Red cells (anaemia) 2 Flashcards
What is the normal haemoglobin range for a healthy:
a) female (12-70)
b) elderly female (>70)
c) male (12-70)
d) elderly male (>70)
a) female = 120-160
b) elderly female = 108-143
c) male = 140-180
d) elderly male = 116-156
What clinical features may be seen in patients who are anaemic - related to the underlying cause
Evidence of bleeding:
- menorrhagia
- dyspepsia, PR bleeding
Symptoms of malabsorption:
- diarrhoea
- weight loss
Jaundice
Splenomegaly
Lymphadenopathy
What are the 2 main red cell indices that are used for investigating anaemia?
What are the possible morphological descriptions from these indices?
Mean cell haemoglobin (MCH)
Mean cell volume (MCV)
1) Hypochromic microcytic
2) Normochromic normocytic
3) Macrocytic
The morphological description of anaemia (from MCH, MCV measurements) gives an indication of the probable cause of the anaemia - and dictates the next step of investigation
What is the (usual) next step of investigation for:
a) hypochromic microcytic
b) normochromic normocytic
c) macrocytic
a) hypochromic microcytic = serum ferritin
* iron deficiency anaemia most common cause of h.m. anaemia*
b) normochromic normocytic = reticulocyte count
* can be elevated (haemolysing causes) or depressed (aplastic anaemia etc)*
c) macrocytic = B12/folate, bone marrow
* B12 & folate deficiency most common cause of macrocytic*
Hypochromic microcytic anaemia is identified on a blood film, so you measure serum ferritin…
What would be indicated by a:
a) Low serum ferritin
b) normal / elevated
a) Low serum ferritin:
* = iron deficiency anaemia
b) Normal or elevated serum ferritin:
- Thalassaemia
- secondary anaemia
- sideroblastic anaemia (rare)
Note that ferritin is elevated with inflammation and in some liver diseases
On the topic of iron:
a) how much is in us?
b) where is iron utilized?
c) where is iron stored?
a) 4g
b) haemoglobin and myoglobin (muscles)
c) RBCs, reticuloendothelial macrophages, liver
In what formm is dietary iron absorbed most efficiently?
In the form of haem (ie from blood)
non-haem iron absorbed less effectively
so up you, vegetarians
go learn the metabolic pathway for iron - roles of ferroportin, transferrin, ferritin, hepcidin
What are the causes of iron deficiency anaemia?
Insufficient dietary intake (veggies n vegans)
Menstruation (mennorhagia)
Dyspepsia, GI bleeding
Malabsorption - coeliac disease, gastrectomy
Increased requirement (pregnancy, puberty)
How do you correct iron deficiency anaemia?
Correct the deficiency:
- oral iron - usually sufficient
- IV iron if intolerant to oral
- transfusion rarely indicated
Correct the cause:
- diet
- ulcer therapy
- gynae interventions
- surgery
Normochromic normocytic anaemia is identified and investigation of reticulocyte count is carried out
What causes would these results indicate:
a) Increased reticulocyte count
b) Normal or low reticulocyte count
a) increased reticulocyte count:
- acute blood loss
- haemolysis
b) Normal or low reticulocyte count:
- Secondary anaemia - eg renal impairment
- hypoplasia
- marrow infiltration
What is secondary anaemia?
What morphological appearances of RBCs are seen in secondary anaemias?
Anaemias secondary to chronic diseases
70% normochromic normocytic
30% hypochromic microcytic
Another cause of normochromic normocytic anaemia is (abnormal) haemolysis
How do the values for Haemoglobin and reticulocytes change in haemolytic anaemia and why?
Accellerated RBC destruction decreases Haemoglobin
Bone marrow compensation for this = High reticulocyte count
The overall level of Hg depends on balance between production and destruction
Haemolysis can happen extravascularly and intravascularly
Which is bad?
Extravascular haemolysis occurs normally - but is pathologically elevated in certain conditions
Intravascular haemolysis is pathological and shouldnt happen
In certain haemoglobinopathies it occurs - eg in sickle cell disease
free haemoglobin in the blood is toxic
What are some congenital causes of haemolytic anaemia?
Do these cause intravascular or extravascular haemolysis?
Hereditary spherocytosis (HS)
Enzyme deficiencies (eg G6PD)
Haemoglobinopathies (eg HbSS)
These all cause increased extravascular haemolysis but conditions like sickle cell disease (HbSS) and G6PD cause some intravascular haemolysis as well
On a blood film, what would be the appearance of RBCs seen with intravascular haemolysis?
Schistocytes
Fragmented RBCs sort of all mashed up
On a blood film, megaloblastic anaemia has effects on the morphology of other blood cells as well
Which other blood cells show a characteristically different appearance in megaloblastic anaemia?
Neutrophils - hypersegmented appearance
B12 and folate are essential for DNA synthesis in blood cells - so deficiencies will affect white cells too - esp neutrophils
To summarise - identify the investigations associated with each morphological appearance of red blood cells
