Haemotology Revision Flashcards
How are RBCs removed from circulation for degeneration?
By macrophages in the reticuloendothelial system.
What are the classic symptoms of anaemia?
Sob, tiredness, palpitations, headache, cardiac failure
What are signs of anaemia?
Pallor, tachycardia,tachypnoea, hypotension
What are some of the signs and symptoms specifically associated with the cause of anaemia
Iron deficiency = koilonychia and angular stomatitis
Vit B12 deficiency = glossitis
Thalassaemia = abnormal facial development
What is one of the key tests used to differentiate whether an anaemia is caused by inappropriate production or premature destruction?
Reticulocyte count
In bone marrow failure problems, what is the reticulocyte count like?
Low or inappropriately normal
What are reticulocytes?
Precursors or RBCs that are released by the bone marrow into circulation, still containing some RNA.
How do reticulocytes look on a blood film?
Stain slightly blue - polychromatic (lots of colours)
What is the MCV?
The mean cell volume of erythrocytes. Gives us information on their size - microcytic, normocytic, macrocytic
What are the common causes of macrocytic anaemia with a low reticulocyte count?
Low reticulocyte count so must be causing issues in the bone marrow Vitamin B12 deficiency Folate deficiency Myelodysplasia Liver disease Hypothyroidism Alcohol
What conditions can cause a normocytic anaemia with a low reticulocyte count?
Low reticulocyte count so must be due to an issue in the bone marrow
Primary bone marrow failure - aplastic anaemia, red cell aplasia
Secondary bone marrow failure - anaemia of chronic disease, combined haematinic deficiencies, uraemia, endocrine abnormalities, HIV infection
What conditions can cause microcytic anaemia with a low reticulocyte count?
TAILS Thalassaemia trait Anaemia of chronic disease Iron deficiency Lead poisoning Sideroblastic anaemia
What can be used as evidence of haemolysis?
Often macrocytic due to high reticulocyte count
High LDH - lactate dehydrogenase is released from lysed RBC
High bilirubin
What are the 3 main types of anaemia?
Acute blood loss
Splenic sequestration
Haemolysis
What is the difference between intravascular and extravascular haemolysis?
Intravascular haemolysis = RBCs breaking down within the blood vessels
extravascular haemolysis = RBC being coated with antibodies and are removed by the spleen or wider RES
What are the inherited causes of haemolytic anaemia?
Glycolysis defact - pyruvate kinase deficiency
Pentose p pathway - G6PDH deficiency
Membrane protein - hereditary spherocytosis
Haemoglobin defect - sickle cell
What are the acquired causes of haemolytic anaemia?
Mechanical damage - microangiopathic anaemia
Antibody damage - autoimmune haemolytic anaemia
Oxidant damage - exposure to chemicals or oxidants
Heat damage - severe burns
Enzymatic damage - snake venom
What are some of the main complications of prolonged haemolytic anaemia?
Pigment gallstones
Splenomegaly
What can cause mechanical damage to the RBCs?
Heart valves
Vasculitis
MAHA
DIC
What indication of pathology can be seen on the blood film of a patient with MAHA?
Schistiocytes
What is thalassaemia?
A reduced rate of synthesis of normal alpha or beta globin chains
What are the 2 main different types of autoimmune haemolytic anaemias?
Warm autoimmune haemolytic anaemia - IgG, maximally active at higher temperatures
Cold autoimmune haemolytic anaemia - IgM, maximally active at a lower temperature
What can cause autoimmune haemolytic anaemias?
Infections
Cancers of the lymphoid system
What is haematocrit?
The proportion of blood that is made up of RBCs
