Anaemia

Question 1

Causes of megaloblastic anaemia?

Answer 1

• Folate deficiency
• Vitamin B12 (cobalamin) deficiency
• Myelodysplastic syndrome (refractory anaemia)
• Drugs:
  
  • Anti-folate drugs e.g. Methotrexate
  • Drugs which affect DNA synthesis e.g. Cytosine Arabinoside

Question 2

What kinds of food is folate found in?

Answer 2

green leafy vegetables

liver, yeast, spinach, other greens, mushrooms and nuts

vitamin B9

Question 3

Answer 3

MEGALOBLASTIC ANAEMIA showing hypersegmented neutrophils & oval macrocytes

Oval macrocytosis, usually with anisocytosis and poikilocytosis, is the main feature. The MCV is usually >100 fL. Some of the neutrophils are hypersegmented (more than five nuclear lobes = right shift).

Leukopaenia and thrombocytopaenia are usually not severe.

Ineffective erythropoiesis → death of nucleated red cells in the marrow (intra-medullary haemolysis).

Question 4

Who is usually B12 deficient?

Answer 4

vegans

Question 5

What is pernicious anaemia? Who does it occur most commonly in?

Answer 5

PA may be defined as a severe lack of intrinsic factor due to gastric atrophy.

• It is a common disease in north Europeans but occurs in all countries and ethnic groups.
• Intrinsic factor is required for absorption of vitamin B12 in the ileum.
• The disease occurs more commonly in close relatives and in persons with other autoimmune diseases, e.g. thyroid diseases, vitiligo, hypoparathyroidism and Addison’s disease. It is also associated with hypogammaglobulinaemia, with premature graying or blue eyes, and in persons of blood group A
• The life expectancy is normal in women once regular treatment has begun. Men have a slightly subnormal life expectancy as a result of a higher incidence of carcinoma of the stomach

Question 6

What investigations should you do if you are suspecting pernicious anaemia

Answer 6

• S-Vitamin B12 level to confirm diagnosis, as well as s-Folate level and Iron studies, as a mixed deficiency may be present.
• Gastric Biopsy shows atrophy of all layers and an absence of parietal and chief cells

Antibodies!!!!!!!!!!!!!!!

Intrinsic Factor (IF) antibody:

Two types of this antibody may be found in the sera of patients with PA.

∙ “Blocking,” or type I, antibody prevents the combination of IF and vitamin B12

∙ “Binding,” or type II, antibody prevents attachment of IF to ileal mucosa.

Parietal cell antibody

Present in the sera of almost 90% of adult patients with PA but is not specific for PA.

Question 7

Treatment of vitamin B12 def?

Answer 7

When treatment is commenced for Vitamin B12 deficiency, or a mixed Vitamin B12 and folate deficiency, the patient should receive a loading dose of Vitamin B12 prior to commencement of folate therapy, to prevent precipitation of subacute combined degeneration of the cord.

Question 8

Why do people with hypothyroidism get anaemia?

Answer 8

1. Low levels of thyroxine may cause bone marrow hypoplasia
2. Hypercholesterolaemia → round macrocytes, which may/may not have a shorter lifespan than normal
3. Menorrhagia → iron deficiency
4. Associated pernicious anaemia in patients whose hypothyroidism has been caused by Hashimoto’s thyroiditis
5. Folate absorption from the GIT may be impaired in hypothyroidism