Anaemia - covered in GI Flashcards
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.
What should be suspected in men and post-menopausal women with gastrointestinal bleeding?
Always suspect colon cancer in cases of gastrointestinal bleeding.
Why are vegans and vegetarians more likely to develop iron deficiency anaemia?
Vegans and vegetarians are more likely to develop iron deficiency anaemia due to a lack of meat in their diet, which is a good source of iron.
What conditions can affect poor intestinal absorption of iron?
Conditions such as coeliac disease can prevent sufficient iron absorption.
What increased iron requirements exist during growth and pregnancy?
Children have increased iron demands during rapid growth, and women have increased demands during pregnancy.
What are some common features of iron deficiency anaemia?
Common 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) demonstrate 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) reflect?
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 approach for iron deficiency anaemia?
Identify and manage the underlying cause, and exclude malignancy through adequate history and investigations.
What is a common oral supplement for iron deficiency anaemia?
Oral ferrous sulfate is commonly used, and patients should continue for 3 months after correction.
What are some common side effects of iron supplementation?
Common side effects include nausea, abdominal pain, constipation, and diarrhoea.
What foods are included in an iron-rich diet?
An iron-rich diet includes dark-green leafy vegetables, meat, and iron-fortified bread.
Iron deficiency anaemia serum iron level
Low < 8
Compared to Anaemia of chronic disease which is Low < 15.
Anaemia of chronic disease serum iron level
Low < 15
Compared to Iron deficiency anaemia which is Low < 8.
Iron deficiency anaemia TIBC level
High
Compared to Anaemia of chronic disease which is Low.
Anaemia of chronic disease TIBC level
Low
Compared to Iron deficiency anaemia which is High.
Iron deficiency anaemia transferrin saturation
Low
Compared to Anaemia of chronic disease which is also Low.
Anaemia of chronic disease transferrin saturation
Low
Compared to Iron deficiency anaemia which is also Low.
Iron deficiency anaemia ferritin level
Low
Compared to Anaemia of chronic disease which is High.
Anaemia of chronic disease ferritin level
High
Compared to Iron deficiency anaemia which is Low.
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 (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 done for new onset microcytic anaemia in elderly patients?
It should be urgently investigated to exclude underlying malignancy.
What is notable about microcytosis in beta-thalassaemia minor?
The microcytosis is often disproportionate to the anaemia.
What is normocytic anaemia?
A type of anaemia characterized by normal-sized red blood cells.
What are the causes of normocytic anaemia?
Causes include:
1. Anaemia of chronic disease
2. Chronic kidney disease
3. Aplastic anaemia
4. Haemolytic anaemia
5. Acute blood loss
