Intro To Anaemia, Vit B12 And Folate Metabolism Flashcards
Give 4 specific signs associated with causes of anaemia.
- Koilonychia (spoon shaped nails) - iron defciency
- Angular stomatitis (inflammation of corners of the mouth) - iron deficiency
- Glossitis (inflammation and depapillation of tongue) - vit B12 deficiency
- Abnormal facial bone development (preventable with early diagnosis) - Thalassaemia (no or too little haemoglobin produced)
Give the 5 signs of anaemia
Pallor
Tachycardia (rapid HR)
Systolic flow murmur
Tachypnoea (rapid BR)
Hypotension
What is anaemia?
A haemoglobin concentration lower than the normal range
Give some symptoms of anaemia.
Shortness of breath
Palpitations
Headaches
Claudication (pain in limbs while exercising. Due to insufficient blood flow)
Angina
Weakness & lethargy
Confusion
Why might anaemia develop?
- Bone marrow problems - reduced or dysfunctional erythropoiesis; abnormal haem synthesis; abnormal globin chain synthesis.
- Peripheral RBC problems - abnormal structure; mechanical damage; abnormal metabolism.
- Excessive bleeding
- Removal - increased removal by RES
Describe inherited causes of anaemia.
Mutations in the genes -> faulty cytoskeleton. RBCs become less flexible and more easily damaged. Break up in circulation or removed more quickly by RES
Describe acquired damage anaemia.
- Mechanic damage e.g. shear stress as cells pass through defective heart valve; cells snagging on fibrin strands in small vessels where increased activation of clotting cascade has occured.
- Heat damage from severe burns.
- Osmotic damage (drowning in fresh water)
Why does G6PDH deficiency lead to anaemia?
Oxidative stress -> Heinz bodies -> removal by RES
What group of drugs can lead to anaemia (via GI bleeding)?
NSAIDs
What 2 key features can help work out the cause of an anaemia?
RBC size - macrocytic, microcytic, normocytic
Presence or absence of reticulocytosis
What is microcytic anaemia?
MCV smaller than normal
What is macrocytic anaemia?
MCV greater than normal
Give the types of macrocytic anaemias.
- Megaloblastic anaemias - interference with DNA synthesis during erythropoiesis, cell division delayed, erythroblastosis continue to grow to form megaloblasts; VERY LARGE IMMATURE NUCLEI e.g. vit B12 / folate deficiency
- Macronormoblastic erythropoiesis - normal relationship between development of nucleus and cytoplasm but erythroblasts larger than normal and give rise to larger red cells.
- Stress erythropoiesis - high reticulocyte count; high level of erythropoietin
Where in the body is folate stored?
Liver
What are the causes of folate deficiency?
Dietary deficiency
Increased requirements e.g. pregnancy, increased erythropoiesis, severe skin disease
Disease of duodenum and jejunum
Drugs which inhibit dihydrofolate reductase
Alcoholism
Urinary loss of folate in liver disease and heart failure
