L11 - Haemolytic Anaemias Flashcards
How long do red blood cells circulate for?
120 days
What is Haemolytic anaemia?
When red blood cell survival is shortened to 30-80 days
bone marrow tries to compensate by increasing production - can lead to reticulocytosis
if bone bone marrow cannot keep up then there is decrease in Hb
What are some clinical findings of Haemolysis?
- jaundice
- pallor
- fatigue
- splenomegaly
What are some chronic clinical findings of Haemolysis?
- gallstones
- leg ulcers
- folate deficiency
What are the 3 main classes of Anaemia and their types?
INHERITANCE
- Hereditary
- Acquired
SITE OF RBC DESTRUCTION:
- Intravascular
- Extravascular
ORIGIN OF RBC DAMAGE:
- Intrinsic
- Extrinsic
Describe some intrinsic causes of Haemolytic Anaemia and examples?
MEMBRANE DEFECTS:
- hereditary spherocytosis and elliptocystosis
ENZYME DEFECTS:
- PK deficiency
- G6PD
HAEMOGLOBIN DEFECTS:
- Sickle cell disease
- Thalassaemias
Describe some Extrinsic causes of Haemolytic Anaemia and examples?
IMMUNE:
1) Autoimmune
2) Alloimmune
NON-IMMUNE:
1) Red cell fragmentation
2) Drugs and chemicals
3) Hypersplenism
Decsribe the clinical features and management of hereditary spherocytosis?
FEATURES:
- Neonatal jaundice
- splenomegaly
- gallstones
- positive family history
MANAGEMENT: -Monitoring -folic acid -transfusion splenectomy
What is the HMP shunt and its role?
Hexose Monophosphate shunt
its role is to protect the red blood cell membrane and haemoglobin from oxidative stress.
What are the effects of Glucose 6 phosphate dehydrogenase deficiency?
leads to oxidative stress
- oxidation of Hb by oxidant radicals (denatured Hb)
- oxidised membrane proteins (reduced deformability)
What is Pyruvate kinase deficiency?
results in low ATP generation - needed to maintain red blood cell shape and deformability
needed to regulate intracellular cation concentration - in deficiency more K+ leaves and cell becomes dehydrated
What are the 2 globin disorders?
Thalassaemias - quantitative
defect in the rate of synthesis of alpha or beta globin chain - structurally normal
Variant hemoglobins - qualitative
production of structurally abnormal globin chains
What is the result of Thalassaemias and what are the different types?
imbalanced alpha and beta chain production - excess unpaired globin chains are unstable
leads to ineffective erythropoeisis
- hydrop foetalis
- Beta thalassaemia major
- thalasaemia intermedia
- thalasaemia minor
What are some clinical features of beta thalassaemia?
- severe anaemia
- bone marrow expansion (facial bone abnormalities)
- mild jaundice
- iron overload
- intermittent infections
What are the types of alpha thalassaemias?
Hb Barts Hydrops syndrome:
- deletion of all 4 globin genes
- incompatible with life
HbH disease:
- deletion of 3/4 genes
- common is SE asia
Thal Minor:
- deletion of 1 or 2 globin genes
- normal
