Haematology Session 2 Flashcards
What is the definition of anaemia?
A haemoglobin concentration lower than the normal range.
What does normal range of Hb vary with?
- age
- sex
- ethnicity
Why should the main cause of anaemia be established?
Anaemia is a sign of an underlying issue which should be treated to resolve the anaemia.
What are the symptoms of anaemia related to and what are they?
- Shortness of breath
- Palpitations
- Headaches
- Angina
- Weakness and lethargy
- Confusion
Related to insufficient delivery of oxygen.
What are the signs of anaemia?
- Tachycardia
- Pallor
- Systolic murmur
- Hypotension
- Tachypnoea
What are common signs associated with iron deficiency anaemia?
- Kolionychia - spoon nails
- Angular stomatitis - inflamed mouth corners
What are common signs associated with vit. B12 deficiency?
Glossitis - depapillation and inflammation of tongue
What are signs associated with thalassaemia?
Abnormal facial bone development - now rarely seen as it is preventable with early diagnosis.
Why might anaemia develop (bone marrow)?
- Reduced/dysfunctional erythropoiesis (marrow may not respond to the hormone)
- Abnormal haem synthesis
- Abnormal globin chain synthesis
(Bone marrow not producing RBCs)
Why might anaemia develop (peripheral RBCs)?
- Abnormal structure (degraded)
- Abnormal metabolism (G6PDH deficiency - broken down too fast)
- Mechanical damage
- EXCESSIVE BLEEDING
Why might anaemia develop because of the reticuloendothelial system?
Increased removal/hyperactivity.
Describe the normal process of erythropoiesis. *
- Low blood oxygen detected by kidney pericytes: stimulates prodution of erythropoietin
- EPO binds to receptors on erythroblasts which stimulates RBC production.
- Increased no. of RBCs means that oxygen levels rise
- Negative feedback on production of EPO.
What can anaemia result from when the process of erythropoiesis goes wrong?
- Lack of response (eg. kidney stops making EPO due to disease)
- Marrow cannot respond to EPO (chemo, parvovirus)
- No space for haemopoietic cells if marrow infiltrated - cancer or myelofibrosis
- Anaemia of chronic disease: iron not functionally available to marrow to make cells
- Myelodysplastic syndromes: abnormal marrow cells reduce RBC and WBC making capacity.
What mutations can occur in genes that encode globin chain proteins?
- Alpha thalassaemia
- Beta thalassaemia
- Sickle cell anaemia
What can defects in the haem synthesis pathway cause?
Sideroblastic anaemia (body is not able to use the iron it has to make haemoglobin).
Why can insufficient iron in diet lead to anaemia?
Not enough iron available to make haem
What does anaemia of chronic disease cause?
Functional iron deficiency (not available for erythropoiesis)
What is an inherited cause of haemolytic anaemia?
HEREDITARY SPHEROCYTOSIS
- Poor interactions between membrane and cytoskeleton
- Cells less flexible
- Damaged when squeezing through capillary
- Removed by RES
What is an acquired cause of haemolytic anaemia?
MECHANICAL DAMAGE
- Shear stress: cells passing through a defective heart valve
- Disseminated Intravascular Coagulation: small clots developing throughout blood stream, depletes clotting factors
- Heat damage (burns)
What is a sign of haemolytic anaemia from damage to cells?*
Presence of schistocytes (residues of RBCs)
Why might anaemia develop due to pyruvate kinase deficiency?*
- Defective glycolytic pathway means that cells get deficient in ATP = haemolysis
- No mitochondria so only anaerobic
- Membranes will look abnormal
Why might anaemia develop due to glucose-6-phosphate dehydrogenase deficiency?
- Will limit amount of NADPH, which regenerates glutathione to protect from oxidative stress
- Causes lipid peroxidation and protein damage
- Protein damage leads to formation of Heinz bodies
What are Heinz bodies and how do they cause anaemia??
- Aggregates of crosslinked haemoglobin
- Red cells get recognised as defective and are removed by RES, causing anaemia
When can anaemia develop from acute blood loss?
- Injury
- Childbirth
- Surgery