Anaemia - covered in GI Flashcards
(55 cards)
What is autoimmune haemolytic anaemia (AIHA)?
AIHA may be divided into ‘warm’ and ‘cold’ types, based on the temperature at which antibodies cause haemolysis. It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection, or drugs.
What are the general features of haemolytic anaemia?
General features include anaemia, reticulocytosis, low haptoglobin, raised lactate dehydrogenase (LDH) and indirect bilirubin, and blood film showing spherocytes and reticulocytes.
What are the specific features of autoimmune haemolytic anaemia?
Specific features include a positive direct antiglobulin test (Coombs’ test).
What is warm AIHA?
Warm AIHA is the most common type, where the antibody (usually IgG) causes haemolysis best at body temperature, typically occurring in extravascular sites like the spleen.
What are the causes of warm AIHA?
Causes include idiopathic origins, autoimmune diseases (e.g., systemic lupus erythematosus), neoplasia, lymphoma, chronic lymphocytic leukaemia, and certain drugs (e.g., methyldopa).
What is the management for warm AIHA?
Management includes treating any underlying disorder and using steroids (+/- rituximab) as first-line treatment.
What is cold AIHA?
In cold AIHA, the antibody is usually IgM and causes haemolysis best at 4 deg C, mediated by complement and more commonly intravascular.
What are the causes of cold AIHA?
Causes include neoplasia (e.g., lymphoma) and infections (e.g., mycoplasma, EBV).
What are the subcategories of hereditary haemolytic anaemias?
Hereditary haemolytic anaemias can be subdivided into membrane, metabolism, or haemoglobin defects.
What are the hereditary causes of haemolytic anaemias related to membrane defects?
Hereditary spherocytosis and elliptocytosis.
What is a hereditary cause of haemolytic anaemia related to metabolism?
G6PD deficiency.
What are the haemoglobinopathies associated with hereditary haemolytic anaemias?
Sickle cell disease and thalassaemia.
What are the subcategories of acquired haemolytic anaemias?
Acquired haemolytic anaemias can be subdivided into immune and non-immune causes.
What are the immune causes of acquired haemolytic anaemias?
Autoimmune (warm/cold antibody type), alloimmune (transfusion reaction, haemolytic disease of the newborn), and drug-related (methyldopa, penicillin).
What are the non-immune causes of acquired haemolytic anaemias?
Microangiopathic haemolytic anaemia (MAHA), prosthetic heart valves, paroxysmal nocturnal haemoglobinuria, infections (malaria), drug-related (dapsone), and Zieve syndrome.
What is Zieve syndrome?
A rare clinical syndrome of Coombs-negative haemolysis, cholestatic jaundice, and transient hyperlipidaemia associated with heavy alcohol use, typically following a binge.
Typically resolves with abstinence from alcohol.
What occurs in intravascular haemolysis?
Free haemoglobin is released and binds to haptoglobin. As haptoglobin becomes saturated, haemoglobin binds to albumin forming methaemalbumin, which can be detected by Schumm’s test. Free haemoglobin is excreted in the urine as haemoglobinuria and haemosiderinuria.
What are the causes of intravascular haemolysis?
Mismatched blood transfusion, G6PD deficiency, red cell fragmentation (heart valves, TTP, DIC, HUS), paroxysmal nocturnal haemoglobinuria, and cold autoimmune haemolytic anaemia.
What are the causes of extravascular haemolysis?
Haemoglobinopathies (sickle cell, thalassaemia), hereditary spherocytosis, haemolytic disease of the newborn, and warm autoimmune haemolytic anaemia.
What is a unique aspect of G6PD deficiency?
Strictly speaking, there is an element of extravascular haemolysis in G6PD deficiency, although it is usually classified as an intravascular cause.
What is iron deficiency anaemia?
Iron deficiency anaemia is the most common anaemia worldwide, caused by a deficiency of iron leading to a reduction in red blood cells/haemoglobin.
Who has the highest incidence of iron deficiency anaemia?
Preschool-age children have the highest prevalence of iron deficiency anaemia.
What are the main causes of iron deficiency anaemia?
The main causes are excessive blood loss, inadequate dietary intake, poor intestinal absorption, and increased iron requirements.
What is the most common cause of excessive blood loss in pre-menopausal women?
Menorrhagia is the most common cause of excessive blood loss in pre-menopausal women.