Anaemia and Blood Groups Flashcards
What is the major determining factor of whether a person needs a transfusion after an acute drop in Hb?
How long that person can maintain a compensatory increase in HR
What are three causes of haemolysis that are external to the RBC?
Immune mediated
Mechanical
Infection
If you’re rhesis negative will you have anti-D antibodies?
Not unless you’re exposed to D antigen
On a molecular level, what differentiates someone who is blood group A from B from O?
The gene they possess determines whether A or B will be added to their H antigen, or neither added in the case of O.
What is the most common enzymatic cause of haemolysis? What is seen on blood film?
G6PD deficiency
Blister/bite cells, spherocytes
Macrocytic anaemia with decreased reticulocytes indicates what?
B12 or folate deficiency
Alcohol abuse
Cytotoxic agents
How do you test for immune mediated haemolysis?
DAT (Coomb’s test)
Thalassemia causes what type of anaemia?
Microcytic
What are some signs of increased destruction of RBCs?
Jaundice
Decreased Haptoglobins
Increased LDH
What are some major signs of anaemia?
Palor
Lethargy
Failure to thrive
Hypoxia
Ischaemia
Tachycardia
What is MCHC?
The ratio of MCH to MCV giving the mean Hb per unit of volume of the RBC cell
What is polychromasia? What does it indicate?
RBC has RNA therefore it has left the bone marrow prematurely
B12 deficiency causes which type of anaemia?
Macrocytic
In what scenario is rhesis status problematic?
When a negative mother has a positive child
Which blood group is the most rare?
AB ~3%
What happens if the wrong blood group is transfused?
Eg A blood group receiving B blood
Immediate catatrophic immune response that is generally fatal
(The recipients antibodies’ attacking the donated RBCs)
Which blood groups are most common?
A and O = ~30-40% each
What is dyserythropoiesis?
Dysfunctional RBCs
What does a bone marrow trephine give you over a bone marrow aspirate?
Cellular architecture
On which chromosome are the ABO genes located?
9
What percentage of Australians are rhesis positive?
98%
Macrocytic anaemia with increase reticulocytes is indicative of what?
Haemorrhage
Haemolysis
Response to Fe or B12 treatment
What is MCV?
Mean corpuscle volume - mean volume of RBCs
Liver disease causes which type of anaemia?
Macrocytic
What is polycythaemia?
Too many RBCs
What is a membrane cause of haemolysis? What is seen on blood film?
Hereditary spherocytosis
Spherocytes
What type of blood can O people receive?
Only O
What type of blood can A people receive?
A or O
What is the most common cause of microcytic anaemia?
Iron deficiency
What are some signs of increase production of RBCs?
Reticulocytes
Polychromasia
What is MCH?
The mean amount of Hb per RBC
What type of blood can AB people receive?
Anything
What are some Hb causes of haemolysis? What is seen on blood film?
Thalassemias
Sickle cell
Unstable Hb
Sickle cells
What are hypochromic RBCs?
RBCs without enough Hb
What rhesis status must be monitored in pregnant women?
Rhesis negative
What are some mechanical causes of haemolysis?
Sepsis with disseminated intravascular coagulation
Hardware implants
HUS
Which responses to steroid therapy, IgG or IgM mediated haemolysis?
IgG
What are inotropes?
Drugs that modulate the force of heart contraction
What is the pathogenesis of anaemia of chronic disease?
Cytokines produced in the chronically inflamed state; IL-1, IL-6 and TNF-alpha stimulate the liver to produce hepcidin (along with other protein, eg CRP)
Hepcidin inhibits to use of iron from stores causing insufficient haemoglobin to be made.
Folate deficiency causes which type of anaemia?
Macrocytic
How does the CVS respond to an acute drop in Hb?
Increase HR
How is anaemia measured?
Hb concentration
What is the equation for tissue oxygen delivery?
CO x Hb x %Satn x 1.34
How do you diagnosis Thalassemias?
Hb electrophoresis