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Flashcards in Haemolysis Deck (12):
1

What is haemolysis

Shortened survival of circulation red blood cells

2

What is the haemolysis screen?

Reticulocytes - INCREASED
LDH - INCREASED
Haptoglobin - REDUCED
Bilirubin - INCREASED

3

Causes of intravascular haemolysis

Low low haptoglobin
Positive urinary hemosiderin

RBC fragmentation - TTP, HUS and aHUS, DIC, direct damage
Paroxysmal Nocturnal Haematuria
Paroxysmal Cold Haemoglobinuria

4

Causes of extravascular haemolysis

Low haptoglobin

Immune mediated - Warm and cold AIHA
RBC membrane disorders
RBC enzyme disorders
Metabolic defects
Bacterial and parasitic infections

5

Paroxysmal noctural haemoglobinuria

Mutation in pig-A gene

--> defective production of phosphatidylinositol glycan A which is essential for the formation of the GPI anchor

--> loss of surface proteins which protect the cell from complement mediated lysis - CD55 and CD59

Results in haematuria and haemosiderinuria
Associated with aplastic anaemia
Morbidity from thrombosis

Treatment =
Eculizumab
Transfusions and thrombosis management

6

Paroxysmal Cold haemoglobinuria

Formation of a biphasic IgG anti-P antibody

--> Binds to RBCs at low temperature and upon warming --> complement mediated lysis

Causes:
- Idiopathic
- Syphilis
- Viral infections

Treatment = cold avoidence and supportive care

7

Causes of Warm Autoimmune haemolytic anaemia

Antibodies which react with RBCs at 37 degress

IgG and C3d --> uptake by macrophages

Causes:
- Idiopathic
- SLE
- CLL/lymphoma
- HCV
- CMV
- Methydopa
- EVANS syndrome - AIHA + ITP

8

Diagnosis of warm AIHA

Anaemia + Haemolysis + spherocyte + splenomegaly

DAT postive - IgG or C3d

Treatment =
- prednisone
- Intragam
- Splenectomy and vaccination
- AZA
- Rituxumab
- Folate supps

9

Cold AIHA

Antibodies which react with RBCs <37 degrees

C3d only

Secondary disease:
- MGUS and lymphproliferative disease
- EBV
- Mycoplasma
- SLE

Treatment:
- cold avoidence
- Rituximab

10

RBC membrane defects

Hereditary spherocytosis
- loss of vertical interactions
- ankyrin, spectrin, band 3
- flow cytometry = EMA binding

Hereditary ellipocytosis
- Loss of horizontal interactions

Ovalocytosis

11

Pyruvate kinase deficiency

Glycolytic pathway

--> reduced ATP --> RBC rigidity

--> Chronic haemolysis

Rare disorder

12

G6PD Deficiency

Glucose-6-Phosphate dehydrogenase deficiency

G6PD --> produces NADPH during times of oxidative stress --> reduces glutathione which scavenges ROS

Deficiency --> acute haemolytic crisis during oxidative stress

X linked disorder

Precipitants =
- Acute illness
- Anti-malarials
- Sulfur drugs
- Aspirin
- Naphthalene
- Fava beans

Treatment - stop precipitant, IV fluids, transfuse