Haematology lectures Flashcards
What is haemopoiesis?
Formation of blood and immune cells
What is Erythropoiesis?
Formation of red blood cells
What stimulates Erythropoiesis?
Kidneys detect a drop in circulating oxygen and secrete the hormone erythropoietin
What is the WHO definition for anaemia (Hb levels)
Men: below 130g/L
Women: 120g/L
Pregnant: 110g/L
What are the main types of anaemia?
Iron Deficiency Anaemia; Anaemia of Chronic Disease; megaloblastic - folate or VitB12 deficiency
How is anaemia classified?
Microcytic
Normocytic
Macrocytic
What are the limits for normocytic anaemia?
80-99fL
What type of anaemia is macrocytic?
Megaloblastic anaemia
What type of anaemia is microcytic?
Iron deficiency anaemia; AoCD (can also be normocytic)
What are the general clinical features of anaemia?
Tiredness; Pale; Fainting; SOB; Increased HR; worsening angina, cardiac failure, leg cramping
What causes Iron Deficiency Anaemia?
Poor nutrition; malabsorption; blood loss; increased need for iron
Specific symptoms of IDA
Painless glossitis; Angular stomatitis; Koilonychia (spoon nails); Pica; Atrophic gastritis
First Line treatment for IDA
Ferrous sulphate, 100mg-200mg/day
Patient counselling for oral iron
Take on empty stomach; black stools; N&V, constipation, diarrhoea; interactions; dietary sources; importance of treatment
Oral iron absorption reduced by
Calcium, magnesium, bisphosphonates, tetracycline, PPI
How is IDA treatment assessed?
Hb should increase by 20g/L every 3-4 weeks. Check after 4 weeks, then every 3 months for 1 year
What is hepcidin?
Hepcidin causes ACD, and is produced in the liver to reduce iron absorption, prevent utilisation of available iron, and prevent release from iron stores
What is the mechanism of ACD?
Cytokine-mediated production of hepcidin, reduced production of erythropoietin
How can we differentiate IDA and ACD?
IDA: low serum iron and ferritin, normal or increased serum transferrin, increased serum transferrin receptors.
ACD: low serum iron, normal or increased ferritin, normal or decreased serum transferrin and receptor.
Summary: in ACD, the body thinks it has plenty of iron
When can erythropoietin analogues be used in ACD?
Chronic renal failure, cytotoxic chemotherapy, to increase yield of autologous blood in major surgery
What is megaloblastic anaemia?
Abnormality in haematopoietic cell maturation in the bone marrow leading to macrocytic RBCs
When should folate / VitB12 deficiency be suspected?
1+ of: Oval, macrocytic RBCs; hyper-segmented neutrophils; pancytopenia; unexplained neurological symptoms
What is pancytopenia?
Deficiency of RBS, WBC, and platelets
What causes folate deficiency?
Nutritional Deficiency
Malabsorption
Medication eg phenytoin
Increased requirement
How long does it take to replenish folate stores?
4 months
How is folate deficiency managed?
5-15mg folic acid daily for 4 months if due to diet, over 4 months if irreversible cause. Monitor FBC and reticulocytes after 10 days and 8 weeks. Exclude VitB12 deficiency before starting.
Folate deficiency prophylaxis
400mcg daily before pregnancy and for first 12 weeks, 5mg if established deficiency or previous neural tube defects.
What causes VitB12 deficiency
Dietary restriction (meat, diary, eggs, fish); Gastric abnormalities; small bowel disease; medication
How long can VitB12 stores last?
4 years
What is pernicious anaemia?
Autoimmune disorder causing reduced intrinsic factor needed for absorption in distal ileum
How is VitB12 deficiency without neurological involvement treated?
1mg IM hydroxocobalamin
1 injection 3x per week for 2 weeks, then one every 3 months. FBC and reticulocytes after 10 days and 8 weeks
How is VitB12 deficiency with neurological involvement treated?
1mg IM hydroxocobalamin
1 injection 5x per week for 4 weeks then once every 2 months. FBC and reticulocytes after 10 days and 8 weeks.
