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Year 5 path SW > Haematology 1: Haemolytic Anaemias > Flashcards

Haematology 1: Haemolytic Anaemias Flashcards

1
Q

What is the difference between intravascular and extravascular haemolysis ?

A

Intravascular- occurs inside the circulation
Extravascular- Occurs in the reticuloendothelial system

Inherited or acquired

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2
Q

Which one of these is an example of a disease in which you get extravascular haemolysis ?

A) Malaria
B) Hereditary spherocytosis
C) G6PD
D) Microangiopathic haemolytic anaemia

A

B- hereditary spherocytosis

Occurs in the spleen.
The others are all intravascular

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3
Q

Name one drug that causes intravascular haemolysis ?

A

Dapsone

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4
Q

What is the inheritance pattern of Hereditary spherocytosis ?

A

Autosomal dominant

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5
Q

What happens in haemolytic anaemia patients if they become infected with Parvovirus b19 ?

A

Transient aplastic crisis

Massive reduction in Hb and circulating RBCs. Low reticulocytes shows RBC production has stopped

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6
Q

What is the Name of the disease caused by Parvovirus b19 infection in children ?

A

Fifth’s disease

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7
Q

“Slapped cheeks” rash is characteristic of which infection in children ?

A

Parvovirus B19 (fifth’s disease)

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8
Q

What disease can immunocompromised patients get if they become infected with Parvovirus B19 ?

A

Pure red cell aplasia

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9
Q

Which stain can detect hepatic siderosis (iron overload)?

A

Perl’s stain (Prussian blue)

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10
Q

What are haptoglobins ?

A

A Protein in the blood that binds to and removes free haemoglobin

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11
Q

What causes Paroxysmal nocturnal haemoglobinuria ?

A

Acquired genetic defect in GPI (glycosylphosphatidylinositol) anchor - one way cells attach proteins to their surface

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12
Q

What does a low level or absent haptoglobin suggest ?

A

Intravascular haemolysis

All the haptoglobins have been used up and there is lots of free haemoglobin

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13
Q

Which of these proteins is not part of the red cell membrane ?

A)Spectrin
B)Ankyrin-1
C)Band 3
D) GPI
E) Myosin
A

E) Myosin

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14
Q

What is the diagnostic test for Hereditary spherocytosis ?

A

Osmotic Fragility test - increased sensitivity to lysis in hypotonic saline

also reduced binding to dye eosin-5-maleimide (flow cytometry)

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15
Q

Which autosomal recessive disease similar to hereditary eliptocytosis has abnormal sensitivity to heat?

A

Hereditary Pyropoikilocytosis

More severe

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16
Q

How is G6PD inherited ?

A

X-linked

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17
Q

List 6 triggers of acute haemolysis in patients with G6PD

A 
Antimalarials 
Dapsone
Fava beans 
Napthalene moth balls 
Infections
Antibiotics (Sulphonamides)

Normally G6PD patients are asymptomatic but these agents are oxidative and cause acute haemolysis

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18
Q

Name 2 characteristic cells seen in G6PD ?

A

Bite cells

Heinz bodies

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19
Q

Oxidative haemolysis causes characteristic Blue inclusions of denatured haemoglobin in RBCs. These are also known as ………………………

A

Heinz bodies

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20
Q

Name one type of cell that is characteristically seen in PKD (pyruvate kinase deficiency) ?

A

Burr cells (echinocytes)

They are spikey cells that look like sea urchins

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21
Q

List 4 causes of basophilic stippling ?

A

Pyrimidine 5 nucleotidase deficiency
Lead poisoning
Megaloblastic anaemia (alcoholics)
Thalassaemia

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22
Q

Which test is used to diagnose Paroxysmal nocturnal haemoglobinuria (PNH) ?

A

HAM’s test

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23
Q

Which test is used to diagnose Malaria ?

A

Thick and thin blood films

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24
Q

Which test is used to diagnose Autoimmune haemolytic anaemia ?

A

DAT test

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25
Q

Which type of immunoglobulin causes warm autoimmune haemolytic anaemia ?

A

IgG

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26
Q

Which type of immunoglobulin causes cold auto immune haemolytic anaemia ?

A

IgM

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27
Q

Child recovering from measles suddenly presents with haemoglobinuria after going into an ice bath. Complement levels are low. Donath-Landsteiner test is positive.

Most likely diagnosis ?

A

PCH (paroxysmal cold haemoglobinuria)

Preceding viral infection
Cold exposure
IgG antibodies bind to P-antigen on red cells
Causes complement mediated haemolysis on warming up again

28
Q

Which test can be used to diagnose Paroxysmal nocturnal haemoglobinuria ?

A

Ham’s test

Or immunophenotyping

29
Q

Which drug can be used to treat PNH?

A

Eculizumab

30
Q

Which antibodies cause TTP ?

A

Antibodies against ADAMTS13

(ADAMTS13 is an enzyme which normally cuts vWF into smaller strands of protein. In TTP, very long strands of vWF cause shearing of RBCs in vessels leading to haemolysis and schistocytes)

31
Q

What is the Pentad for TTP ?

A 
MAHA
Thrombocytopenia 
Renal impairment 
fever
Neurological symptoms
32
Q

Which infection is commonly responsible for causing HUS ?

A

E.Coli

33
Q

Which conditions are associated with cold AIHA ?

A

Think cold LID

Lymphoproliferative - CLL, Lympomas
Infections - Mycoplasma, EBV
Do not know - Idiopathic

34
Q

List 2 conditions associated with Spherocytes ?

A

Hereditary spherocytosis

Warm AIHA

35
Q

List 2 conditions and 1 drug that are associated with warm AIHA ?

A

CLL
SLE

Penicillin

36
Q

Name a congenital cause of aplastic anaemia ?

A

Fanconi anaemia

37
Q

List 4 drugs can cause aplastic anaemia ?

A

Carbamazepine
Chloramphenicol
Cytotoxic drugs
Phenytoin

38
Q

Name 1 drug used in the treatment of Sickle cell anaemia ?

A

Hydroxycarbamide

39
Q

Which drug acts to replenish vitamin b12 stores in pernicious anaemia ?

A

IV Hydroxocobalamine

40
Q

List 2 drugs that can cause Folate deficiency ?

A

Methotrexate

Phenytoin

41
Q

List causes of MAHA ?

A 
TTP
HUS
DIC
SLE
Malignant hypertension
Pre-eclampsia
42
Q

what is haemolysis

A

shortened RBC survival (<120 days)

43
Q

list causes of intravascular haemolysis

A 
malaria 
G6PD deficiency 
mismatched blood transfusion (ABO)
cold antibody haemolytic syndromes
drugs 
MAHA eg HUS 
TTP
paroxysmal nocturnal haemoglobinuria
44
Q

what is the most common cause of intravsacular haemolysis

A

malaria

G6PD offers some protection - common

45
Q

how can hereditary haemolytic anaemias be divided

A

disorders affecting:

  • membrane - cytoskeletal proteins, cation permeability
  • red cell metabolism - particularly glycolysis
  • haemoglobin - thalassaemia, sickle cell syndrome, unstable Hb variants
46
Q

list consequences of haemolytic anaemia

A

ANAEMIA
ERYTHROID HYPERPLASIA - increased RBC and reticulocyte production
INCREASED FOLATE DEMAND - give supplementation
SUSCEPTIBILITY TO PAROVIRUS B19 - infects erythroid cells in the BM - causes an aplastic crisis (dangerously low Hb) - ID a low reticulocyte count
PROPENSITY TO GALLSTONES esp with gilberts syndrome
INCREASED RISK OF IRON OVERLOAD
INCREASED RISK OF OSTEOPOROSIS

47
Q

what mutations cause gilberts syndrome

A

ugt1a1 ta7/ta7 genotype

48
Q

clinical features of haemolytic anaemia

A 
pallor
jaundice
splenomegaly 
pigmenturia
family history
49
Q

lab features of haemolytic anaemia

A 
anaemia 
increased reticulocytes
polychromasia
hyperbilibrubinaemia
increased LDH (esp in intravascular haemolysis)
reduced/absent haptoglobins
haemoglobinuria
haemosiderinuria
50
Q

features specific to intravascular haemolysis

A

LDH
reduced or absent haptogobins (removes free haemoglobin)
haemoglobinuria
haemosiderinaemia

51
Q

describe features of the RBC membrane

A

cytoskeletal scaffold make of spectrin
proteins link bilayer to the cytoskeleton - band 3
ankyrin-1 - absence = haemolytic anaemia
GPI - molecule lacking in paroxysmal nocturnal haemoglobinuria

52
Q

what are the defects in hereditary spherocytosis

A

vertical interaction (between proteins that link the lipid bilayer to the cytoskeleton)

band 3
protein 4.2
ankyrin
B spectrin

53
Q

what are the defects in hereditary elliptocytosis

A

horizontal interaction - mainly alpha and beta spectrin

alpha spectrin
beta spectrin
protein 4.1

54
Q

what is the most common defect of the red cell cytoplasm

A

hereditary spherocytosis

75% have FH (AD)

55
Q

appearance of hereditary spherocytosis on blood film

A 
cells lack area of central pallor 
smaller than normal 
dense staining 
increased MCHC
polychromatic cells (reticulocytes)
56
Q

appearance of hereditary elliptocytosis on blood film

A

no polychromastia
cells long shapes
blood count usually normal
not much haemolysis

57
Q

heredtary pyropoikilocytosis on blood film

A

homozygous form of hereditary eliptocytosis
fragment RBC
poikilocytosis (variation in shape)
can cause severe haemolytic anaemia

58
Q

describe features of G6PD deficiency

A

prevalent where malaria is endemic
x-linked
G6PD enzyme catalyses the first step in the pentose phosphate pw
generates NADPH which maintains intracellular glutathione (GSH)
GSH needed to protect cells against oxidative stress

59
Q

clinical effects of G6PD deficiency

A

neonatal jaundice
acute haemolysis
chronic haemolytic anaemia

60
Q

describe the blood film of a G6PD deficient patient during acute haemolysis

A

lots of contracted cells, nucleated red cells, bite cells, hemighosts, heinz bodies
in steady state, blood film usually normal

61
Q

list some key metabolic pathways in RBC

A 
embden- meyerhof - ATP, NADG 
hexose monophosphate shunt - NADPH 
rapoport-lueberig shuttle - 2,3-DPG 
nucleotide metabolism 
glutathione biosynthesis - GSH 
cytochrome b5 reductase - methemoglobin reduction
62
Q

features of pyruvate kinase deficiency on blood smear

A

most common defect in glycolytic pathway
lots of red cells have short projections - echinocytes
number of these cells increase post-splenectomy

63
Q

features of pyrimidine 5’- nucleotidase deficiency

A

defect of nucleotide metabolism

deficiency leads to basophilic stripping

64
Q

first line investigations for haemolysis

A

DAT - AI
Urinary haemosiderin /haemoglobin - IV haemolysis
Osmotic fragility - hereditary spherocytosis
G6PD +/- PK activity
Heinz body stain - oxidative haemolysis
Ham’s test/ glow cytometry of GPI-linked proteins - PNH
Thick and thin blood films - malaria

65
Q

management of haemolytic anaemias

A

folic acid
avoid precipitants
red cell transfer/exchange
immunisations against blood bourne viruses
monitor for chronic complications
cholecystectomy for symptomatic gallstones
splenectomy if indicated

66
Q

list indications for splenectomy

A

PK deficiency and some other enzymopathies
HS
thalassaemia syndromes
immune haemolytic anaemia
risk of overwhelming SEPSIS by encapsulated bacteria

67
Q

what is haemoglobin hammersmith

A

sever unstable haemoglobin variant that produces a heinz body haemolytic anaemia

Year 5 path SW (106 decks)

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