Acquired anaemias (Red cells 2) Flashcards
what is the normal range of RBC count in a male > 70 yrs?
116 - 156 g/L
what is the normal range of RBC in a female > 70 yrs?
108-143 g/L
what is the normal range of RBC in male and females of 12-70yrs ?
males: 140-180 g/L
females: 120-160 g/L
what are the general clinical features of anaemia?
tiredness pallor dyspnoea ankle oedema dizziness chest pain
what are the red cell indices and why are they helpful measurements?
automated measurement of red cell size and haemoglobin content
MCV - mean cell volume
MCH - mean cell haemoglobin
gives a morphological description of anaemia and a clue to the cause
when investigating a suspected anaemia, what 2 first line investigations would you carry out?
red cell indices (MCV and MCH)
blood film
if the red cell indices showed a normocytic, normochromic anaemia, what further investigation would you do next?
reticulocyte count
if MCV, MCH and blood film showed macrocytic RBC, what further investigations would you do next?
vitamin B12 and folate
bone marrow biopsy
if MCV, MCH and blood film showed hypochromic and microcytic, what further investigation would you do next?
serum ferritin
you are investigating the cause of a patients anaemia.
blood results show:
- microchromic microcytic anaemia
- ferritin = normal
thalassaemia
secondary anaemia
you are investigating the cause of a patients anaemia.
blood results show:
- microcytic hypochromic anaemia
- ferritin = low
what is the diagnosis?
iron deficiency anaemia
where is iron stored at ?
stored as ferritin in the liver
where is iron absorbed?
in the duodenum
how is iron transported in the plasma?
bound to transferrin
what is the role of hepcidin?
synthesised by hepatocytes in response to increasing iron levels. it blocks ferroportin so it reduces the absorption of iron from the intestines and mobilisation from reticuloendothelial cells
what are causes of iron deficiency anaemia?
GI blood loss menorrhagia malabsorption - gastrectomy - coeliac disease
what is the commonest cause of vitamin B12 deficiency in the western world?
pernicious anaemia
whats the aetiology of pernicious anaemia?
autoimmune condition where there is malabsorption of dietary vitamin B12 due to lack of intrinsic factor
(vitamin B12 is required to produce RBC therefore if deficient you don have enough to make RBC)
how can you diagnose pernicious anaemia?
presence of antibodies against intrinsic factor
via blood test
what is the treatment for pernicious anaemia?
vitamin B12 i/m injections
loading dose then 3 monthly injections
a patient presents with signs of anaemia so you perform a blood test. on the blood test it shows megaloblastic anaemia.
what are the differential diagnoses?
vitamin B12 deficiency
- pernicious anaemia
- gastric/ileal disease
folate deficiency
- dietary
- increased requirements - haemolysis
- GI pathology i.e. coeliac disease
alcohol drugs i.e. methotrexate disordered liver function hypothyroidism myelodysplasia
what acquired haemolytic anaemias are intravascular and extravascular?
immune = extravascular non-immune = intravascular
what test can you carry out to determine if the haemolytic anaemia is immune or not?
direct antiglobulin test (Coombs test)
you carry out a direct anti globulin test to determine if the haemolytic anaemia is immune or not.
what will the test show which will indicate that it is immune?
the reagent will bind to the Ab on the red cell surface and cause agglutination (clump together)
if it wasn’t immune then then RBC wouldn’t have the antibodies on their surface so wouldn’t react
in haemolytic anaemia, would the reticulocyte count be elevated or decreased?
elevated
in immune haemolysis, what are the aetiologies of warm, cold and alloantibodies?
warm;
- autoimmune
- drugs
- chronic lymphocytic leukaemia
cold;
- infections
- lymphoma
alloantibody;
- transfusion reaction
a patient involved in a car accident received a transfusion during the operation yesterday. when checking his blood later that day you notice that he is very pale and lethargic so you perform an FBC.
RBC is low but reticulocyte is high.
what is the cause of this abnormal blood levels?
haemolytic anaemia due to transfusion reaction.
where is vitamin B12 absorbed from and what is it absorbed by?
absorbed in the terminal ilium by intrinsic factor
what are causes of megaloblastic anaemia?
vitamin B12 deficiency
folate deficiency
what are the causes of acquired haemolytic anaemia?
immune
- autoimmune haemolytic anaemia
- drugs
- CLL
- CHAD - cold haemaglutinase disease
- Infections
- lymphoma
- transfusion reaction
non-immune;
- DIC
- pre eclampsia
- haemolytic uraemia syndrome (E.coli 0157)
- mechanical i.e. artificial valve
in haemolytic anaemia, would you expect the haptoglobin to be increased or decreased?
decreased
it is an acute phase reactant so will increase in repose to infection and inflammation
what is myelodysplasia?
rare blood cancer where the bone marrow isn’t producing enough cells
anaemia = MDS with single lineage dysplasia
cytopenia = MDS with multi lineage dysplasia
anaemia + excess blasts = MDS with excess blasts and increased risk of AML
a blood film shows a non-megaloblastic macrocytic anaemia.
what are the differentials?
myelodysplasia
marrow infiltration
drugs i.e. methotrexate
what drug can cause a non-megaloblastic macrocytic anaemia?
methotrexate
a blood film shows a normochromic normocytic anaemia with a normal reticulocyte count. what are the differentials?
secondary anaemia;
- renal disease (loss of production of erythropoeitin)
hypoplasia
marrow infiltration
what does a low haptoglobin level suggest?
haemolysis
A patient has a high LDH, high bilirubin and low hepatglobin levels. what do you suspect?
haemolytic anaemia
what test can be carried out to determine the cause of the haemolysis?
Coombs test - antiglobulin test
what does a positive coombs test indicate?
immune haemolysis
