Anaemia Flashcards
What are general features of anaemia?
Tiredness/pallor Breathlessness Swelling ankles Dizziness Chest pain
What are the potential causes of anaemia (category)?
Bone marrow; cellularity, stroma, nutrients
Red cell; membrane, haemoglobin, enzymes
Destruction/loss; blood loss, haemolysis, hypersplenism
What is MCV?
Mean cell volume (cell size)
What is MCH?
Mean cell haemoglobin
What are the morphological descriptions of anaemia?
Hypochromic
Microcytic
Normochromic
Normocytic
Macrocytic
What do you test in hypochromic/microcytic anaemia?
Serum ferritin
What does serum ferritin tell you?
Low ; iron deficiency
Normal/Increased; thalassaemia, secondary anaemia, sideroblastic anaemia
What is the role of hepcidin?
Synthesised in hepatocytes in response to raised iron levels and inflammation
Block ferroportin so reduces intestinal iron aborption and mobilisation
What do you assess if normochromic normocytic anaemia?
Reticulocyte count
What does reticulocyte count tell you?
Increased; acute blood loss, haemolysis
normal/low; secondary anaemia, hypoplasia, marrow infiltration
What is secondary anaemia?
Anaemia of chronic disease
Describe haemolytic anaemia
Congenital;
- hereditary spherocytosis
- enzyme deficiency
- haemoglobinopathy
Acquired
- autoimmune haemolytic anaemia
- mechanical
- severe infection
What is the direct antiglobulin test?
AKA Coombs test
Detects antibody or complement on red cell membrane
Contains either anti-human IgG or anti-complement
Reagent binds to Ab on red cell surface and causes agglutination
When will DAGT be positive/negative?
Positive; immune mediated haemolytic anaemia
Negative; non-immune mediated haemolytic anaemia
What causes warm autoantibody immune haemolysis?
Autoimmune
Drugs
CLL
What causes cold autoantibody immune haemolysis?
CHAD
Infections
Lymphoma
What causs alloantibody immune haemolysis?
Transfusion reaction
How can you tell if a patient is haemolysis?
FBC, reticulocyte count, blood film
Serum bilirubin, LDH
Serum haptoglobin
How do you treat haemolytic anaemia?
Support marrow function; folic acid
Correct cause
Consider transfusion
what does a B12/folate assay tell you?
Megaloblastic; B12 deficiency, folate deficiency
Non-megaloblastic; myelodysplasia, marrow infiltration, drugs
Describe vitamin b12 absorption
B12 binds to intrinsic factor from parietal cells in stomach
B12-IF complex attaches to IF receptors in distal ileum
Vit B12 bound by transcobalamin II in portal circulation for transport
What can cause megaloblastic anaemia?
B12 deficiency
- pernicious anaemia
- gastric/ileal disease
Folate deficiency
- dietary
- increased requirments i.e. haemolysis
- GI pathology e.g coeliac disease
Describe pernicious anaemia
Commonest cause B12 deficiency western populations
Antibodies against; intrinsic factor, gastric parietal cells
Malabsorption dietary B12
How is megaloblastic anaemia treated?
Replace vitamin
B12 deficiney; B12 IM injection, loading dose then 3 monthly maintenance
Folate deficiency; oral folate replacement, ensure B12 normal if neuropathic symptoms
What are some causes of macrocytosis?
Alcohol Drugs Disordered liver function Hypothyroidism Myelodysplasia
What is normocytic anaemia?
Normal sized red blood cells but small number of them
What is microcytic anaemia?
Small red blood cells with low MCV
What is macrocytic anaemia?
Unusually large RBCs
What is hypochromic anaemia?
Where cells are paler than normal
What is normochromic anaemia?
Normal colour of cells but abnormal number
