Haematology Flashcards
What is the definition of anaemia?
Low concentration of haemoglobin
Give two signs of anaemia
Tachycardia
Dyspnoea
Pallor
Angina
What is the structure of haemoglobin A (HbA)?
4 Globular subunits
2 Alpha + 2 Beta
An Fe is bound to each subunit
How does foetal Hb differ from adult Hb in structure?
Foetal Hb has 2 Alpha and 2 Gamma subunits.
[vs. 2 Alpha and 2 Beta for adult]
True or false, adults have no foetal haemoglobin?
False. Around 2-4% of adult Hb is foetal Hb.
Give two causes of micro, normo and macrocytic anaemia
Micro: Thalassaemia, Iron deficiency, Chronic disease
Normo: Blood loss, Haemolysis.
Macro: B12/Folate deficiency, Alcohol.
Hypothyroidism is always macrocytic, true or false?
False. It can be normocytic or macrocytic.
In iron deficiency what happens to ferritin and transferrin levels? Which is the gold standard test?
Ferritin - Low
Transferrin - High
Ferritin is the best diagnostic test
True or false, infection or inflammation can cause Ferritin levels to increase
True
What inheritance pattern does Sickle Cell Disease follow?
Autosomal Recessive
Which species of malaria does Sickle Cell make people resistant to?
P falciparum
P vivax
What is the amino acid change caused by the SCD mutation?
A –> T
Glutamine –> Valine
[End up with TV]
Give an investigation you would perform to diagnose sickle cell disease?
Blood film
Reticulocyte count
FBC
Give two managements for acute sickle cell crisis
Analgesia (paracetamol/ibuprofen)
Oxygen
Foetal Hb
Fluids
Give two signs of Sickle Cell Disease
Priapism Frequent infection Anaemia (normocytic) Jaundice Visual loss Haematuria Splenomegaly
What is TACO?
Transfusion Associated Circulatory Overload
Acute dyspnoea, hypertension and oedema caused by blood transfusion.
What is the long term treatment for sickle cell disease?
Regular blood transfusions to keep sickle Hb <30%.
Hydroxyurea (reduces the frequency of crises)
What kind of anaemia does thalassaemia cause?
Microcytic
What inheritance pattern does Thalassaemia follow?
Autosomal Recessive
What investigations are done to diagnose thalassaemia?
FBC
Electrophoresis
What is the treatment for thalassaemia?
Blood transfusions +iron chelation to prevent TACO
Bone marrow transplant
True or false, thalassaemia provides some protection against malaria?
True.
Name two cell types of myeloid origin and two of lymphoid
Myeloid
- Basophils
- Eosinophils
- Monocytes
- Neutrophils
- Erythrocytes
- Megakaryocytes
Lymphoid (learned immunity)
- B/T lymphocytes
- NK cells
How big is a red blood cell?
5-10 microns in diameter
True or false, reticulocytes are smaller than mature red blood cells?
False. They are larger.
What is the life span of a red blood cell?
120 days
4 months.
What hormone stimulates the production of red blood cells? Where is it produced?
Erythropoietin (EPO)
Kidney in response to low O2 levels.
What deficiency is present in pernicious anaemia?
B12 + Folate (B9) deficiency caused by autoimmune destruction of parietal cells in the stomach which reduces levels of intrinsic factor, thereby reducing absorption of B12/9.
How do you treat pernicious anaemia?
B12 and B9 supplementation
[Must give them together as giving folate without B12 can cause degeneration of the spinal cord]
Where is unconjugated bilirubin conjugated and by what enzyme? What is the purpose of conjugation?
Liver (in the hepatocytes)
Uridine-diphosphoglucuronic glucuronosyltransferase (UDPGT aka UGT)
Converts it to glucoronic acid.
Purpose is to make bilirubin soluble in water so it can pass into bile.
Where is conjugated bilirubin converted into urobilinogen? What causes this conversion?
The small bowel.
Gut bacteria.
What does urobilinogen (produced in the gut) become?
80% –> Stercobilin (faeces)
2% –> Urobilin (urine)
18% –> Enterohepatic circulation
What is unconjugated bilirubin bound to in circulation?
Albumin
When unconjugated it is only lipid soluble not aqueous soluble.
What is Gilbert’s sydrome and what blood result would you expect?
Liver disorder affecting 5% of people. Involves dysfunction of UGT enzyme in hepatocytes.
This means bilirubin cannot be conjugated. So there is a high level of unconjugated bilirubin in the blood.
What are the terms for high and low platelets?
High:
- Thrombocytosis
- Thrombocythemia
Low:
- Thrombocytopenia
From which progenitor are platelets formed?
Megakaryocytes
What hormone stimulates the production of platelets? Where is it produced?
Thrombopoietin
Liver
[Liver damage can cause thrombocytopenia]
Give a cause of underproduction and of destruction of platelets
Underproduction:
- B12/Folate deficiency
- Liver failure (low thrombopoietin)
Destruction:
- Idiopathic thrombocytopenic purpura (ITP)
- Thrombotic Thrombocytopenic Purpura (TTP)
- Haemolytic Uraemic Syndrome (HUS)
- Systemic Lupus Erythemaotosus (SLE)
[Low platelets can also result from sequestration in the spleen]
What test is used to diagnose autoimmune haemolytic anaemia?
Coomb’s Test
IgG/M against RBC
In haemolytic anaemia what would you expect to happen to the levels of reticulocytes, spleen size, unconjugated bilirubin, and MCV?
Reticulocytes: Raised
Spleen: Enlarged
Unconj: Raised
MCV: Macrocytic
What is the treatment for immune/idiopathic thrombocytopenic purpura?
Prednisolone (1st line)
Rituximab (2nd line)
What is the pathophysiological cause of Thrombotic Thrombocytopenic Purpura?
Autoimmune inhibition of enzyme ADAMTS13 –> excessive Von Willebrand Factor (not broken down) which results in excessive clotting.
What is the treatment for Thrombotic Thrombocytopenic Purpura?
Plasma exchange
Immune Suppression
Which is more common type A or B haemophilia?
Type A is 5x more common.
What inheritance pattern does haemophilia follow?
X-linked recessive
Males affected, females carry
Which factors are affected in type A and B haemophilia?
A = 8 B = 9
Give two signs of haemophilia?
Bleeding/Bruising
Arthralgia/Arthropathy
Palsies (haematomas)
What is the treatment for haemophilia?
Blood transfusions
Clotting factors
Analgesia (not NSAIDs!)
Which clotting pathway is affected in haemophilia? Consequently what would you expect to happen to PT and aPTT and platelets?
Intrinsic pathway (12, 11, 9, 8)
aPTT prolonged
PT normal
Platelets normal
Which clotting factors are in the intrinsic clotting pathway? Which are in the extrinsic?
INT: 12, 11, 9, 8
EXT: 7