Home
Revision Guides
Haematology
Anaemia
Anaemia 2
Leukaemia
Myeloproliferative
Myeloma and Lymphoma
Haemostasis
Blood films
This site is in active development. Please express your opinions on what we should offer.

Anaemia

It is useful to divide the causes of anaemia up on the average size of the red blood cell (the mean corpuscular volume):
Macrocytosis
This can be remembered using the mnemonic FAT RBC : Foetus (pregnancy), Alcohol, Thyroid, Reticulocytosis, B12/Folate, Cirrhosis.
Normocytosis
Acute blood loss, anaemia of chronic disease, marrow infiltration, haemolysis
Microcytosis
The mnemonic "Find Those Small Cells" is useful: Fe deficiency, Thalassaemia, Sideroblastic anaemia, Chronic disease.

Iron Deficiency Anaemia

The absorption of iron daily is 1g. The total body iron is 4mg, 3mg of which is stored in haemoglobin, and 1mg of which is stored in reticuloendothelial cells.

Common causes of iron deficiency anaemia include:

The general clinical features of anaemia include: fatigue, dizziness, shortness of breath, palpitations, angina. The specific features of iron deficiency anaemia are: angular stomatitis (sores and cracks around mouth), glossitis (smooth red sore tongue), koilonychia (spoon shaped nails).

Investigations:

  1. Microcytic hypochromic anaemia.
  2. Low serum ferritin (Fe store in liver proportional to Fe in body) and low Fe
  3. Increased serum transferrin and total binding capacity.
  4. Decreased transferrin saturation.
  5. Absence of Fe stores on bone marrow smear
  6. If the patient is a man, or a post-menopausal woman, then an endoscopy may be indicated to exclude gastrointestinal blood loss
Pale, small red cells

If no cause is found then the treatment is replacement with oral iron.

Anaemia of chronic Disease

This causes a mild to moderate anaemia and has a multifactorial aetiology. It is thought that the main process is a failure to transport iron from reticuloendothelial cells to red blood cells. On investigation it is distinguished from iron deficiency anaemia by a normal or raised serum ferritin. Causes include chronic infection/inflammation, malignancy, uraemia and endocrine disorders. Treatment is of the underlying cause. Eryothropoetin is also sometimes given.

Leukoerythroblastic Anaemia

This occurs when there is marrow infiltration, meaning that insufficient haemopoiesis of red blood cells is possible. An example is myelofibrosis. Immature cells (myelocytes and normoblasts) seen on the peripheral blood film.
Immature (nucleated) red blood cell, and immature white blood cell

Megaloblastic Anaemia

This is a deficiency of B12 or folate, both which are needed for DNA synthesis .

B12 deficiency

B12 is absorbed by combining to Intrinsic Factor, which is secreted by gastric parietal cells. Thus if there is a lack of either B12 or Intrinsic factor then anaemia will result. Common causes:
Intrinsic Factor deficiency
Pernicious anaemia (antibodies to parietal cells in the stomach), gastrectomy, congenital deficiency
Intestinal malabsorption
Diseases of terminal ileum (eg Crohns), blind loops (post surgery), small bowel diverticulae (if colonised then bacteria eat up B12)

Presentation is with anaemia (which can be very low in pernicious anaemia). A peripheral neuropathy termed subacute combined degeneration of the spinal cord can result, resulting in weakness. This does not occur with folate deficiency, and a way to remember it is: B12 - Brain.

On investigation:

  1. Low serum B12.
  2. Blood film: megaloblastic changes.
  3. Pernicious anaemia: parietal cell antibodies, IF antibodies. 
  4. Schilling test, to distinguish between whether the B12 deficiency is due to lack of Intrinsic Factor. Oral radiolabelled B12 is given with intramuscular non-radiolabelled B12. The intramuscular B12 saturates B12 binding proteins in the plasma promoting urinary excretion of radiolabelled B12. Next urine is collected after 24h (anything in urine has been absorbed). If there is less than 10% oral B12 excreted (ii.e. present in the urine), then absorption is impaired. The test is repeated once Intrinsic Factor has been given. If the deficiency due to lack of IF then B12 absorption will be high
More than 7 lobes on a neutrophil

Folic Acid Deficiency

Presentation is very similar to B12 but there is no neurological involvement. Investigation is serum folate.

Causes:

Copyright PassMED, 2008. Disclaimer