Haematology 5 - Haemolytic anaemias

Question 1

Recall some causes of intravascular vs extravascular haemolytic anaemias

Answer 1

Intravascular: 
- Malaria (black water fever) 
- G6PDD
- MAHA (due to HUS/TTP/PNH) 
Extravascular: 
- Autoimmune
- hereditary spherocytosis

Question 2

Which infection are patients with haemolytic anaemias more susceptibile to?

Answer 2

Parvovirus B19

Question 3

What is the expected LDH level in haemolytic anaemia?

Answer 3

High

Question 4

What is the inheritance pattern of hereditary spherocytosis?

Answer 4

Autosomal dominant

Question 5

How can hereditary spherocytosis be diagnosed?

Answer 5

Examination of mean cell fluorescence- Flow cytometry based EMA binding test

Osmotic fragility test

Question 6

What is the difference in clinical features of hereditary elliptocytosis in a heterozygote vs a homozygote?

Answer 6

Heterozygote: no polychromasia
Homozygote: Severe haemolytic anaemia (pyropoikilocytosis)

Question 7

In which parts of the world is G6PDD most common?

Answer 7

Where malaria is endemic

Question 8

What is the inheritance pattern of G6PDD?

Answer 8

X linked recessive

Question 9

What is the normal physiological role of G6PD?

Answer 9

NADPH generation

Question 10

What is the main symptom of G6PDD in neonates?

Answer 10

Jaundice

Question 11

Recall 3 triggers for a crisis in G6PDD

Answer 11

Moth balls
Fava beans
Anti-malarials

Question 12

What is the typical appearance of erythrocytes in Pyruvate Kinase Deficiency?

Answer 12

Kinocytes (‘spiky’)

also called Burr cells

Question 13

What is the first investigation to do in haemolytic anaemia?

Answer 13

DAT/ Coombs test

Need to exclude autoimmune haemolysis

Question 14

What does a positive urinary haemosiderin test show?

Answer 14

Intravascular haemolysis

Question 15

What is homozygous hereditary elliptocytosis also known as?

Answer 15

Pyropoikilocytosis

Question 16

Differentiate the class of immunoglobin involved in warm vs cold AIHA

Answer 16

Warm: IgG
Cold: IgM

Question 17

What abnormal shape of RBC may be seen on blood film in warm AIHA?

Answer 17

Spherocytes

Question 18

Recall and compare the management of warm vs cold AIHA

Answer 18

Warm: steroids, splenectomy, immunosuppression
Cold: treat underlying condition (lymphoma/EBV), avoid the cold, chlorambucil

Question 19

What is paroxysmal cold haemoglobinuria?

Answer 19

Hb in the urine, usually caused by a viral infection

causes intravascular haemolysis, as opposed to cold hemagglutinin disease

Question 20

Which antibodies are the cause of paroxysmal cold haemoglobinuria?

Answer 20

Donath-Landsteiner antibodies

Question 21

What is paroxysmal nocturnal haemoglobinuria?

Answer 21

Acquired loss of protective surface markers on RBCs leading to complement-mediated lysis and nocturnal intravascular haemolysis

Question 22

Recall 2 symptoms of paroxysmal nocturnal haemoglobinuria

Answer 22

Morning haemoglobinuria

Thrombosis

Question 23

Recall 2 ways that paroxysmal nocturnal haemoglobinuria can be diagnosed?

Answer 23

1. Altered GPI (surface proteins on RBC)- do flow cytometry
2. Ham’s test- red blood cells become more fragile when they are placed in mild acid

flow cytometry is the best diagnostic technique

Question 24

What is the pathophysiology of autoimmune TTP?

Answer 24

Antibodies against ADAMTS13 –> long strands of VWF

These VWF strands act like cheese wire in blood vessels

Question 25

What is the classic pentad of symptoms in TTP?

Answer 25

MAHA
Fever
Renal impairment
Neurological abnormalities
Thrombocytopaenia

Question 26

Blood film features of acute haemolysis

Answer 26

contracted cells
nucleated RBCs
Bite cells
Hemi-ghosts

Question 27

Blood film feature of oxidative haemolysis

Answer 27

Heinz Bodies (on methlyviolet stain)
Only seen transiently as quickly removed by spleen