Anaemias : Diagnosis and Classification Flashcards
What is anaemia down to?
- Failure of production of RBC
- Destruction of RBC
- Loss of RBC
The production of sufficient numbers of functional red blood cells is dependant on what 4 things ?
- Synthesis of haem
- Synthesis of globin chains and incorporate to form Hb
- Effective erythropoiesis
- Functional bone marrow environment
What can cause too little iron?
- Reduced absorption by the GIT
2. Using too much iron during erythropoiesis
What enhances the absorption of iron ?
Vitamin C
Where is iron absorbed and which iron is absorbed easier?
Across the GI epithelial cells Haem iron (animal sources) >>>> non haem iron
What packages iron and why is this needed ?
Ferritin
Free intracellular iron is toxic
A low ferritin level is indicative of what?
Iron deficiency
What are the 4 tests to assess the iron profile ?
- Serum iron
- Ferritin
- Transferrin
- Transferrin saturation
What type of anaemia is iron deficiency anaemia?
Microcytic (low MCV) , (Low MCH and Low MCHC) anaemia
Where are our genes for alpha globin?
Chromosome 16
Where are is our beta globin gene?
Chromosome 11
Give an example of quantitative anaemia.
Thalassaemia
Give an example of qualitative anaemia.
Sickle cell disease
What mutations fully and partially inhibit the synthesis of the beta globin in beta thalassemia?
Completely - B0 type mutations
Partially - B+ type mutations
What occurs due to a failure of B globin chain production ?
— It results in an imbalance between alpha and beta chains
— free alpha chains are highly unstable which causes intramedullary destruction of red cell precursors and ..
— shortened life span of red blood cells that make it into circulation (haemolysis)
What are patients with beta thalassemia major dependent upon?
Transfusions
What are the three types of beta thalassemia ?
Beta thalassemia major
Beta thalassemia intermedia
Beta thalassemia minor
What disease do you get if you inherit 3 bad alpha globin chains?
Hb H thalassemia
What forms Hb S?
A change in the B globin gene on chromosome 11 with a Glu going to a Val
What can cause low O2?
- Infection
- Acidosis
- Dehydration
- Vigorous exercise
- Surgery
What type of anaemia is sickle cell anaemia and what does this mean?
Haemolytic (cells are being destroyed quicker than they are being produced)
What are some acute complications of small vessel obstruction ?
- Painful crisis
- Acute chest syndrome
- Priapism
- Stroke
- Acute anaemia
- Aplastic crisis
- Multi-organ failure
- Acute cholecystitis
What are some chronic complications of small vessel obstruction?
- Nephropathy
- Chronic pain
- Pulmonary hypertension
- Retinopathy
- Neurological impairment
- Hyposplenism
What does your spleen part of ?
Immune response
What does a high reticulocyte count indicate ?
It tell us that our bone marrow is working incredibly hard to push out the red cells and this is usually in response to something
Numbers of reticulocytes are _____ in the bone marrow and _____ in the peripheral blood
High
Low
What are B12 and floaters essential in the formation of?
Purines and pyrimidines
Where do we get B12 and folate ?
Dietary intake
What binds to B12 in the stomach?
Specialised gastric parietal cells release intrinsic factor into the system and these binds the B12 within it
Where does B12 come from ?
Animal sources only
Where does absorption of B12 occur?
Distal small intestine
Where is erythropoietin found?
In the kidneys
What does erythropoietin cause?
- Activation of HIF
- Increases EPO gene transcription and translation
- Causes increase in RBC production
What would you expect from a mutation causing constitutive activation of HIF?
Stimulate EPO production causing and increase RBC production leading to polycythaemia
What does increased hepicidin affect ?
How our body is able to absorb iron across gut membrane
What can occur as a result inflammation malignancy is chronic conditions ?
- Increased hepicidin
- Relative decrease in erythropoiesis
- LEADS TO FAILURE IN RBC PRODUCTION
What does aplasia mean?
Inability to form a cell you are interested in
How is red cell aplasia marked?
Severe reticulocytopenia
What are the acquired causes of aplastic anaemia ?
- infection (parvovirus B19)
- drugs
- autoimmunity
- malignancy
What is the congenital cause of aplastic anaemia ?
Diamond blackfan anaemia
What can parvovirus B19 cause ?
A transient block in erythropoiesis
What can cause failure of the bone marrow environment ?
- infiltration by malignant cells
- infiltration disease
- immune destruction
- drug destruction
What does haemolytic anaemia describe ?
Any process in which there is increased breakdown or destruction of mature RBCs resulting in a shortened life span
What can indicate a breakdown in RBCs ?
- anaemia
- raised bilirubin
- raised LDH
- decreases haptoglobin
- increased reticulocytes
- positive Coombes test
- spherocytes, schistocytes
What is bilirubin?
The breakdown product of haem
When is LDH released ? (Lactate dehydrogenase)
RBCs are broken down
What else causes high LDH?
- malignancy
- other tissue damage
What causes unconjugated hyperbilirubinaemia?
- overproduction of bilirubin
- failure to conjugate bilirubin
What are congenital problems that cause haemolytic anaemia ?
- membrane problems
- enzyme production
- haemoglobin problems
What are the acquired causes of haemolytic anaemia ?
- mechanical
- immune
- drugs
- infection
- other
What enzyme problems can cause haemolytic anaemia ?
- G6PD deficiency
* Pyruvate Kinase deficiency
What are microcytic RBCs indicative of?
- iron deficiency
- thalassemia
What are macrocytic RBCs indicative of?
- B12 / folate deficiency
- alcohol / drugs
- haemolysis
- hypothyroidism
- bone marrow infiltration
- pregnancy
What problems can someone have with normocytic RBCs?
- acute bleeding
- anaemia chronic disease
- mixed aetiology
