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A3 ME3034 SPECIALTIES > W04 - HAEM: Blood; Transfusion; Blood Cells > Flashcards

W04 - HAEM: Blood; Transfusion; Blood Cells Flashcards

1
Q

Name the cells of the blood, describe their main functions and understand how they
are derived from stem cells

A

RBC
* erythroblast => reticulocyte -=> RBC dt EPO (kidney)

WBC (Buffy coat)
lymphocyte SC => lymphocyte
granulpcyte progenitor cell => other white cells
PLT. (Buffy coat) = prevention of leaks
* megakaryocyte

COAG. FACTORS (Plasma) = prevention of leaks, clots

ALBUMIN (Plasma)

ANTIBODIES (Plasma)

  • oxygen and co2 transported via rbcs
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2
Q

Know which hormones controlling blood cell production can be used therapeutically.

A
  • EPO
  • G-CSF
  • Thrombopoietin agonist
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3
Q

Know the constituents of the ‘full blood count’.

A

Hb
RBC
Platelets
WBC
Neutrophils
Lymph
- monocyte
- eosinophils
- basophils

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4
Q

Describe the main functions of plasma. Understand the main haematological tests.

A

*plasma transports nutrients, waste, messages
- coag
- albumin
- antibodiies

  • Clotting time = clotting factors and platelets
  • platelet and leucocyte function tests
  • Iron = ferritin
  • B12
  • Folate
  • Marrow aspirate, rephine biopsy
  • LN biopsy
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5
Q

Know the function of the spleen and causes of splenomegaly.

A

The spleen controls the level of white blood cells, red blood cells and platelets (small cells that form blood clots). It screens the blood and removes any old or damaged red blood cells.

*red cell breakdown dt dysfunction = splenomegaly
* pigment gallstones dt chronic hemolysis and increased bilirubin

CHICAGO
C – Cancer
H – Haematological malignancies – anaemia, leukaemia, lymphoma,
I – Infection (CMV, HEP, HIV, TB, parasitic (malaria)). EBV is the most common community acquired
Inflammation – sarcoid, amyloid
C – Congestion; portal hypertension
A – Autoimmune(RA, SLE)
G – Glycogen storage disorders
O – Other – amyloidosis, sarcoidosis

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6
Q

Myeloid vs Lymphoid

A

Myeloid progenitors give rise to red blood cells, granulocytes, monocytes, and platelets.

Lymphoid progenitors give rise to lymphocytes and NK cells

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7
Q

Significance of reticulocyte count

A

measure of red cell prod.

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8
Q

Know the main components of blood that can be transfused and their indications.

A

indications for rbc transfusion
1. acute severe anemia
2. improve QoL w/ anemia
3. Prepare pt for sx or speed up recovery
4. reverse dmg by own red cells

indications for PLT
1. massive haemorrhage
2. BM failure
3. sx prophylaxis
4. cardiopulmonary bypass

FFP
1. massive haemorrhage
2. DIC with bleeding
3. prophylax.

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9
Q

Understand why blood groups restrict how blood can be transfused.

A

a

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10
Q

Understand when to send samples to blood bank, the principles of what happens to
samples within the laboratory and when/how blood is made available.

A
  • group and screening
  • coombs test: detect the presence of antibodies against circulating red blood cells (RBCs) in the body, which then induce hemolysis
  • direct: auimm haemolytic anemia, passi e antiD
  • indirect: cross matching
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11
Q

Know the main hazards of blood transfusion.

A

initiating immune response

group a => Ab against B

B => Ab against A

O => Ab against A and B

AB = no Ab against A and B

  • RhD negative individuals can make anti-D if exposed to RhD+ cells
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12
Q

Understand the pathophysiology of haemolytic disease of the newborn and how it is
prevented.

A

*Transfusion or pregnancy
Anti-D can cause transfusion reactions or haemolytic disease of the newborn

  • anti-d sensitisation dt igG crossing placenta

> prophylactic anti-D, sensitising events
If you’re Rh negative and have not been sensitized, you’ll get a medicine called Rh immunoglobulin (RhoGAM)

+ similar process for NAIT

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13
Q

Be aware of future cellular therapies.

A

LEUCAPHERESIS
- bm harvests

OTHER BANKS
- bone, milk, tendons, heart valves, cells etc.

GENE THERAPIES

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14
Q

Outline pathophysiological or morphological approaches to the assessment of anaemia.

A

genetic defects may lead to congneital anemias
* red cell membrane: maintained by skeletal proteins
* metabolic pathways - enzyme ensure energy
* in haemoglobin
* haem synth defect

= haemolysis if red cell not viable

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15
Q

Describe the symptoms of anaemia.

A

General features due to reduced oxygen delivery to tissues:
Tiredness/pallor
Breathlessness
Swelling of ankles
Dizziness
Chest pain

Depend on age, speed of onset and Hb level

+J aundice
+ Splenomegaly/Lymphadenopathy

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16
Q

Discuss the appropriate investigations for iron deficiency anaemia.

A

1) DAGT - DIRECT ANTIGLOBULIN TEST: antihuman IgG, anti-complement; causes agglutination implying immune basis for haemolysis.
+ = imm mediated, - = non-imm med.

17
Q

Outline the structure of haemoglobin and the basis of the haemoglobinopathies and thalassaemias.

A
  • A1 and A2 chains, B1 and B2 chains
    + 4 Fe atoms
  • reduced/absent globin chain prod
    = THALASSAEMIA
  • mutations leading to abnormal chain
    = HbS = sickle cell
  • autosomal recessive inheritance
18
Q

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

A
  • red cell breakdown in reticuloendothelial system
  • macrophages in spleen, liver, LN, lungs
  • bilirubin bound to albumin in plasma
19
Q

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

A

The direct antiglobulin test (DAT) is a laboratory test that detects immunoglobulin and/or complement on the surface of red blood cells. The utility of the DAT is to sort hemolysis into an immune or nonimmune etiology

20
Q

Discuss the causes of inherited anaemias in terms of membranes, enzymes or
haemoglobin.

A

a

21
Q

hereditary spherocytosis

A

skeletal membrane protein dysfunction = spherical rbc

> folic acid
transfusion
splenectomy: severe anemia

22
Q

red cell enzymatic dysunfction

A
  • G6PD def. = commonest disease enzymopathy in the world, leading to vulnerability to oxidative dmg.
  • malarial protection
  • X-linked: affects males, female carriers
  • infective trigger to haemolysis, as well as acute illness, and drugs, and broad beans
  • blister/bite cells
23
Q

sickle cell disease

A

B chains have point mutation
* commonest inherited disorder
* autosomal recessive inheritance

= haemoglobin polymerisation, vaso-occlusion, endothelial dysfunction, sterile inflammation

  • painful vaso-occlusion
  • chest crisis, stroke
  • increased infection risk with hyposplenism
  • chronic hemolytic anemia: gallstone
  • sequestration crises. = ACUTE CHEST SYNDROME

> opiates for painful crises
hydration, oxygen
?abx

> vaccination, penicillin prophylaxis, folic acid
blood transfusion

24
Q

Thalassemia minor and major

A

Thalassemia mn. = commonest, carrier state
* hypochromic microcytic red cell indices

Beta thalassaemia mj = severe aneamia
* 3-6mos onwards
* ineffective BM expansion = bony deformities
+ splenomegaly
+ growth retardation

25
Q

Mgmt of B Thal. Mj.

A

> Chronic transfusion support, 4-6w
!iron overloading = early death in 2nd/3rd decade dt heart liver endocrine failure

> Iron chelation therapy
- s/c desferrioxamine infusion
- oral deferasirox

=> normal life expectancy with good adherence

> BM TRANSPLANTATION = CURATIVE

26
Q

Sideroblastic anemia

A

rare defect in haaem synth
| hereditary, commonest form of myelodysplasia

results in porphyrias

27
Q

Hb Normal Reference Values

A

MALE 12-70yo = 140-180
MALE >70yo = 116-156

FEMALE 12-70yo = 120-160
FEMALE >70yo = 108-143

28
Q

Significance of indirect bilirubin

A

sign of rbc breakdown (normal), creating unconjugated bilirubin

29
Q

Red cell indices

A

MCH = Mean cell haemoglobin
MCV = Mean cell volume (cell size)

-normochromic = hypo
- normocytic = hypo, macro

30
Q

Causes of Hypochromic and hypocytic

A
  • serum ferritin test

= Hypochromic microcytic anaemia
LOW FERRITIN = Fe Def.

NORMAL/INCREASED FERRITIN =
Thalassaemia
Secondary Anaemia
Sideroblastic anaemia

31
Q

Fe Metabolism

A

Iron absorbed in duodenum - Fe2+ > Fe3+
ferroportin transports from duo. to cells
transferrin transports from plasma to cells.
*FERRITIN WITHIN CELLS

*Hepcidin synthesised in hepatocytes in response to ↑iron levels and inflammation – blocks ferroportin

32
Q

Clinical signs & causes & mgmt of Fe Def.

A
  • hypochromic microcytic red cells
  • pencil/rod cell
  • koilonychia
  • atrophic tongue
  • angular chelitis

dt
- GI blood
- menorrhagia
- malabs: gastrectomy; coeliac

> oral fe, IV, transfusion
correct cause

33
Q

Normochromic normocytic anaemia

A

⇧reticulocyte count = acute blood loss, haemolysis

normal/⇩ reticulocyte count = 2º anemia, hypoplasia, marrow infiltration

2º anemia = chronic disease, inflammation = increased hepcidin

34
Q

Haemolytic anemia

A

Normochromic normocytic anaemia

*accelerated RBC destruction, compensated by BM
= ⇧retics.

35
Q

Haemolytic Anemia: Types & Mgmt

A

1) IMMUNE; extravasc.
* spherocytes

warm agglutination = auImm, drugs, CLL
cold agglutination = CHAD, infections, lymphoma
allo agglutination = transfusion reaction

2) NON-IMM; intravasc.
* red cell fragments, shistocytes

> folic acid supports marrow
correct cause
- immsuppr.
- remove site of rbc destr.
- sepsis, leaky valve, malignancy
?transfusion

36
Q

Macrocytic anemia

A

via B12/folate assay, blood film

megaloblastic = B12 def., folate def.
* pernicious anemia
* gastric/ileal disease; GI pathology
* dietary

non-megaloblastic = myelodysplasia, marrow infiltraation, drugs

37
Q

Megaloblastic anemia presentation and mgmt

A
  • lemon yellow tinge
  • bilirubin, LDH (rbc destruction & BM destruction)
  • red cell friable

> replace vitamin
B12 injection, loading dose then every 3mos.
Oral folate replacement

38
Q

Pernicious anemia

A

commonest cause of B12 def in west, AuImm.

Ab against IF (diagnostic), gastric parietal cells
= malabs of B12

A3 ME3034 SPECIALTIES (27 decks)

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