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omgmbd > L12: Haemolytic Anaemias > Flashcards

L12: Haemolytic Anaemias Flashcards

1
Q

What is anaemia?

A

→reduced haemoglobin level for the age and gender of the individual

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2
Q

What is haemolytic anaemia?

A

→anaemia due to shortened RBC survival

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3
Q

What is the difference in Hb between neonates and infants?

A

→Hb is higher than in infants

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4
Q

How long do RBCs go without nuclei or cytoplasmic cells?

A

→120 days

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5
Q

What is the width of capillaries?

A

→3.5 microns
RBC are 8 microns - thus able to deform thanks to cytoplasmic enzymes, allowing them to go through small widths and thus survive for 120 days

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6
Q

How are senescent RBCs removed?

what happens to RBCs when they are old?

A

→Reticular endothelial system (RES) of the liver and spleen

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7
Q

Describe the characteristics of haemolysis

A

→Shortened RBC survival 30-80 days
→Compensation by Bone marrow to increase production
→Increased young cells in circulation = Reticulocytosis (increase in reticulocytes) +/- nucleated RBC seen in blood film
→RBC production unable to keep up with decreased RBC life span
→Decreased Hb

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8
Q

What is incomplete compensated haemolysis?

A

→RBC production unable to keep up with decreased RBC life span thus decreased HB

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9
Q

Why does reticulocytosis occur?

A

→due to reduced Hb
→the bone marrow may increase its output of red cells
→expanding the volume of active marrow

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10
Q

What are the clinical findings of haemolytic anaemia?

A

→Jaundice- increase in unconjugated bilirubin
→Pallor
→Fatigue
→Splenomegaly

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11
Q

What are the chronic clinical findings of haemolytic anaemia?

A

→Gallstones - pigment due to bilirubin
→Leg ulcers in lower leg- due to vasculastasis or local ischemia in the area
→Folate deficiency - due to increased use of folate to compensate for loss of RBC

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12
Q

What are the lab investigations for HA?

A

→Peripheral blood film

→ Bone marrow findings
→other findings

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13
Q

What are features of the lab investigations for HA (in peripheral blood film)? (what do you see in the blood film?)

A

→ polychromatophilia (much bigger and RBC basophilic in colour due to increased RNA content),
→ nucleated RBC,
→ thrombocytosis (increase in platelets)
→ neutrophilia with left shift (immature neutrophils)

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14
Q

What do morphological clues of HA lead to?

A

→underlying disorder

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15
Q

What are some morphological abnormalities of HA?

A

→Spherocytes,
→Sickle cell, Target cells,
→Schistocytes (fragmented, triangular rbc)
→acanthocytes

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16
Q

What are the bone marrow findings of HA?

compensatory mechanisms to haemolysis

A

→Erythroid hyperplasia of BM (excessive count of erythroid precursors - immature RBC) with:
→normoblastic reaction (increase in normoblasts)
→Reversal of Myeloid: Erythroid ratio (normally 2-5:1; HA as a result of erythroid hyperplasia: 1:4)

→Reticulocytosis (variable- depending on what stage of HA)

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17
Q

What are other findings of HA?

A

→Increased unconjugated bilirubin (due to increased RBC breakdown)
→Increased LDH (lactate dehydrogenase)
→Decreased serum haptoglobin protein that binds free Hb (increased Hb in plasma = increased binding to Hb because decreased serum haptoglobin protein and decreased Hb)
→Increased urobilinogen (due to bilirubin metabolism)
→Increased urinary hemosiderin

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18
Q

What is hemosidirin?

A

→brown iron-containing pigment usually derived from the disintegration of extravasated red blood cells

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19
Q

What are the different classifications of haemolytic anaemias?

A

→Inheritance
→Site of RBC destruction
→Origin of RBC damage

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20
Q

What are the inheritance classification of HA?

A

→hereditary eg Hereditary spherocytosis

→acquired eg Paroxysmal nocturnal haemoglobinuria, IHA

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21
Q

What are classifications of sites of RBC production in HA?

A

→intravascular eg Thrombotic thrombocytopenic purpura, haemolytic transfusion reaction
→ extravascular eg Autoimmune haemolysis

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22
Q

What are the classifications of origin of RBC damage in HA?

A

→Intrinsic (Intracorpuscular) -within RBC eg G6PD deficiency

→Extrinsic (Extracorpuscular) - outside RBC eg Delayed haemolytic transfusion reaction, Infections

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23
Q

What are some problems in intrinsic HA?

A

→Membrane defects e.g Hereditary Spherocytosis
→Enzyme defects e.g. G6PD; Pyruvate kinase deficiency
→Haemoglobin defects e.g. SCD; thalassaemias

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24
Q

What are some problems in immune-mediated HA?

A

→Autoimmune

→Alloimmune e.g. Haemolytic disease of newborn; haemolytic transfusion reaction

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25
Q

What things induce autoimmune HA?

A

→warm weather
→cold weather
→ drug induced

26
Q

What are some problems in extrinsic non- immune HA?

A

→Red cell fragmentation syndrome
→Mechanical trauma e.g. artificial valve
→Microangiopathic HA- caused by fibrin deposition in vascular endothelium
→Infections e.g. Malaria, clostridium
→March haemoglubinuria (hameolysis occurring between toes when marching)
→Hypersplenism

27
Q

What is involved in the management of HS?

A

→Monitor
→Folic acid
→Transfusion
→Splenectomy

28
Q

What are the observations in HS?

A

→microspherocytes-
→no central pallor,
→polychromatophilic-
→increased in RNA, no biconcave

29
Q

What are the observations in HE?

A

→elongated with no pointed ends

30
Q

What are the clinical features of HS?

A

→Asymptomatic until more severe haemolysis
→Neonatal jaundice
→Jaundice, splenomegaly, pigment gallstones
→*Reduced eosin-5-maleimide (EMA) binding – binds to band 3- flow cytometry
→Positive family history
→Negative direct antibody test
→Pigment gallstones

31
Q

What is used to test for HS?

A

→eosin-5′-maleimide (EMA) binding test is aflow cytometric test

32
Q

What is the role of Glucose-6-phosphate dehydrogenase?

A

→Role of the HMP shunt

33
Q

What is the role of the HMP shunt?

A

→Generates NADPH & reduced glutathione

→Protects the cell from oxidative stress

34
Q

What are the effects of HMP shunt deficiency?

A

→Oxidation of Hb by oxidant radicals
→Oxidised membrane proteins
reduced RBC deformability

35
Q

What does oxidation of Hb lead to?

A

→resulting denatured Hb aggregates & forms Heinz bodies – bind to membrane.

36
Q

What is the role of NADPH in the HMP shunt?

A

→converts oxidised glutathione to a reduced form- protects against oxidative stress that leads to haemolysis

37
Q

What are the morphological findings of oxidative haemolysis?

A

→bite cells,
→blister cells & Ghost cells;
→Heinz bodies

38
Q

What are bite cells?

A

→abnormally shaped mature red blood cell with one or more semicircular portions removed from the cell margin

39
Q

What are Heinz bodies?

A

→lumps of damaged hemoglobin attached to your red blood cells

40
Q

What should people with OH avoid?

A

→oxidative drugs like anti-malaria drugs

→ they have protection against malaria

41
Q

What is the genotype of OH?

A

→X-linked

42
Q

What is the genotype of PKD?

A

→Autosomal recessive

43
Q

What pathway is PK involved in?

A

→Glycolytic Pathway

→generate ATP

44
Q

What is thalassaemia?

A

→Defect in the rate of synthesis alpha- or beta-globin chain (structurally normal
→Excess unpaired globin chains are unstable

45
Q

What are the clinical divisions of thalassaemia?

A

→Hydrop foetalis
→β-Thalassaemia major
→Thalassaemia intermedia
→Thalassaemia minor

46
Q

What are the clinical features of beta thalassemia major?

A

→Severe anaemia

→Progressive hepatosplenomegaly

→Bone marrow expansion – facial bone abnormalities
→Transfusion dependent

→Mild jaundice

→Iron overload

→Intermittent infections, pallor

47
Q

What are the morphological features of beta thalassaemia?

A

→Microcytic hypochromic with decreased MCV, MCH, MCHC

→Anisopoikilocytosis; target cells, nucleated RBC, tear drop cells

→Reticulocytes >2%

48
Q

Why is the bone marrow expansion in beta thalassaemia?

A

→extensive erythroid hyperplasia

49
Q

What are the features of beta thalassaemia minor?

A

→Asymptomatic
→Often confused with Fe deficiency
→α-thal trait often by exclusion
→HbA2 increased in b-thal trait – (diagnostic)

50
Q

What are the features of Hb Barts hydrops syndrome of alpha thalassaemia?

A

→deletion of all 4 globin genes

→incompatible with life

51
Q

What are the features of HbH disease of alpha thalassemia?

A

→Deletion of 3/4 α-globin genes
→moderate chronic HA
Splenomegaly, hepatomegaly
→hypochromic microcytic, poikilocytosis, polychromasia, target cells

52
Q

What is the mutation in HbS?

A

→glutamic acid at position 6 → valine (HbS)

53
Q

What are the clinically significant sickling syndromes?

A

→HbSS
→HbSC
→HbS- β thalassaemia

54
Q

What are the diagnostic tests for SCA?

A

→Solubility test

→HLPC

55
Q

What is thalassaemia intermedia?

A

→transfusion independent
→diverse clinical phenotype
→Increased bilirubin level

56
Q

How many RBC produced a day and where?

A

2x10^11 RBC/day in the bone marrow

57
Q

What is compensated heamolysis?

A

When RBC production kept up with destruction of RBC thus Hb levels are normal

58
Q

What is jaundice?

A

Clinical finding in HA because increase in RBC breakdown - Hb broken down into Heme and global - heme further broken down into Fe and protoporphyrin - protoporphyrin broken in bilirubin (yellow pigment) thus increase in uncongugated protoporphyrin thus increase in bilirubin

59
Q

What is splenomegaly?

A

Enlargement of spleen due to increase in RBC destruction (occurs in liver and spleen)

60
Q

What is pallor?

A

Pale appearance due to decreased Hb

61
Q

normal vs abnormal RBC destruction

A

see slide

omgmbd (29 decks)

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