Anaemia Flashcards
What are the two types of autoimmune haemolytic anaemia (AIHA)?
‘Warm’ and ‘cold’ types.
What is the most common cause of AIHA?
It is most commonly idiopathic.
What are some secondary causes of AIHA?
Lymphoproliferative disorder, infection, or drugs.
What are the general features of haemolytic anaemia?
Anaemia, reticulocytosis, low haptoglobin, raised lactate dehydrogenase (LDH) and indirect bilirubin, blood film showing spherocytes and reticulocytes.
What is a specific feature of autoimmune haemolytic anaemia?
Positive direct antiglobulin test (Coombs’ test).
What type of antibody is involved in warm AIHA?
Usually IgG.
At what temperature does warm AIHA cause haemolysis best?
At body temperature.
Where does haemolysis tend to occur in warm AIHA?
In extravascular sites, for example the spleen.
What are some causes of warm AIHA?
Idiopathic, autoimmune disease (e.g. systemic lupus erythematosus), neoplasia, lymphoma, chronic lymphocytic leukaemia, drugs (e.g. methyldopa).
What is the first-line management for warm AIHA?
Treatment of any underlying disorder, steroids (+/- rituximab).
What type of antibody is involved in cold AIHA?
Usually IgM.
At what temperature does cold AIHA cause haemolysis best?
At 4 degrees Celsius.
How is haemolysis mediated in cold AIHA?
By complement and is more commonly intravascular.
What symptoms may be associated with cold AIHA?
Symptoms of Raynaud’s and acrocynosis.
How do patients with cold AIHA respond to steroids?
Patients respond less well to steroids.
What are some causes of cold AIHA?
Neoplasia (e.g. lymphoma), infections (e.g. mycoplasma, EBV).
Can systemic lupus erythematosus be associated with AIHA?
Yes, it can rarely be associated with a mixed-type autoimmune haemolytic anaemia.
What are the subtypes of hereditary haemolytic anaemias?
Hereditary haemolytic anaemias can be subdivided into membrane, metabolism, or haemoglobin defects.
What are the hereditary causes of membrane defects?
Hereditary causes of membrane defects include hereditary spherocytosis and elliptocytosis.
What is a hereditary metabolic defect that causes haemolytic anaemia?
G6PD deficiency is a hereditary metabolic defect that causes haemolytic anaemia.
What are the haemoglobinopathies associated with hereditary haemolytic anaemias?
Sickle cell disease and thalassaemia are haemoglobinopathies associated with hereditary haemolytic anaemias.
What are the subtypes 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?
Immune causes (Coombs-positive) include autoimmune (warm/cold antibody type), alloimmune (transfusion reaction, haemolytic disease newborn), and drug-related causes (methyldopa, penicillin).
What are the non-immune causes of acquired haemolytic anaemias?
Non-immune causes (Coombs-negative) include microangiopathic haemolytic anaemia (MAHA), prosthetic heart valves, paroxysmal nocturnal haemoglobinuria, infections (malaria), drug-related causes (dapsone), and Zieve syndrome.
What is Zieve syndrome?
Zieve syndrome is a rare clinical syndrome of Coombs-negative haemolysis, cholestatic jaundice, and transient hyperlipidaemia associated with heavy alcohol use, typically following a binge. It typically resolves with abstinence from alcohol.
What occurs in intravascular haemolysis?
Free haemoglobin is released which then binds to haptoglobin. As haptoglobin becomes saturated, haemoglobin binds to albumin forming methaemalbumin (detected by Schumm’s test). Free haemoglobin is excreted in the urine as haemoglobinuria, haemosiderinuria.
What are the causes of intravascular haemolysis?
Mismatched blood transfusion, G6PD deficiency, red cell fragmentation (heart valves, TTP, DIC, HUS), paroxysmal nocturnal haemoglobinuria, cold autoimmune haemolytic anaemia.
What are the causes of extravascular haemolysis?
Haemoglobinopathies (sickle cell, thalassaemia), hereditary spherocytosis, haemolytic disease of newborn, warm autoimmune haemolytic anaemia.
Is G6PD deficiency classified as intravascular or extravascular haemolysis?
G6PD deficiency is usually classified as an intravascular cause, although there is an element of extravascular haemolysis.
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.
What should always be suspected in men with gastrointestinal bleeding?
Always suspect colon cancer in men with gastrointestinal bleeding.
Why are vegans and vegetarians at higher risk for iron deficiency anaemia?
Vegans and vegetarians may develop iron deficiency anaemia due to inadequate dietary intake of iron, as meat is a good source of iron.
What conditions can lead to poor intestinal absorption of iron?
Conditions affecting the small intestine, such as coeliac disease, can prevent sufficient iron absorption.
When do children have increased iron requirements?
Children have increased iron demands during periods of rapid growth.
What are some features of iron deficiency anaemia?
Features include fatigue, shortness of breath on exertion, palpitations, pallor, nail changes, hair loss, atrophic glossitis, post-cricoid webs, and angular stomatitis.
What is the most important step in investigating iron deficiency anaemia?
Taking a history is the most important step in looking for potential causes of iron deficiency.
What does a full blood count (FBC) show in iron deficiency anaemia?
FBC demonstrates hypochromic microcytic anaemia.
What does low serum ferritin indicate?
Low serum ferritin indicates low iron stores, but can be raised during inflammation.
What does a high total iron-binding capacity (TIBC) indicate?
A high TIBC reflects low iron stores.
What should be done for males and post-menopausal females with unexplained iron-deficiency anaemia?
They should be considered for further gastrointestinal investigations.
What is the management for iron deficiency anaemia?
Identify and manage the underlying cause, and consider malignancy exclusion.
What is the recommended treatment for iron deficiency anaemia?
Oral ferrous sulfate is recommended, and patients should continue taking iron for 3 months after correction.
What are common side effects of iron supplementation?
Common side effects include nausea, abdominal pain, constipation, and diarrhoea.
What foods are recommended for an iron-rich diet?
An iron-rich diet includes dark-green leafy vegetables, meat, and iron-fortified bread.
Iron deficiency anaemia - Serum iron
Low < 8
Example: Serum iron levels are critically low in iron deficiency anaemia.
Anaemia of chronic disease - Serum iron
Low < 15
Example: Serum iron levels may be low but not as critically low as in iron deficiency anaemia.
Iron deficiency anaemia - TIBC
High
Example: Total iron-binding capacity (TIBC) is elevated in iron deficiency anaemia.
Anaemia of chronic disease - TIBC
Low
Example: TIBC is typically low in anaemia of chronic disease.
Iron deficiency anaemia - Transferrin saturation
Low
Example: Transferrin saturation is low in iron deficiency anaemia.
Anaemia of chronic disease - Transferrin saturation
Low
Example: Transferrin saturation remains low in anaemia of chronic disease.
Iron deficiency anaemia - Ferritin
Low
Example: Ferritin levels are low in iron deficiency anaemia.
Anaemia of chronic disease - Ferritin
High
Example: Ferritin levels are often high in anaemia of chronic disease.
What are the two categories of causes for macrocytic anaemia?
Megaloblastic causes and normoblastic causes.
What are the megaloblastic causes of macrocytic anaemia?
Vitamin B12 deficiency and folate deficiency.
Example: Folate deficiency can be secondary to methotrexate.
What are the normoblastic causes of macrocytic anaemia?
Alcohol, liver disease, hypothyroidism, pregnancy, reticulocytosis, myelodysplasia, and drugs such as cytotoxics.
What are the causes of microcytic anaemia?
- Iron-deficiency anaemia
- Thalassaemia
- Congenital sideroblastic anaemia
- Anaemia of chronic disease (more commonly a normocytic, normochromic picture)
- Lead poisoning
What should a normal haemoglobin level with microcytosis raise the possibility of?
Polycythaemia rubra vera, especially in patients not at risk of thalassaemia.
What should be urgently investigated in elderly patients with new onset microcytic anaemia?
Underlying malignancy.
How is microcytosis in beta-thalassaemia minor characterized?
The microcytosis is often disproportionate to the anaemia.
What is anaemia?
Anaemia is a condition characterized by a deficiency of red blood cells or hemoglobin in the blood.
What are the causes of normocytic anaemia?
Causes of normocytic anaemia include:
1. Anaemia of chronic disease
2. Chronic kidney disease
3. Aplastic anaemia
4. Haemolytic anaemia
5. Acute blood loss
Iron deficiency anemia vs AOCD - serum iron, TIBC, transferrin saturation, Ferritin
Ascites SAAG < 11 vs SAAG > 11
