Anaemia Flashcards
What are the parameters for anaemia in men and women?
When may these ranges be different?
Hb <130g/L in men
Hb <120g/L in women
In pregnancy, extremes of age, different labs
What are the three layers of a centrifuged blood sample and what is contained in each?
What are their relative %’s?
Plasma 55% (91% water) - plasma proteins - electrolytes - hormones - nutrients Buffy coat - platelets - white cells Red cells 45%
Describe the structure and function of erythrocytes
Biconcave –> deform easily
No nucleus –> more Hb
O2 and CO2 transport
What are the four types of haemoglobin?
What chains are they made up of?
What is their quantity in normal adult blood?
HbA, alpha x 2, beta x2, >95%
HbA2, alpha x2 delta x2, <3.5%
HbF, alpha x2, gamma x2, <1%
HbS, alpha x2, 2 beta x2 (sickle mutation), Pathological
How does the oxygen dissociation curve shift in relation to pH, temperature, CO2, 2,3DPG, Haemoglobin type
- low pH shifts curve right
- higher temperature shifts curve right
- high CO2 shifts curve right
- high 2,3DPG shirts curve right
- HbF is left shifted, HbS is right shifted, methaemoglobin is right shifted
Explain the impact of 2,3DPG on oxygen affinity
High levels of 2,3DPG reduces oxygen affinity.
When oxygen is released, the beta chains of Hb are pulled apart, allowing entry of 2,3DPG, This results in lower affinity of HB for oxygen and improved delivery for O2 to the tissues
What can anaemia be due to? x3
Lack of blood
Reduction in Hb
Reduction in red cells
Reduction in haematocrit
What is meant by ‘aneamia is relative’? Give an example
Hb concentration is dependent on plasma volume.
For example, in pregnancy plasma volume is increased so Hb concentration appears to be lowered but oxygen capacity has not changed
What’s in the full blood count?
Haemoglobin - haematocrit - red blood count - mean cell volume - mean cell haemoglobin White Blood Count (+differential) Platelet Count Reticulocyte Count
What are the symptoms of anaemia?
What are the signs of anaemia?
What do the clinical features depend on?
Symptoms
- fatigue, breathlessness, palpitations, audible pulse, angina
Signs
- pallor, tachycardia, bounding pulse, flow murmur, signs of heart failure
Depend on:
- Hb level, time taken to fall (adaptation), cause, concurrent changes (e.g. 2,3DPG), other organ reserve
What are the two classic signs on anaemia on inspection?
koilonychia - spooned fingernails
angular stomatitis - inflammed corners of mouth
How can anaemia be classified?
In terms of cause
- Reduced production
- Destruction
- Poor function
In terms of mean cell volume (MCV)
- microcytic
- normocytic
- macrocytic
List the causes of anaemia that result in reduced production
Deficiencies - iron: dietary, malabsorption, bleeding - B12 - folate Bone marrow pathology - aplastic anaemia - myelodysplasia - myeloma Displacement in bone marrow - leukaemia - other cancer - myelofibrosis Chronic disease - renal failure - myeloma - chronic inflammatory conditions
List the causes of anaemia that result in destruction of red cells
Haemolysis (increased reticulocytes)
- immune (destroyed in spleen)
- non-immune
Bleeding
List the causes of anaemia that result in poor function of red cells (mostly congenital, also haemolysis)
Membrane defect - hereditary spherocytes - hereditary elliptocytosis Haemoglobin defect - sickle cell anaemia - thalassaemia Enzyme defect - G6PD - pyruvate kinase deficiency
How is the parvo virus related to anaemia?
Childhood virus, usually incocuous
Affects those with congenital anaemias
Shits down bone marrow for 4-5 days
Patients cannot compensate so go into stress
What is aplastic anaemia?
Autoimmine disorder against production of all 3 blood counts
What is myelodysplasia?
Older age, wear and tear
Can be precancerous
Similar to barrels oesophagus
What is myeloma?
Cancer of plasma cells, look at IG cells
What is myelofibrosis?
Scarring in bone marrow
What is haemantic absorption the absorption of?
Where are they absorbed?
Absorption of B12, folate and iron
B12 absorbed in terminal ileum, requires IF from stomach parietal cells
Folate is absorbed in the duodenum and jejunum
Iron is absorbed in duodenum
What is hereditary spherocytosis?
What are some of the symptoms?
What is the treatment?
- Mutation in cytoskeleton proteins, spectrin and ankyrin,
- Autosomal dominant
- Symptoms of haemolysis: slenomegaly, increased bilirubin, increased reticulocyte
- Treatment: folic acid, splenectomy, rarely transfusion
If the red blood cells are small what are the two most likely causes? How can these be differentiated?
Iron deficiency = low blood cell count
Thallasemia = high blood cell count
What is thalassemia?
What is the treatment for major? What is a complication?
Alpha or beta global chain disorder
Major, intermedia or minor
Features of haemoylsis (increased reticulocytes, increased bilirubin, splenomegaly)
Treatment is transfusion, iron overload syndromes
Transfused at 6 months, given more than needed in order to turn off bone marrow
What is sickle cell anaemia?
Autosomal recessive
Glutamic acid –> valine at positive 6 of beta global gene
Deoxygenation –> polymerisation of Hb
Obstructed capillaries –> painful crises and end organ damage
Hyposplenism
Treatment includes exchange transfusion and hydroxycarbamide
What G6PD deficiency?
ATP required for membrane shape, ion exchange and reduce methaemoglobin to deoxyhaemoglobin
Mature red cells are unable to synthesise protein and have no mitochondria
ATP form anaerobic glycolysis
Red cells unable to manage oxidative stress s
Favism
X-linked
What are the clinical features of congenital anaemias?
What are the laboratory evidence of haemolysis?
jaundice
splenomegaly
anaemia
gallstones
anaemia, hyperbilirubinaemia, reticulocytosis, raised LDH, reduced haptoglobin, direct anti globulin test negative
Categorise the causes of anaemia a in terms of MCV
Microcytic - iron deficiecny - thalassaemia - chronic disease (less common) - sideroblastic anaemia Normocytic - acute bleeding - anaemia of chronic disease Macrocytic - B12/folate deficiency - haemolysis - durgs - myelofibrosis - alcohol excess and liver disease hypothyroidism, pregnancy
What are the basic investigations for anaemia?
Full history
Examination
Full blood count Ferritin, B12 and folate Biochemistry: liver and kidney function Haemolysis screen Immunoglobulins
