L03: Anaemia Flashcards
What is the definition of anaemia
A reduction in haemoglobin
What does the range for low haemoglobin depend on
Age Gender Pregnancy Altitude Different labs
What is in the blood
Plasma proteins Electrolytes Hormones Nutrients Platelets White cells Red cells
What are the cell features of red cells
Biconcave
No nucleus
What is the key role of red cells
Oxygen and carbon dioxide transport
Where does erthropoiesis take place
In the bone marrow
What happens during bleed
Erythropoiesis increases and sometimes reticulocytes can become releases (reticulocytosis)
What is haemoglobin made of
4 polpypeptide chain
1 haem for each polypeptide chain
How many oxygen molecules bind to haemoglobin
4
What are the types of haemoglobin
HbA
HbA2
HbF
HbS
What is affinity
The ability to hold onto oxygen
What does haemoglobin affinity depend on
Body area Ph Temperature Co2 2.3DPG Haemoglobin type
What are the symptoms of anaemia
Nausea
Breathlessness
Palpitations due to heart working harder to get oxygen round the body
Angina (heart pain)
What are the signs of anaemia
Pallor Tachycardia Bounding pulse Flow murmur Signs of heart failure Conjunctiva- pale inside of eye Koilonychia - spooning of nails Angular stomatitis - sores at the angle of the mouth
What are the 3 main causes of anaemia
1) reduced production
2) increased destruction
3) poor function of haemoglobin
Why is it not enough to to diagnose anaemia
Anaemia indicates an underlying disease
How can reduced production occur to give anaemia
Deficiency in:
iron : due to dilatory, malabsorption, chronic blood loss
B12 & folate: due to pernicious anaemia, increased alcohol, using too much B12& folate
Reduced production due to bone marrow:
Aplastic anaemia
Myeloma
Myelodysplasia
Displacement in bone marrow:
Leukaemia
Chronic disease:
Renal failure : due to lack of erythropoietin
Myeloma
Chronic inflammatory disease
How can destruction occurs to give anaemia
Haemolysis (break down of red blood cells) Large spleen (macrophages can take out red cells) Bleeding (lose red cells quickly)
How can you get poor function to give anaemia
Red blood cell membrane defect:
Hereditary spherocytosis
Haemoglobin defect:
Sickle cell anaemia
Thalassemia
Red blood cell enzyme defect:
G6DP defiency
Why is iron important in RBC
Essential for haemoglobin production
Why is folate and b12 important in RBC
Turns uracil into thymidine for dna building
What is hereditatory spherocytosis
A defect in the red blood cell cytoskeleton means the RBC cannot pass through narrow vessels. RBC becomes damages and therefore quickly removed by macrophages.
What is the shape of RBC in hereditary spherocytosis
Sphere instead of biconcave
What is thalassaemia
Defect in alpha or beta globin gene resulting in abnormal form of haemoglobin
What is sickle cell anaemia
Defect of hb beta globin gene which changes the shape of haemoglobin
What can sickle cell anaemia lead to
Obstructed capillaries leading to spleen damage
How do we investigate anaemia
Take full history Full blood count Blood film Ferritin, b12 and folate levels Liver and kidney functions Haemolysis screen
How do we use hb and mean cell volume (MCV) to diagnose anaemia
Low hb and low MCV= iron deficiency anaemia, thalassemia, sickle cell anaemia
Low hb and normal MCV- chronic disease, acute blood loss, bone marrow failure
Low hb and high MCV- B12& folate deficiency anaemia, alcohol, haemolytic anaemia
What is mcv
Mean cells volume i.e size of cell
Where does Vitamin b12 get absorbed in the body
Terminal ileum
What factor does vitamin b12 need to become absorbed in the terminal ileum
Intrinsic factor
Where are intrinsic factors made
In the stomach from the parietal cells
What can stop the production of intrinsic factor form the stomach
Pernicious anaemia
If we have enough pernicious anaemia and B12 from the diet what can stop the absorption
Crohn’s disease which affects the small intestine and stops absorption of vitamin B12
If the stomach and small intestine are working well what can another cause be to haver b12 deficiency
Vegan diet because B12 is in animal products
What are the sources of folate in the diet
Vegetables
Where is folate absorbed
Small intestine
Therefore what can stop the absorption of folate in the body
Small intestine disease such as coeliac disease
What are the causes of iron deficiency
Blood loss
A lack of iron in diet
Inability to absorb
Pregnancy
What does the blood loss in iron deficiency anaemia involve
Menstrual loss
Slow chronic loss such as peptic ulcer, cancer
Gastrointestinal bleeding
Where does iron get absorbed in the body if consumed in the diet
Small intestine so intestinal disorder can give iron deficiency
Or if small intestine as been bypassed or removed
What levels do we look at to confirm low iron
Ferritin levels
