red cells 2 Flashcards
what is anaemia
Hb below normal for age and sex
acquired anaemias are more common
how to determine normal range
subjects w/o disease
normal distribution
mean +/- 2SD
- excludes 5% of ‘normals’
- think about whether the level is normal for your patient
factors influencing reference intervals
age sex ethnic origin time of day sample taken e.g. cortisol levels time to analysis
Hb reference intervals
male 12-70: 140-180
male >70: 116-156
female 12-70: 120-160
female >70: 108-143
drops with age (physiological and increasing co-morbidities)
presentation of anaemia
general features due to reduced oxygen delivery to tissues;
- tiredness
- pallor
- SOB
- ankle swelling
- dizziness (esp on standing)
- chest pain
depends on age, speed of onset and Hb level
clinical features of anaemia related to underlying cause
evidence of bleeding
- menorrhagia
- dyspepsia, PR bleed
symptoms of malabsorption
- diarrhoea
- weight loss
jaundice
splenomegaly/lymphadenopathy
anaemia pathophysiology
red cell indices - what is it
automated measurement of red cell size and Hb content
can give a morphological description of anaemia and a clue to the cause
what is MCH
mean cell Hb
what is MCV
mean cell volume - size
morphological descriptions of anaemia
investigations for anaemia
use of discriminating test to guide further investigations
if lab is given adequate clinical info it will advise on further appropriate investigations
most common cause of hypochromic microcytic anaemia
investigations to check
iron deficiency
- measure serum ferritin
common causes of macrocytic anaemia and investigations to check
B12/folate deficiency
bone marrow disorders also - check if B12/folate are normal
investigation for normochromic normocytic anaemia
reticulocyte count to check red cell production levels
what type of anaemia is this
hypochromic, microcytic anaemia
red cells should be only slightly smaller than the lymphocyte
what is seen here
normal red cells
causes of low serum ferritin in hypochromic microcytic anaemia
iron deficiency
causes of normal/increased serum ferritin in hypochromic microcytic anaemia
- interpret w/ caution in someone who should be iron deficient
thalassaemia - normal iron stores but abnormal red cells
2y anaemia - cannot use iron in inflammatory condition for example
sideroblastic anaemia
- also increases in liver disease and in inflammatory processes but may not have iron bound
iron metabolism
total body iron
how are levels balanced
total body iron ~4g
dietary intake balanced by loss
most of the body’s iron is in Hb and is recycled
no pathway for excretion of XS iron
what happens to absorbed iron
bound to mucosal ferritin and sloughed off
OR
transported across the BM by ferroportin
then bound to transferrin in plasma
stored as ferritin -mainly in liver
role of hepcidin
synthesised in hepatocytes in response to increased iron levels and inflammation
blocks ferroportin so reduces intestinal iron absorption and mobilisation from reticuloendothelial cells
iron absorption in duodenum
Fe2+ > Fe3+
transported from enterocytes and macrophages by ferroportin
transported in plasma bound to transferrin
stored in cells as ferritin
where can haemolysis occur
can be extra or intravascular
what is seen here
immune haemolysis - mostly extravascular
spherocytes on film
agglutination in cold
AIHA
what is seen here
red cell fragments - schistocytes
seen in intravascular haemolysis
different types/causes of macrocytic anaemia
what class of anaemia is seen here
megaloblastic appearance
- oval macrocytes
- neutrophil hypersegmentation
