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Module 103: The Heart, Lungs and Blood > Theme 2: Lecture 4 - Introduction to Anaemia > Flashcards

Theme 2: Lecture 4 - Introduction to Anaemia Flashcards

1
Q

Definition of anaemia

A

Hb concentration falls outside the normal range

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2
Q

What are the units of Hb

A

g/L

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3
Q

Clinical consequence of anaemia

A

Insufficient O2 delivery

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4
Q

Normal Hb range for children

A

110-160 g/L

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5
Q

Normal Hb range for women

A

115-165g/L

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6
Q

Normal Hb range for pregnant women

A

110-160 g/L

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7
Q

Normal Hb range for men

A

130-180 g/L

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8
Q

Haematocrit

A
  • % RBC volume to entire blood volume

- 40-45%

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9
Q

RBC count

A
  • Number of RBCs per litre

- 4x10^12/L

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10
Q

MCV

A
  • mean cell volume

- 80-100fL

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11
Q

MCH

A

mean cell Hb

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12
Q

MCHC

A

mean cell Hb concentration

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13
Q

Anaemia symptoms

A
  • Lethargy, fatigue
  • Shortness of breath (At rest vs On exertion?)
  • Palpitations
  • Headache
  • Worse symptoms if acute onset
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14
Q

Anaemia signs

A
  • Skin pallor
  • Pale conjunctivae
  • Tachypnoea
  • Tachycardia
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15
Q

Koilonychia

A
  • Spoon shaped nails

- due to iron deficiency

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16
Q

Causes of anaemia

A

Problems of inadequate synthesis:

  • Deficiency in necessary components
  • Bone Marrow Dysfunction / Infiltration e.g., myelodysplasia or aplastic anaemia

Problems of blood loss or consumption:

  • Bleeding
  • Haemolytic
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17
Q

myelodysplasia

A

one of a group of cancers in which immature blood cells in the bone marrow do not mature, so do not become healthy blood cells

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18
Q

aplastic anaemia

A

body fails to produce RBCs in sufficient number

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19
Q

How can anaemias be classified

A
  • Size of red cell
  • Acute or chronic
  • Underlying aetiology
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20
Q

What is the most common type of anaemia

A

Iron deficient

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21
Q

What causes iron deficiency

A

Bleeding:

  • Occult gastro-intestinal blood loss: (GI Malignancy (never miss this) and GI peptic ulceration)
  • Menstrual
  • Renal tract

Inadequate intake:

  • Dietary deficiency - Vegan/vegetarian diet
  • Malabsorption - Coeliac and Crohn’s disease

Increased requirements:
-Pregnancy

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22
Q

Diagnostic tests for iron

A
  • Serum ferritin (measure of iron stores)
  • Serum Fe
  • Serum transferrin
  • Transferrin saturation %
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23
Q

What is serum ferritin

A
  • Storage form of iron

- Low = iron deficient (high = iron overload or reactive)

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24
Q

serum iron

A

Labile in blood, so reflects recent intake of iron

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25
Q

What is serum transferrin

A
  • Carrier molecule for iron from gut to stores
  • Homeostatically goes up if iron is deficient
  • Reflects total iron binding capacity (TIBC) of the blood
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26
Q

TIBC

A
  • total iron binding capacity

- laboratory test that measures the blood’s capacity to bind iron with transferrin

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27
Q

% transferrin saturation

A
  • Sensitive measure of iron status
  • Reflects proportion of transferrin with iron bound
  • Low TF saturation indicates iron deficiency
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28
Q

What are the iron studies like in iron deficient anaemia

A
  • Serum iron: low
  • Serum transferrin/TIBC: high
  • % transferrin saturation: low
  • serum ferritin: low
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29
Q

What are the iron studies like in anaemia of chronic disease

A
  • Serum iron: low
  • Serum transferrin/TIBC: low
  • % transferrin saturation: normal
  • serum ferritin: normal or high
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30
Q

What causes microcytic anaemia

A
  • Iron deficiency

- Inherited disorders of haemoglobin (beta-thalassaemia trait)

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31
Q

What causes macrocytic anaemia

A
  • B12 and folate deficiency

- Myelodysplasia (causes defective erythropoiesis)

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32
Q

What causes normocytic anaemia

A
  • Anaemia of chronic disease
  • Acute haemorrhage
  • Renal failure (caused by low erythropoietin levels)
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33
Q

Anaemia of chronic disease

A
  • disease caused by chronic inflammation and seen in conditions such as connective tissue disease, malignancy, and chronic infection such as TB
  • functional deficiency of iron in the places that it’s required due to cytokines which impair the mobilization of iron from stores to cells where it’s needed in the bone marrow
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34
Q

haematinic deficiency

A

deficiency of any of the vitamins and minerals essential for normal erythropoiesis

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35
Q

what can RBCs look like in haematinic deficiency

A

microcytic/macrocytic
hypochromic
anisopoikilocytosis

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36
Q

Hypochromic

A

pale RBCs

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37
Q

anisopoikilocytosis

A

variation in size and shape of RBCs

38
Q

haemoglobinopathy

A

inherited blood disorders in which the individual has an abnormal form of haemoglobin or decreased production of haemoglobin

39
Q

What do RBCs look like in haemoglobinopathies

A

sickled

40
Q

Haemolysis

A

rupturing of RBCs

41
Q

Haemolytic anaemia

A

RBCs are destroyed faster than they are made

42
Q

what do RBCs look like in haemolytic anaemia

A

polychromasia

43
Q

polychromasia

A

large blueish RBCs

44
Q

Pencil cells

A

long thin RBCs

45
Q

Target cells

A

RBCs that look like a target with a bullseye in the middle

46
Q

Reticulocyte count indicates

A
  • Indicate rate of production of RBCs in the bone marrow

- Useful to monitor response to treatment

47
Q

What is the reticulocyte count in precursor deficiencies

A

low

48
Q

What is the reticulocyte count if the bone marrow has been infiltrated

A

low

49
Q

What is the reticulocyte count in chronic bleeding

A

high

50
Q

What is the reticulocyte in haemolysis

A

high

51
Q

dyspepsia

A

indigestion

52
Q

melena

A

black tarry faeces discoloured by presence of digested blood, usually reflects significant bleeding in upper GI tract

53
Q

menorrhagia

A

abnormally heavy bleeding on menstruation

54
Q

Celiac disease

A

autoimmune disease that occurs in genetically predisposed people where the ingestion of gluten leads to damage in the small intestine.

55
Q

Crohn’s disease

A

A type of inflammatory bowel disease

56
Q

What things do you need to ask about history when anaemia is suspected

A
  • GI Symptoms: Dyspepsia / Reflux, Change in bowel habit (?melaena), Weight loss?
  • Menstrual History ?menorrhagia
  • Bowel history ?coeliac / Crohn’s disease
  • Dietary history
  • Travel History
  • Ethnic Origin
  • Family History
57
Q

What is megaloblastic anaemia caused by

A

vitamin B12 or folate deficient anaemia

58
Q

What are the RBC appearance in megaloblastic anaemia

A
  • Macrocytic

- MCV > 100

59
Q

Appearance of WBCs in megaloblastic anaemia

A

hyper segmented neutrophils (more than 4 nuclear lobes)

60
Q

what is pernicious anaemia a result of a deficiency in

A

Vitamin B12

61
Q

Why is there B12 deficiency in pernicious anaemia

A
  • Gastric parietal cells are destroyed by autoimmune causes
  • Leads to a deficiency in intrinsic factor (as it’s secreted by parietal cells)
  • Intrinsic factor is required to bind to B12 to facilitate its absorption
  • Body can’t absorb B12 in the terminal ileum where intrinsic factor is located
62
Q

How is pernicious anaemia treated

A

with B12 injections (as it can’t be absorbed in the gut)

-load initially with 5 doses on alternate days and then once every 3 months

63
Q

What causes vitamin B12 deficiency

A

Dietary:

  • Strict vegans (B12 found in diary produce)
  • Supplement with oral B12

Malabsorption:

  • Coeliac disease and Crohn’s disease
  • Post gastric / ileal surgery
64
Q

Which drugs cause folate deficiency

A
  • Phenytoin

- Methotrexate

65
Q

What causes folate deficiency

A
  • Dietary – common
  • Malabsorption: Coeliac, Crohn’s disease
  • Excess Utilisation: Chronic haemolysis, Pregnancy
  • Alcohol
  • Drugs
66
Q

What causes anaemia of chronic disease

A
  • Chronic inflammation
  • Chronic infection e.g. TB
  • Auto-immune conditions e.g. rheumatoid arthritis
  • Cancer
  • Renal failure
67
Q

Characteristics of anaemia of chronic disease

A
  • Poor utilisation of iron in the body
  • Dysregulation of iron homeostasis
  • Impaired proliferation of erythroid progenitors
68
Q

What does poor utilization of iron in the body mean

A
  • Iron is stuck in macrophages of the reticuloendothelial system
  • There is poor mobilisation of the iron from the stores into the erythroblasts
69
Q

What happens in dysregulation of iron homeostasis

A
  • Decreased transferrin
  • Increased ferritin (acute phase reactant)
  • Increased hepcidin
70
Q

Hepcidin

A

protein that is a regulator of iron metabolism

71
Q

acute phase reactants

A

inflammation markers (proteins) that exhibit significant changes in serum concentration during inflammation

72
Q

What causes impaired proliferation of erythroid progenitors

A
  • blunted response to EPO

- iron is functionally unavailable

73
Q

What causes sickle cell anaemia

A

point mutation in the beta globin gene causing HbS

74
Q

Describe the blood cells in sickle cell anaemia

A
  • Increased turnover of red cells = survival approx 20 days due to haemolysis
  • Raised reticulocytes >10%
75
Q

How is sickle cell anaemia managed

A
  • analgesia
  • hydration
  • transfusion
76
Q

Describe a sickle cell crisis

A

-Triggered by low blood O2 level
-Vaso-occlusive due to sickling in the vessels
Causes ischaemia leading to pain, necrosis and -potential organ damage

77
Q

Sickle cell trait

A
  • heterozygous,
  • 50% HbS and 50% HbA
  • much lower risk of sickling and crisis
  • resistance to malaria infection
78
Q

Describe HbS

A
  • forms long filamentous strands
  • insoluble at low O2 tension
  • RBCs become inflexible + spiky leading to crisis
79
Q

Clinical features of thalassaemia

A
  • enlarged spleen, liver, and heart

- bones may be misshapen (frontal bossing)

80
Q

frontal bossing

A

prominent, protruding forehead

81
Q

What is thalassaemia

A
  • Insufficient production of normal Hb, imbalance of alpha and beta chains
  • Inherited autosomal recessive, either alpha or beta thalassaemia
82
Q

Full blood count characteristics of beta thalassaemia

A
  • Microcytic

- Hypochromic

83
Q

What is beta thalassaemia diagnosed by

A
  • Hb electrophoresis

- Blood film

84
Q

Electrophoresis

A

A laboratory technique used to separate DNA and RNA or protein molecules based on their size and electrical charge

85
Q

Beta thalassaemia major

A
  • homozygous
  • disease
  • requires life-long transfusions
86
Q

Beta thalassaemia minor

A
  • heterozygous
  • carrier
  • aka Beta-thal trait
  • clinically healthy
87
Q

How is bone marrow infiltration investigated

A

Bone marrow sample obtained from iliac crest:

  • aspirate film for morphology of cells
  • trephine biopsy for histological section
88
Q

trephine

A

a hole saw used in surgery to remove a circle of tissue or bone

89
Q

Management of chronic anaemia

A

Treat the underlying cause:
Iron supplementation (oral ferrous sulphate 3 months)
Folic acid (oral folate for 3 months)
B12 (load initially then injections every 3 months)

Erythropoietin (EPO) weekly sub-cut injections in patients receiving haemodialysis or with kidney failure

90
Q

What does long term transfusion cause

A
  • Iron overload (iron deposition in organs)
  • Allo-antibodies (to foreign red cells)
  • Therefore have to be careful

Module 103: The Heart, Lungs and Blood (51 decks)

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