Haematology Flashcards
What is normal adult haemoglobin made of?
2 alpha and 2 beta chains.
What is foetal haemoglobin made of?
2 alpha and 2 gamma chains.
What is haemoglobin S?
Haemoglobin S is a variant of Hb arising from a point mutation in the beta globin gene. The mutation leads to a single amino acid change, valine -> glutamine.
What organs are responsible for removal of RBC’s?
- Spleen.
- Liver.
- Bone marrow.
- Blood loss.
Give 5 causes of iron deficiency.
- Blood loss.
- Poor absorption.
- Decreased intake in diet.
- Hook worm!
- Breastfeeding, low iron in breast milk.
Give 3 symptoms of anaemia.
- Fatigue.
- Faintness.
- Breathlessness.
- Reduced exercise tolerance.
What hormone is responsible for regulating RBC production?
Erythropoietin.
What stimulates EPO?
Tissue hypoxia.
What is neutrophilia?
Too many neutrophils.
Where are platelets produced?
In the bone marrow. They are fragments of megakaryocytes.
What hormone regulates platelet production?
Thrombopoietin - produced mainly in the liver.
What is the lifespan of a a platelet?
7 - 10 days.
What organ is responsible for platelet removal?
The spleen.
What can cause platelet dysfunction.
- Reduced platelet number (thrombocyotpenia).
- Reduced platelet function.
Give 4 causes of bleeding.
- Trauma.
- Platelet deficiency e.g. thrombocytopenia.
- Platelet dysfunction e.g. aspirin induced.
- Vascular disorders.
Give 5 signs/symptoms of hypercalcaemia.
- Confusion.
- Bone pain.
- Constipation.
- Nausea.
- Abdominal pain.
What might you see in the ECG taken from someone with hypercalcaemia.
Shortened QT interval.
Hypercalcaemia = risk of MI.
What is the treatment for hypercalcaemia?
IV hydration and bisphosphonates.
What does rituximab target?
Targets CD20 on the surface of B.
What is the commonest cause of microcytic anaemia?
Iron deficiency.
What is the affect of sickle cell anaemia on reticulocyte count?
Reticulocyte count is raised.
Why is reticulocyte count raised in sickle cell anaemia?
Sickle cell disease is haemolytic, there is increased degradation of RBC’s. Production therefore increases in order to keep up with degradation and so reticulocyte count is raised.
What clotting factors depend on vitamin K?
2, 7, 9 and 10.
What kind of anaemia could methotrexate cause?
Macrocytic due to folate deficiency.
Give 4 causes of folate deficiency.
- Dietary.
- Malabsorption.
- Increased requirement e.g. in pregnancy.
- Folate antagonists e.g. methotrexate.
Give 3 things that can cause coagulation disorders.
- Vitamin K deficiency.
- Liver disease.
- Congenital e.g. haemophilia.
How does warfarin work?
It antagonises vitamin K and so you get a reduction in clotting factors 2, 7, 9 and 10.
How does heparin work?
It activates antithrombin which then inhibits thrombin and factor Xa.
Give 5 risk factors for DVT.
- Increasing age.
- Obesity.
- Pregnancy.
- OCP (hyper-coagulability).
- Major surgery.
- Immobility.
- Past DVT.
Give 3 symptoms of DVT.
Unilateral warm, tender, painful, swollen leg.
What forms the differential diagnosis for a DVT?
Cellulitis.
What investigations might you do in someone to see if they have a DVT?
- D-dimer in those patients with a low clinical probability.
- US compression.
What is the name of the score used to determine someones probability of having a DVT?
The Wells score.
The Wells score determines someones clinical probability of having a DVT. Give 3 factors the score takes into account.
- Active cancer.
- Recently bedridden or major surgery.
- Tenderness along deep venous system.
- Swollen leg/calf.
- Unilateral pitting oedema.
Describe the management for a DVT.
Aim of management is to prevent a PE!
- Anticoagulants e.g. warfarin/heparin.
Where would you normally take a bone marrow biopsy from?
Posterior iliac crest.
What is the most important medical treatment for DVT prophylaxis?
LMWH.
What is the difference between Raynaud’s disease and Raynaud’s phenomenon?
Raynaud’s disease is idiopathic.
Raynaud’s phenomenon can be due to SLE, scleroderma, RA, drugs e.g. beta blockers.
Describe the pathophysiological mechanism behind Raynaud’s disease.
Peripheral digital ischaemia due to intermittent spasm in arteries that supply the fingers/toes. Precipitated by cold/stress.
Describe the colour changes that are seen in Raynaud’s.
- Pale - due to vasoconstriction.
- Cyanotic - due to deoxygenation.
- Red - due to hyperaemia.
Describe the treatment for Raynaud’s disease.
- Physical protection.
- Vasodilators.
- Nifedipine (CCB).
- Stop smoking.
