Haematology 5 - Haemolytic anaemias Flashcards
Recall some causes of intravascular vs extravascular haemolytic anaemias
Intravascular: - Malaria (black water fever) - G6PDD - MAHA (due to HUS/TTP/PNH) Extravascular: - Autoimmune - hereditary spherocytosis
Which infection are patients with haemolytic anaemias more susceptibile to?
Parvovirus B19
What is the expected LDH level in haemolytic anaemia?
High
What is the inheritance pattern of hereditary spherocytosis?
Autosomal dominant
How can hereditary spherocytosis be diagnosed?
Examination of mean cell fluorescence
Osmotic fragility test
What is the difference in clinical features of hereditary elliptocytosis in a heterozygote vs a homozygote?
Heterozygote: no polychromasia
Homozygote: Severe haemolytic anaemia (pyropoikilocytosis)
In which parts of the world is G6PDD most common?
Where malaria is endemic
What is the inheritance pattern of G6PDD?
X linked recessive
What is the normal physiological role of G6PD?
NADPH generation
What is the main symptom of G6PDD in neonates?
Jaundice
Recall 3 triggers for a crisis in G6PDD
Moth balls
Fava beans
Anti-malarials
What is the typical appearance of erythrocytes in Pyruvate Kinase Deficiency?
Kinocytes (‘spiky’)
What is the first investigation to do in haemolytic anaemia?
DAT/ Coombs test
Need to exclude autoimmune haemolysis
What does a positive urinary haemosiderin test show?
Intravascular haemolysis
What is homozygous hereditary elliptocytosis also known as?
Pyropoikilocytosis
Differentiate the class of immunoglobin involved in warm vs cold AIHA
Warm: IgG
Cold: IgM
What abnormal shape of RBC may be seen on blood film in warm AIHA?
Spherocytes
Recall and compare the management of warm vs cold AIHA
Warm: steroids, splenectomy, immunosuppression
Cold: treat underlying condition (lymphoma/EBV), avoid the cold, chlorambucil
What is paroxysmal cold haemoglobinuria?
Hb in the urine, usually caused by a viral infection
Which antibodies are the cause of paroxysmal cold haemoglobinuria?
Donath-Landsteiner antibodies
What is paroxysmal nocturnal haemoglobinuria?
Acquired loss of protective surface markers on RBCs leading to complement-mediated lysis and nocturnal intravascular haemolysis
Recall 2 symptoms of paroxysmal nocturnal haemoglobinuria
Morning haemoglobinuria
Throbosis
Recall 2 ways that paroxysmal nocturnal haemoglobinuria can be diagnosed?
- Altered GPI (surface proteins on RBC)
2. Ham’s test
What is the pathophysiology of autoimmune TTP?
Antibodies against ADAMST13 –> long strands of VWF
These VWF strands act like cheese wire in blood vessels
What is the classic pentad of symptoms in TTP?
MAHA Fever Renal impairment Neurological abnormalities Thrombocytopaenia
