anaemia Flashcards
what is the definition of anaemia?
- haemoglobin concentration falls below defined level (outside the normal range)
- g/L
what is the clinical consequence of anaemia?
-insufficient O2 delivery
what are the clinical causes of anaemia? 3
- decreased Hb content
- decreased red blood cells
- altered Hb does not carry sufficient O2
what are the normal ranges of Hb?
- children
- women
- pregnant woman
- men
- 110-160
- 115-165
- 110-160
- 130-180
why is men’s normal haemoglobin count higher than women’s?
testosterone is a contributing factor
what is haematocrit?
% of red blood cells after centrifugation
what is the number of red blood cells per litre of blood?
4 x 10^12/L
what does MCV, MCH and MCHC stand for?
- mean cell volume
- mean cell Hb
- mean cell Hb concentration
what are the symptoms of anaemia? 5
- lethargy/fatigue
- shortness of breath
- palpitations
- headache
- worse symptoms is acute onset e.g. for a bleed
what are the signs of anaemia? 5
- skin pallor
- pale conjunctiva
- tachypnoea
- tachycardia
- spoon shaped nails
what are the main causes of anaemia? 2
- problems of inadequate synthesis
- problems of blood loss or consumption
explain the how we can have inadequate synthesis of blood? 2
- deficiency of necessary components (iron, B12, folic acid)
-bone marrow dysfunction/infiltration
(myelodysplasia)
explain how we can have problems with blood loss of consumption? 2
- bleeding
- haemolytic (increased red cell destruction, shortened RBC lifespan)
how do we classify anaemia? 3
- size of red blood cell
- acute or chronic
- underlying aetiology
what is the most common type of anaemia?
iron deficiency (is not a diagnosis in itself and should prompt other investigations to establish the underlying cause)
how can iron deficiency be caused? 3
- bleeding
- nutritional deficiency
- increased requirements
how do we confirm an iron deficiency? 4
- with iron studies
- ferritin (measure of iron stores)
- serum Fe
- transferrin
- transferrin saturation
name 4 diagnostic tests for iron?
- serum ferritin
- serum iron
- serum transferrin
- % transferrin saturation
what does serum ferritin test show? 2
-storage form of iron
low=iron deficient
what does serum iron test show?
-labile in blood so reflects the recent intake of iron
what does the serum transferrin test show? 3
- carrier molecule for iron from gut to stores
- homeostatically goes up if iron is deficient
- reflects total iron binding capacity (TIBC) of the blood
what does the % transferrin saturation test show? 3
- sensitive measure of iron status
- reflects proportion of transferrin with iron bound
- low TF saturation indicates iron deficiency
how can bleeding cause iron deficiency? 3
- occult gastrointestinal blood loss (GI malignancy, GI peptic ulceration)
- menstrual
- renal tract
how can we have an iron deficiency of inadequate intake? 2
- dietary= vegan/vegetarian
- malabsorption= coeliac and crohn’s disease
how can we have an iron deficiency of increased requirements?
pregnancy
what is anaemia of chronic disease caused by?
chronic inflammation and is seen in conditions such as connective tissue disease, malignancy and chronic infection such as TB
what are the different sizes of red blood cells? 3
- microcytic (small)- caused by an iron deficiency , shows inherited disorders of Hb (beta-thalassaemia)
- macrocytic (large)- caused by a B12 and folate deficiency (needed for the synthesis of nucleotides), shows myelodysplasia (causes defective erythropoiesis)
- normocytic (normal)- show anaemia of chronic disease, acute haemorrhage or renal faliure
what does a blood film show? 4
- haematinic deficiency (microcytic/ macrocytic)
- haemoglobinopathy (sickled cells)
- haemolysis
- other abnormalities in white cells, platelets leukocytes
what is the lifespan of a red blood cell?
100-120
what does reticulocyte count show? 4
- newly produced red blood cells
- can be calculated on a blood film
- indicates the rate of production of RBC by the bone marrow (low if bone marrow is infiltrated or precursor deficiencies)
- helps monitor response to treatment
what is red blood cell production driven by?
-erythropoietin from the kidney
what would an iron deficient blood film show? 4
- hypochromia
- microcytosis
- pencil cells
- target cells
what history would we have to take when anaemia is suspected? 7
- GI symptoms
- menstrual history
- bowel history
- dietary history
- travel history
- ethnic origin
- family history
what is megaloblastic anaemia? 2
- caused by the deficiency of vitamin B12 and folate
- macrocytic red blood cells
- hypersegmented neutrophils (more than 4 nuclear lobes)
what type of anaemia shows B12 deficiency? 8
- pernicious anaemia
- autoimmune
- deficiency of intrinsic factor
- cannot absorb B12 in terminal ileum where IF receptor are located
- check for autoantibodies
- treat with B12 injections
- common in strict vegans (need oral B12)
- common in coeliac and crohn’s disease
how can someone have a folate deficiency? 5
- dietary
- malabsorption
- excess utilisation (haemolysis and pregnancy)
- alcohol
- drugs
what is the most common for of anaemia in hospitalised patients? 1 what causes this?8
-anaemia of chronic disease
- chronic inflammation
- chronic infection
- autoimmune conditions
- cancer
- renal failure
- poor utilisation of iron in the body (iron is stuck in the macrophages of the reticuloendothelial system) (there is poor mobilisation of the iron from the stores into the erythroblasts)
- dysregulation of iron haemostasis (decreased transferrin, increased ferritin, increased hepcidin)
- impaier proliferation of erythroid progenitors (iron is functionally unavailable)
what causes sickle cell anaemia? 5
- point mutation in the beta globin gene causing HbS (sickle Hb)
- increased turnover of red cells= survival approx 20 days due to haemolysis
- sickle cell crisis= triggered by low blood oxygen level, vaso-occlusive due sickling in the vessels causing ischaemia leading to pain
- manage with analgesics, hydration and transfusion
- red blood cells become sticky and inflexible
what causes thalassaemia? 2
clinical features? 3
two types of beta?
- insufficient production of normal Hb- imbalance of alpha and beta chains
- inherited autosomal recessive- either alpha or beta
- enlarged spleen, liver, and heart
- bones may misshapen
- (beta) look for microcytic cells and hypochromic cells
- beta-thal major (homo)=disease, requires long-life transfusions)
- beta-thal minor (hetero)= carrier- clinically healthy
what are the 3 types of bone marrow infiltration?
- leukaemia (non-specific symptoms, bone marrow failure)
- lymphoma (lymphadenopathy, weight loss)
- myeloma (anaemia, hypercalcaemia, renal failure, bone lesions)
how do we obtain an bone marrow sample? 2
- aspirate film for morphology of cells
- trephine biopsy for histological section
when do we transfuse during acute anaemia? 4
- acute> chronic
- be guided by symptoms rather than Hb levels
- can the patient make blood with haematinic therapy
- if not then transfuse for symptoms
how can you get anaemia from a chronic hemorrhage? 2
- haematemesis (vomiting blood)
- melaena (darkened stools)
how do we manage chronic anaemia? 3
- treat the underlying cause: iron supplementation, folic acid and B12
- erythropoietin weekly sub-cut injections in patients receiving haemodialysis or with kidney failure
- long term transfusion causes- iron overload (iron deposition in organs) allo-antibodies (to foreign red cells)
what is the worldwide impact of childhood anaemia? 5
- increased risk of morbidity in children
- impaired physical and cognitive development
- poor pregnancy outcome
- contributes to 20% of all maternal deaths
- reduced work productivity in adults
