Macrocytic anaemias Flashcards Preview

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Flashcards in Macrocytic anaemias Deck (13)
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What is released by the salivary glands for B12 absorption and what is its importance?

Haptocorrin/transcobalamin I (TCN1)

Protects vitamin B12 from acid digestion


What degrades Haptocorrin/transcobalamin I (TCN1)?

Pancreatic proteases in duodenum


What allows absorption of B12 in the terminal ileum?

Intrinsic factor


What are the causes of B12 deficiency?

1. Nutritional (vegan, poor diet, pregnancy)
2. Malabsorption
Gastric (Surgery, pernicious anaemia)
Intestine (Ileal resection, fish tapeworm and tropical sprue)
3. Get malabsorption of B12 but not deficiency in Crohn’s disease, Coeliac, CF


What are the symptoms associated with B12 deficiency?

• Gradual onset
• ‘Lemon tinge’ due to pallor (anaemia) and mild jaundice (haemolysis)
• Glossitis (inflammation of the tongue)
• Angular cheilitis (inflammation of the corners of the mouth)
• Neuropathy


What is pernicious anaemia?

Autoimmune condition where atrophic gastritis leads to reduced secretion of IF from parietal cells of the stomach.

Dietary B12 remains unbound and cannot be absorbed by terminal ileum.


What diagnoses B12 deficiency?

• Low Hb
• High MCV
• Low serum B12/cobalamin
• Low reticulocytes
• Hypersegmented neutrophils (5+ lobes)
• Low WCC and platelets if severe


What diagnoses pernicious anaemia?

• IF antibodies (more sensitive)
• Parietal cell antibodies


How do you treat B12 deficiency?

- Hydroxocobalamin injections
Given frequently until B12 restored and then every 2-3 months

-Oral cyanocobalamin


What can cause folate deficiency?

1. Nutritional (Poor diet, goat’s milk only)
2. Intestinal (Coeliac, jejunal resection)
3. Excessive requirement (Pregnancy, prematurity)
4. Increased turnover (Chronic haemolysis, severe skin disease)
5. Drugs (Methotrexate, anticonvulsants)
6. Excess low (Dialysis)
7. Miscellaneous (Alcohol)


How do you diagnose folate deficiency?

Serum folate <7 nanomol/L


How do you treat folate deficiency?

Folic acid 5mg o.d. for 4 months


What do you monitor after treatment has started for B12 and folate deficiency?

FBC and reticulocyte count in 7-10 days
- Risen above normal range = good
- No rise = check serum folate

8 weeks – measure iron and folate levels
- MCV should have normalised