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Year 3 - Haematology > Red cells 1 + 2 (ALSO SEE TABLE) > Flashcards

Red cells 1 + 2 (ALSO SEE TABLE) Flashcards

1
Q

Discuss the derivation of normal ranges for a FBC - DONE

Outline pathophysiological or morphological approaches to the assessment of anaemia - DONE

Describe symptoms of anaemia - DONE

Discuss investigations for iron deficiency anaemia

A

Outline structure of Hb and the basis of the haemoglobinopathies and thalassaemias - DONE

Describe breakdown of Hb to bilirubin and discuss the value of direct and indirect bilirubin measurement

Outline the principle and uses of the direct antiglobulin test in assessing haemolysis

Causes of inherited anaemias in terms of MEMBRANES, ENZYMES or Hb - DONE

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2
Q

Define anaemia

A

Reduction in RBCs or their haemoglobin content

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3
Q

Substances required for RBC production

  • metals
  • vitamins
  • amino acids
  • hormones
A

Metals - iron mainly
Vitamins - B12, folate (both mainly)
Hormones - erythropoietin mainly

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4
Q

How is Hb broken down to bilirubin

A

By the reticuloendothelial system

  • blood filtered through spleen and old RBCs broken down
  • the haem component is processed in the liver into bilirubin
  • the globin component (protein component) is broken down to amino acids which are reused
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5
Q

Erythrocytes have 3 components

A

Membrane, which contains:
Enzymes
Haemoglobin

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6
Q

What 2 proteins forming a chain in the cytoskeleton are important for maintaining the shape of RBCs

A

A & B-spectrin

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7
Q

In congenital anaemias, genetic defects can be described of what 3 things

A

In red cell membrane
In metabolic pathways (Enzymes)
In haemoglobin

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8
Q

What enzyme is involved in the pentose phosphate shunt and what is its relevance to RBCs

A

G6PD (glucose-6-phosphate dehydrogenase)
-responsible for 1st step in the pentose phosphate pathway which is a pathway important in preventing RBCs from oxidative damage

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9
Q

Outline structure of Hb

A

Four polypeptide subunits

  • Each subunit is composed of a protein component (GLOBIN chains) associated with a non-protein component (HAEM)
  • 2 globin components are ALPHA chains and 2 are BETA chains
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10
Q

Where is the haem component in associated with the globin component

A

Globin chain wraps around the haem group in the centre

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11
Q

Binding affinity of oxygen to haemoglobin increased under what conditions (4)

A

Increased pH
Decreased [2,3-BPG]
Decreased temp
Decreased PCO2

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12
Q

Adult haemoglobin (HbA) composed of what globulin chains

A

2 alpha and 2 beta (

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13
Q

Foetal haemoglobin composed of what globulin chains

A

2 alpha and 2 gamma

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14
Q

Define haemoglobinopathy + 2 causes of it

A

Inherited abnormalities of haemoglobin synthesis

Reduced or absent globin chain production, e.g. THALASSAEMIA
Mutations leading to structurally abnormal globin chain, e.g. SICKLE CELL DISEASE (HbS), HbC, HbD etc

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15
Q

Sickle cell Hb composed of

A

Haem molecule and:
2 α chains
2 β (sickle) chains

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16
Q

Missing both of which globulin chain would be INCOMPATIBLE WITH LIFE + why

A

Alpha chains

-because no way of making foetal Hb if no alpha chains

17
Q

Homozygous alpha zero thalassaemia is the clinical diagnosis of someone with no alpha chains

What death linked condition does this cause in babies

A

Hydrops foetalis

18
Q

How normal ranges of a FBC are derived

A

Subjects without disease
Normal distribution
Mean +/- 2 standard deviations
Excludes 5% of “normals”

19
Q

Factors influencing normal ranges of a FBC

A

Age
Sex
Ethnic origin
Time of day sample was taken

20
Q

Reference ranges of

  • male Hb (12-70 & >70)
  • female Hb (12-70 + >70)
A

Male

  • 140-180g/l
  • 116-156

Female

  • 120-160
  • 108-143
21
Q

Symptoms/signs of anaemia in general

A

Fatigue
Dyspnoea
Dizzy
Chest pain

Pallor
Oedema

22
Q

Underlying causes of anaemia

A

Bleeding

  • menorrhagia
  • GI bleeding

Malabsorption

  • diarrhoea
  • weight loss

Jaundice

Splenomegaly

23
Q

Pathophysiological approach to assessing anaemia

-firstly consider defect in 3 ways

A

Defect of

  • bone marrow
  • RBC itself
  • destruction or loss
24
Q

Pathophysiological approach to assessing anaemia
-once you’ve considered the 3 ways of defect (BONE MARROW, RBC ITSELF, DESTRUCTION/LOSS), think of the problems that can arise from these areas

So in what ways can the above 3 things be affected?

A

Bone marrow

  • cellularity
  • stroma
  • nutrients

RBC

  • membrane
  • enzymes
  • Hb

Destruction/loss

  • blood loss
  • haemolysis
  • hyperpslenism
25
Q

What are the 2 red cell indices (measurement of red cell size + Hb content) that can give a morphological description of anaemia (and a clue to the cause)

A

MCH (mean cell Hb)

MCV (mean cell volume)

26
Q

Morphological approach to assessing anaemia

-what are the 3 morphological subtypes that can be derived from the red cell indices from a FBC (MCH & MCV)?

A

Hypochromic microcytic
-RBCs have low Hb & smaller + paler

Normochromic normocytic

Macrocytic
-large RBCs that carry less Hb; also when RBCs grow too big, there’s less of them

27
Q

Morphological approach to assessing anaemia
-once you’ve derived the morphological cause (HYPOCHROMIC MICROCYTIC, NORMOCHROMIC NORMOCYTIC OR MACROCYTIC), what tests would you do for each cause respectively to further investigate?

A

Hypochromic mcirocytic
-serum ferritin (as the cause is usually LOW IRON)

Normochromic normocytic

  • reticulocyte count (gives idea bone marrow function)
  • blood film

Macrocytic

  • B12/folate
  • bone marrow
28
Q

Majority of body’s iron is where

A

Bound to Hb

29
Q

Iron is stored where in body in what form

A

Ferritin in liver

30
Q

What does hepcidin do + what is it made by

A

Regulates iron transportation
-when there’s enough iron in the liver, it produces hepcidin which binds to ferroportin and blocks further iron absorption by stopping it from transporting iron into duodenum and stopping mobilisation of iron from reticuloendothelial cells

31
Q

What is the transporter proteins called that binds to iron and transport it from GI tract into live stores

A

Ferroportin

Year 3 - Haematology (6 decks)

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