Interpreting Full blood count Flashcards
If you suspect a drop in Hb is due to fluids causing a dilutional effect what other full blood count element is useful and what would it show?
Look at the haematocrit, this shows the percentage of the total blood volume accounted for by red blood cells
What are the causes of macrocytic anaemia?
B12 and folate deficiency
Alcohol
What are the causes of normocytic anaemia?
Acute blood loss
haemolytic anaemia
Renal failure (decreased erythropoietin)
What are the causes of microcytic anaemia?
TAILS Thalassaemia Anaemia of chronic disease Iron deficiency Lead poisoning Sideroblastic anaemia
What are the causes of iron deficiency anaemia?
Chronic blood loss e.g. from GI tract malignancy/bleed
Increased demand e.g. pregnancy/growth
Decreased uptake e.g. coeliac disease, gastrectomy
Poor intake
What are the causes of B12 deficiency anaemia?
Pernicious anaemia e.g. no intrinsic fator to bind to b12 and allow it to be absorbed
malabsorption
Strict veganism
What are the causes of folate deciciency anaemia?
Dietary (alcoholism, neglect)
Increased demant e.g. pregnancy, growth
Decreased absorption e.g. coeliac, gastrectomy, pancreatic insufficiency
What should be treated first B12 or folate deficiency?
Treat in alphabetical order, B12 prevents subacute cord degeneration
What is the pathophysiology behind anaemia of chronic disease?
Inflammatory cytokines reduce the ability of the bone marrow to respond to erythropoetin
Also reduces cellular iron release so tranferrin saturation decreases
What are the causes of haemolytic anaemia?
Inherited: sickle, thalassaemia
Aquired: drug induced, autoimmune haemolytic anaemia
Disseminated intravascular coagulation
thrombotic thrombocytopenic purpura
What investigations should be done for haemolytic anaemia?
Blood film - schistocytes (microangiopathic haemolytic anaemias), inclusion bodies (malaria), spherocytes (hereditary spherocytosis)
What are the causes of polycythaemia?
Relative (decreased plasma volume):
-acute dehydration
-Chronic associated with obesity and hypertension
Absolute (increased RBCs)
-Primary - polycythaemia rubra vera
-Secondary - increased erythropeitin e.g. COPD, altitude
What investigations should be done if polycythaemia rubra vera is suspected?
Will be raised WCC and platelets
Request JAK 2 mutation testing and bone marrow biopsy
What are the causes of high and low lymphocyte counts?
High: -Viral infection -Chronic infection -Chronic lymphocytic leukaemia -Lymphomas Low: -Viral infection -HIV -Post chemo -Bone marrow failure (leukaemia/lymphoma)
What are the causes of high/low neutrophil counts?
High: -Bacterial infection -Inflammation -Necrosis -Corticosteroids -Malignancy -Chronic myeloid leukaemia Low: -Post chemo -Drugs (4C's Carbamezapine, Clozapine, carbimazole, colchicine) -Viral infection -Bone marrow failure
What are the causes of high/low monocytes?
High: -Some infections e.g. TB, malaria, typhoid -Autoimmune diseases -Leukaemias -Chronic inflammation Low: -Acute infections -Steroids -Post chemo
What are the causes of high eosinophil count?
Allergic reactions
Parasitic infections
Drug reactions
What are the causes of raised basophil count?
igE mediated hypersensitivity
Inflammatory disorders
Viral infection
CML
What are the causes of thrombocytopenia?
Decreased production: bone marrow infiltration, aplastic anaemia, myelosuppression
Increased destruction/consumption:
-Non-immune - DIC, TTP, haemolytic uraemic syndrome
-Primary immune - idiopathic thrombocytopenic purpura
-Secondary immune - SLE, chronic lymphocytic leukaemia
What investigations should be do for thrombocytopenia?
Blood film with bone marrow biopsy Infection sceen e.g. HIV, hep C LFTs lactate dehydrogenase - raised in haemolysis B12 and folate levels Coag screen if DIC suspected
What is the treatment of idiopathic thrombocytopenic purpura?
Observation
Corticosteroids
IV immunoglobulins
Platelet trasfusion if bleeding
When should platelet be given for thrombocytopenia?
When the platelets are less than 10x10^9 or less than 50x10^9 and bleeding
What are the causes of thrombocytosis?
Primary - essential thrombocythemia, myeloproliferative disorders
Secondary (reactive) - bleeding, inflammation, infection
What is the treatment of thrombocytosis?
Aspirin to prevent thrombus
Hydroxycarbamide (if primary cause)
What are the causes of pancytopenia?
bone marrow infiltration - leukaemia, myeloma, lymphoma, myelofibrosis
Myelosupression - drugs, chemo, lead, infection (HIV)
Impaired haematopoiesis - vit B12/folate deficiency, aplastic anaemia, myelodysplastic syndrome
Peripheral destruction of blood cells
