour do reticulocytes stain on peripheral blood film?

A

with a light BLUE tinge

91
Q

What is larger out of reticulocytes and mature RBCs

A

Reticulocytes

92
Q

Consequences of haemolysis

A

Shortened RBC survival:

  • compensatory increase in RBC production by the bone marrow (can have Compensated haemolytic diseases)
  • BM can increase its output by 6-8 times by increasing the proportion of cells committed to erythropoiesis and by expanding the volume of active marrow
93
Q

By what process are RBCs made

A

Erythropoiesis

94
Q

**Main causes of haemolytic anaemia

A

RBC membrane defects - Hereditary spherocytosis
Enzyme defects - Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Haemoglobinopathies: B or A Thalassaemia, Sickle cell disease
Autoimmune haemolytic anaemia

95
Q

Haemolytic anaemia clinical presentation

A

Anaemia: Fatigue, lethargy, dyspnoea, faintness, palpitations, headache
Haemolytic:
Jaundice, gall stones, leg ulcers, signs of underlying cause

96
Q

Features of Haemolytic anaemia

A
  • High serum UNCONJUGATED BILIRUBIN
  • High urinary UROBILINOGEN
  • High faecal STERCOBILINOGEN
  • Splenomegaly
  • Bone marrow expansion
  • Reticulocytosis - increased reticulocytes
97
Q

What is the most common inherited haemolytic anaemia in Northern Europeans

A

Hereditary Spherocytosis
Autosomal dominant
Deficiency in SPECTRIN structural protein -> surface to volume ratio decreases and cells become spherocytic (more rigid and less deformable)

98
Q

Pathophysiology of haemolytic anaemia

A

RBCs are destroyed before usual 120 day lifespan.
BM provides compensatory reticulocytes.
RBC destruction can be extra or intra vascular.
Mostly extravascular, where cells are removed from the circulation by macrophages, particularly in the spleen.

99
Q

Aetiology of haemolytic anaemia

A

Inherited:
Red cell membrane defect (spherocytosis); Haemoglobin abnormalities; Metabolic defects
Acquired:
Autoimmune; Mechanical destruction; Secondary to systemic disease (liver failure); Infections (malaria)

100
Q

Epidemiology of haemolytic anaemia

A

Depends on underlying cause
Sickle cell mainly African people
Autoimmune is slightly more common in females

101
Q

Diagnostic tests of haemolytic anaemia

A

Reduced haemoglobin
Raised serum bilirubin and urinary urobilinogen

Spherocytes, Increased reticulocytosis (Blood film, blood count)

Increased MCV

Direct antiglobulin (Coombs test) to rule out an AI haemolytic anaemia if negative

102
Q

Treatment of haemolytic anaemia

A

Folate and iron supplement;
Immunosuppressive if autoimmune;
Splenectomy if hereditary spherocytosis or other approaches fail

103
Q

Complications of haemolytic anaemia

A

Cardiac failure

104
Q

What are spherocytes

A

Spherical RBCs

105
Q

What is ‘Aplastic’ anaemia

A

Lack of haemopoiesis as a result of bone marrow failure

106
Q

Clinical presentation of aplastic anaemia

A

Anaemia: Fatigue, lethargy, dyspnoea, faintness, palpitations, headache.
BM failure: Increased susceptibility to infection and bleeding

107
Q

Pathophysiology of aplastic anaemia

A

Reduction in the number of pluripotential stem cells along with a fault in those remaining or an immune response against them - meaning they are unable to repopulate.
Can occur in only one cell line, leading to isolated deficiencies

108
Q

Aetiology of aplastic anaemia

A

Congenital
Acquired (mostly)
Cytotoxic drugs
Infections

109
Q

Epidemiology of aplastic anaemia

A

2/1000000

More common in Asia

110
Q

Diagnostic tests of aplastic anaemia

A

FBC: Pancytopenia with low reticulocytes

BM biopsy: hypocellular marrow with increased fat spaces

111
Q

Treatment of aplastic anaemia

A

Removal of causative agent.
Cautious blood and platelet transfusion.
If not spontaneous recovery: BMTransplant or immunosuppressive therapy

112
Q

Complications of aplastic anaemia

A

Increased infection and bleeding

113
Q

What is the most common metabolic RBC disorder

A

Glucose-6-Phosphate dehydrogenase deficiency

114
Q

What is the importance of G6PD

A

Enzyme in the pentose monophosphate shunt that maintains glutathione in the reduced state.
AKA it’s vital for a reaction that is necessary for RBC’s by providing a NADPH which is used with glutathione to PROTECT the RBC from OXIDATIVE DAMAGE from compounds such as hydrogen peroxide

115
Q

Pathophysiology of G6PD deficiency

A

G6PD is an enzyme in the pentose monophosphate shunt that maintains glutathione in the reduced state.
This protects against oxidant injury in the RBC. Therefore lack of G6PD causes increased haemolysis.

116
Q

Inheritance pattern of G6PD deficiency

A

X-linked recessive

117
Q

Clinical presentation of G6PD deficiency

A 
Neonatal jaundice, (chronic) Haemolytic anaemia
Acute haemolysis (precipitated by fava beans)
118
Q

Diagnosis of G6PD deficiency

A

Direct measurement of enzymes in RBC:

e.g. G6PD enzyme levels (will be low)

119
Q

Treatment of G6PD deficiency

A

Avoid fava beans

Transfusion if necessary

120
Q

What makes up normal haemoglobin (HbA)

A

Haem
2 alpha chains
2 beta chains

121
Q

What makes up foetal haemoglobin (HbF)

A

Haem
2 alpha chains
2 gamma chains

122
Q

What makes up Haemoglobin delta (HbA2)

A

Haem
2 alpha chains
2 delta chains

123
Q

In an adult what % of RBCs are:
HbA (normal)
HbA2 (delta)
HbF (foetal)

A

HbA (normal) - 97%
HbA2 (delta) - 2%
HbF (foetal) - 1%

124
Q

What is Thalassaemia

A

Defective subunit of the haemoglobin complex

125
Q

Clinical presentation of thalassaemia

A

Variable
Alpha generally presents in utero; Beta in infancy
Can be asymptomatic if heterozygote
Homozygote may have severe anaemia, with failure to thrive and bone deformities due to hypertrophy of ineffective marrow)

126
Q

What type of anaemia is thalassaemia

A

Microcytic

127
Q

Types of thalassaemia

A

Beta Thalassaemia = Reduced B chain synthesis

Alpha Thalassaemia = Reduced A chain synthesis

128
Q

Pathophysiology of Beta thalassaemia

A
  • Little or no B chain production resulting in EXCESS ALPHA CHAINS
  • These excess alpha chains combine with whatever delta and gamma chains
    are produced
  • Resulting in increased HbA2 (Hb delta) and HbF (Hb gamma)
  • Defects are normally point mutations instead of gene deletions.
  • Mutations result in defects in transcription, RNA splicing and modification, translation via frame shifts and nonsense codons, producing highly unstable B-globin that cant be utilised.
129
Q

Different clinical presentations of Beta thalassaemia

A

Minor - heterozygous, asymptomatic, mild anaemia possible, RBCs are hypochromic and microcytic with a low MCV

Intermedia - symptomatic with moderate anaemia

Major - homozygous

130
Q

Minor beta-thalassaemia presentation and iron deficiency can be confused - how can you tell difference between the two

A

Serum ferritin and iron stores are normal in beta-thalassaemia

131
Q

Diagnosis of beta thalassaemia

A

Homozygous: Blood count and film
• Hypochromic microcytic anaemia
• Raised reticulocyte count
• Nucleated RBC in peripheral circulation

Haemoglobin electrophoresis shows increase HbF (gamma) and absent or less HbA (normal)

132
Q

Treatment of Thalassaemia

A

Homozygotes:
Blood transfusion to try and avoid complications.
Iron chelating agent for iron overload e.g. SC Desferrioxamine
Ascorbic acid increases iron excretion in urine, helps offset iron overload

More severe = BMT

133
Q

Example of an iron chelating agent

A

Desferrioxamine (SC)

134
Q

Diagnosis of thalassaemia

A

Either genetic testing or Hb electrophoresis (after identifying microcytosis)

135
Q

What can be given to increase iron excretion in urine

A

Ascorbic acid

136
Q

Epidemiology of thalassaemia

A

1% carriers of beta

5% carriers of alpha

137
Q

Pathophysiology of alpha thalassaemia

A
  • In contrast to beta-thalassaemia, alpha-thalassaemia is often caused by gene deletions
  • The gene for alpha-globin chains is duplicated on both chromosomes 16
  • The deletion of one alpha chain or both alpha-chain genes on each chromosome 16 may occur (deletion of one alpha chain is most common)
138
Q

Can you keep going?

A

Yes you fukin nutter

139
Q

Symptoms of Anaemia

A 
Fatigue
Lethargy
Dyspnoea
Palpitations
Headache
140
Q

Signs of Anaemia

A

Pale skin
Pale mucous membranes
Tachycardia (compensatory to meet demand)

141
Q

Side effects of Iron deficiency anaemia treatments

A 
Black stools
Constipation
Diarrhoea
Nausea
Epigastric abdo pain
142
Q

Signs of iron deficiency anaemia

A

Brittle hair and nails
Atrophic glossitis (inflamed/smooth tongue)
Kolionychia (spoon shaped nails)
Angular stomatitis (inflammation of corners of mouth)

143
Q

B12 and Folate deficiency anaemia can be referred to as megaloblastic anaemias. What does megaloblastic mean?

A

There has been an inhibition of DNA synthesis.

Means RBCs keep growing without division (no mitosis) => macrocytosis

144
Q

*Symptom of Haemolytic anaemia

A

Gallstones

145
Q

Signs of Haemolytic anaemia

A

Jaundice
Leg Ulcers
Splenomegaly
Signs of underlying disease (SLE Malar rash)

Medicine Phase 2a Haematology (16 decks)

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