Anaemia and B12 deficiency Flashcards
What is Autoimmune Hemolytic Anemia (AIHA)?
A condition where the immune system attacks and destroys the body’s own red blood cells.
What are the two types of AIHA?
‘Warm’ and ‘cold’ AIHA, classified based on the temperature at which the antibodies best cause hemolysis.
What is the most common type of AIHA?
Warm AIHA.
At what temperature does haemolysis occur best in Warm AIHA?
At body temperature.
What type of antibody is typically involved in Warm AIHA?
IgG.
Where does haemolysis typically occur in Warm AIHA?
Extravascular sites, such as the spleen.
What are some general features of haemolytic anaemia?
Anaemia, reticulocytosis, low haptoglobin, raised lactate dehydrogenase (LDH), and indirect bilirubin.
What are specific diagnostic features of AIHA?
Positive direct antiglobulin test (Coombs’ test).
What type of antibody is typically involved in Cold AIHA?
IgM.
At what temperature does haemolysis occur best in Cold AIHA?
At 4 degrees Celsius.
How is hemolysis mediated in Cold AIHA?
By complement and is more commonly intravascular.
What are some symptoms associated with Cold AIHA?
Symptoms of Raynaud’s and acrocyanosis.
What are common first-line treatments for Warm AIHA?
Steroids, potentially combined with rituximab.
Why do patients with Cold AIHA respond less well to steroids?
Because the hemolysis is complement-mediated and primarily intravascular.
What is a common autoimmune disease associated with Warm AIHA?
Systemic lupus erythematosus.
What is the significance of the direct antiglobulin test in diagnosing AIHA?
It detects antibodies attached to red blood cells, confirming immune-mediated hemolysis.
What are the main categories of hereditary haemolytic anaemias?
Hereditary haemolytic anaemias can be subdivided into membrane, metabolism, or haemoglobin defects.
What are the types of membrane defects causing hereditary haemolytic anaemia?
Hereditary spherocytosis and elliptocytosis.
What is a common metabolic defect causing hereditary haemolytic anaemia?
G6PD deficiency.
What are haemoglobinopathies?
Disorders like sickle cell disease and thalassaemia that affect the structure or production of haemoglobin.
How can acquired haemolytic anaemias be classified?
Into immune and non-immune causes.
What are the immune causes of acquired haemolytic anaemia?
Autoimmune (warm/cold antibody type), alloimmune (transfusion reaction, haemolytic disease of the newborn), and drug-induced.
What is autoimmune haemolytic anaemia?
An autoimmune disorder where antibodies target own red blood cells, can be warm or cold type.
What are examples of alloimmune haemolytic anaemia?
Transfusion reactions and haemolytic disease of the newborn.