MEH: Anaemia, B12 and folate, Polycythaemia Flashcards
Define the term anaemia.
A condition in which there is a deficiency of red cells or of haemoglobin in the blood, resulting in pallor and weariness.
Name some mechanisms which can result in anaemia.
- reduced erythropoiesus
- Dyserythropoiesis
- Haemoglobin abnormalities
- Vit B12 deficiency
- Folate deficiency
- Red cell membrane deficiencies
- Red cell enzyme defects
- Loss of red cells
- Removal of red cells by RES
Describe important causes of microcytic, normocytic and macrocytic anaemias.
Anaemia of chronic disease (ACD), seen in inflammatory conditions such as Rheumatoid arthritis, occurs when iron stored in macrophages is not released for use in bone marrow.
Name some common causes of a haemolytic anaemia.
- Autoimmune
- Infections
- Enlarged spleen
- Tumours
What clinical land markers are present when a patient has haemolytic anaemia?
- Increased reticulocytes (as the bone marrow attempts to compensate)
- Raised bilirubin (breakdown of haem)
- Raised LDH (red cells rich in this enzyme)
Describe the haematological investigations in patients with suspected iron deficiency.
1
Describe the haematological investigations in patients with suspected vit B12 deficiency.
1
Describe the haematological investigations in patients with suspected folate deficiency.
1
Name some common clinical features associated with iron deficiency.
1
Name some common clinical features associated with vit B12 deficiency.
1
Name some common clinical features associated with folate deficiency.
1
Describe the role and complications associated with haematinic replacement treatment.
1
Describe the clinical and haematological features of the anaemia of chronic disease.
1
Explain how the features of the anaemia of chronic disease is distinguished from iron
deficiency.
1
Explain the common haematological abnormalities that can occur in patients with non-haematological systemic diseases.
1
What is haemolytic anaemia?
Increased red cell destruction leading to anaemia.
Why might there be reduced erythropoiesis?
- Chronic kidney disease stops the kidney creating EPO
- Empty bone marrow
- Bone marrow infiltrated by cancer cells
What is dyserythropoiesis?
Defective development of erythrocytes.
How do humans acquire B12?
Eating foods of animal origin
How is B12 delivered to tissues?
B12 is combined with IF produced by parietal cells in the stomach. IF-B12 complex is absorbed by ileum and in the portal blood B12 is bound to plasma protein transcobalamin which delivers it to tissues.
How could B12 deficiency result from?
- Vegan diet
- Autoimmune destruction of partial cells
- disease of terminal ileum e.g. Crohns
Where does absorption of folate occur?
Duodenum and jejunum
What are dietary floaters converted into?
MethylTHF
Where is the inheritance pathology and pattern of sickle cell?
- valine for glutamine
- autosomal recessive
How do thalasseamias result in anaemia?
Insoluble aggregates of alpha chains contribute to the defective nature of the red cell. This leads to excessive destruction of mature red cells in the spleen leading to less RBC in circulation.
What is a major cause of premature death with patients with thalassaemias?
Iron over load due to excessive absorption of dietary iron due to ineffective haematooiesis. Also repeated blood transfusions.
What enzyme is commonly deficient in red cell metabolism leading to anaemia?
G-6-P dehydrogenase
OR pyruvate kinase
