Hypochromic, microcytic anaemias Flashcards
What is iron deficiency anaemia?
Iron deficiency is the most common cause of anaemia in the world, affecting 30% of the world’s population. This is because of the body’s limited ability to absorb iron and the frequent loss of iron owing to haemorrhage.
Which form of iron is most readily absorbed?
Ferrous - Ferric form is most abundant, but ferrous is more readily absorbed
What is the average daily intake of iron?
15-20 mg, 10% of which is absorbed. This can increase to 20-30% in those who are iron deficient or pregnant
What are the two groups of sources of iron?
- Haem iron - from haemoglobin and myoglobin in red or organ meats
- Non-Haem Iron - fortified cereals
What are causes of iron deficiency anaemia?
- Blood loss
- Increased demands such as growth and pregnancy
- Decreased absorption (e.g. post-gastrectomy)
- Poor intake
What are examples of blood loss that can lead to iron deficiency anaemia?
- Menorrhagia
- GI bleeding
If someone had hypochromic, microcytic anaemia, what investigation would you do?
Serum Ferritin
If someone had a microcytic hypochromic anaemia and a low serum ferritin, what would the diagnosis be?
Iron deficiency anaemia
What other iron studies could you do to aid the diagnosis of iron deficiency anaemia?
- Serum Iron levels - Decreased
- Total iron binding capacity - Raised
- Serum soluble transferrin receptors - raised
How would you approach determining the cause of iron deficiency anaemia?
History - look for clear history of menorrhagia. If not, look for GI blood loss - colonoscopy, endoscopy, gastroscopy, sigmoidoscopy, stool microscopy etc.
If someone had iron deficiency anaemia with no obvious cause of bleeding, what would you do?
Thorough GI investigation to look for GI bleeding source
How would you manage someone with iron deficiency anaemia?
Correct cause
- Diet - red meat
- Ulcer therapy
- Surgery if bleeding
Correct anaemia
- Ferrous Sulphate - oral or IV
- Consider transfusion
What are side effects of ferrous sulphate?
- Nausea
- Abdominal discomfort
- Diarrhoea/constipation
- Black stools
How much should Hb increase by per week if someone is given ferrous sulphate to treat iron deficiency anaemia?
10g/L/week
What is diagnostic feature on blood film of sideroblastic anaemia?
Ring sideroblasts - accumulation of iron in the mitochondria of erythroblasts owing to disordered haem synthesis forming a ring of iron granules around the nucleus that can be seen with Perls’ reaction.
The blood film is often dimorphic; ineffective haem synthesis is responsible for the microcytic hypochromic cells
When treating iron deficiency anaemia, how long should you give them ferrous sulphate for?
Until haemoglobin is normal and for 3 months
What would be the iron profile of someone with sideroblastic anaemia?
- Iron - Increased
- TIBC - Normal
- Ferritin - Increased
What iron profile would someone with Thalassemia have?
- Ferritin - normal
- Iron - normal
- TIBC - normal
If someone had hypochromic, microcytic anaemia and they had a normal or increased serum ferritin, what would you think would be the cause?
- Anaemia of chronic disease
- Thalassemia
- Sideroblastic anaemia
What is sideroblastic anaemia?
Sideroblastic anaemias are inherited or acquired disorders characterized by a refractory anaemia, a variable number of hypochromic cells in the peripheral blood, and excess iron and ring sideroblasts in the bone marrow.
What are causes of sideroblastic anaemia?
- Myelodysplasia
- Myeloproliferative disorders
- Myeloid leukaemia
- Drugs (e.g. isoniazid)
- Alcohol misuse
- Lead toxicity
What are causes of microcytic hypochromic anaemia?
In order or most common to least:
- Iron deficiency anaemia
- Anaemia of Chronic Disease (30%)
- Thalassaemia
- Sideroblastic anaemia
Remember TAILS - Thalassemia, Anaemia of CD, Iron deficiency, Lead poisoning, Sideroblastic
What is the iron profile of someone with anaemia of chronic disease?
- Serum Iron - reduced
- TIBC - reduced
- Serum ferritin - normal/raised
What signs might you see which would point towards a diagnosis of iron deficiency anaemia?
All in very long standing disease
- Koilonychia
- Brittle nails/hair
- Atrophic glossitis
- Angular stomatitis
- A syndrome of dysphagia and glossitis
What is the following?
Koilonychia
What is the following?
Angular stomatitis - Maculopapular and vesicular lesions grouped on the skin at the corners (or ‘angles’) of the mouth and mucocutaneous junction.
Why does angular stomatitis occur in iron deficiency anaemia?
Iron and other nutrients are necessary to gene transcription for essential cell replication, repair and protection.
Nutrient deficiency leads to impeded protection, repair and replacement of the epithelial cells on the edges of the mouth resulting in atrophic stomatitis.
What is the following?
Atrophic glossitis - The absence or flattening of the filiform papillae of the tongue
Why does atrophic glossitis occur in iron deficiency anaemia?
It is believed that micronutrient deficiency impedes mucosal proliferation.
As cells of the tongue papillae have a high turnover, deficiencies in micronutrients needed for cell proliferation or cell membrane stabilisation may lead to depapillation.
Nutritional deficiency is also thought to change the pattern of microbial flora, thus contributing to glossitis
What differentiates anaemia of chronic disease from iron deficiency anaemia?
- Increased ferritin in AOCD - secondary to inflammatory process underlying the anaemia, as ferritin is a serum reactant protein
- Decreased TIBC in AOCD
What tests are included in iron studies?
- Ferritin
- Serum Iron
- Transferrin/Total iron binding capacity (TIBC)
- Transferrin saturations
What can cause ferritin to rise?
Acute phase protein
- Liver disease
- Malignancy
- Inflammation
What does TIBC show?
Reflects the availibility of iron binding sites on transferrin
What does serum total iron represent?
Measures the total amount of iron in the liquid portion of the blood, nearly all of which is bound to transferrin.
What does measurement of serum ferritin represent?
Measures the level of ferritin, a protein made by almost all cells in response to increased iron to sequester it and prevent it causing toxic damage. The ferritin level reflects the total body iron.
It will be low when there is iron deficiency and high when there is an excess of iron in the body.
What does a measurement of transferrin saturation represent?
Saturation = iron concentration/TIBC
Produces an estimate of how many of transferrin iron-binding sites are occupied; this is called the transferrin saturation. Under normal conditions, transferrin is typically one-third saturated with iron. This means that about two-thirds of its capacity is held in reserve
