Nutritional Anaemias

Iron Found in most animal products – not so available from vegetarian diet Body does not easily absorb or lose iron Deficiency state common - often subclinical complication Iron metabolism is discussed in another presentation

Vitamin B12 Vitamin B12 is found in all animal products, so nutritional deficiency is rare in all except the fussiest eaters It is not absorbed by the gut UNLESS it is bound to Intrinsic Factor (IF) which is secreted by parietal cells in the stomach lining It is then carried around the body by three transport proteins - transcobalamins 1, 2 & 3. In health the body stores several years worth of Vitamin B12 Measured in laboratory by immunoassay

Deficiency was historically investigated with the Schilling Test Inject a massive dose of Vitamin B12  corrects deficiency  fills stores  any more B12 absorbed will then be excreted Orally feed them Vit B12 with Co 57 label and Vit B12+IF with Co 58 label Collect urine for 24 hours If both isotopes are in the urine, the patient has no absorbtion problem. If there is only the Co 58 label in the urine the patient has an underlying absorption problem Vitamin B12

Deficiency was historically investigated with the Schilling’s Test Schilling’s test is no longer performed Feeding radio-isotopes to patients is frowned upon (!) Intrinsic Factor antibody assay instead nowadays Vitamin B12

Most likely causes of deficiency: 1Ca stomach 2Post gastrectomy state 3Auto - Immune disease 4Dietary insufficiency is very unlikely Classic pernicious anaemia is case 3 Vitamin B12

Found in fresh fruit & vegetables, but is destroyed by cooking and storage Body easily absorbs folate, but stores only a few months worth Deficiency state common - often subclinical complication Measured in laboratory by immunoassay Folate

Two real causes of a nutritional anaemia 1Dietary insufficiency 2Absorption problems Nutritional Anaemias

Dietary insufficiency Iron is in your diet  though your diet is better at holding iron than you are at absorbing it B12 is in your diet  unless strict vegan Folate is probably in your dinner  unless you don’t eat properly  “tea & toast”  Gran’s been boiling the sprouts

Absorption in Health Iron  The body isn’t very good at absorbing iron at the best of times.  And certain foods don’t give up their iron B12  Actively absorbed with intrinsic factor Folate  Easily absorbed

Intestinal hurry  The best diet in the world needs time to be absorbed. The gut function must be OK  Gut disease  Radiation  auto immune problems  carcinoma Increased demand  Growth  Pregnancy  disease  (How borderline is your diet !!) Absorption problems

Laboratory Investigations First line test: Hb Is a “normal” Hb level indicative of no deficiency?

Cell size – the MCV High ?? B12 deficiency ?? Folate deficiency Low ?? Fe deficiency Laboratory Investigations

Specific Assays B12 Folate Iron ? - why not so useful ? Ferritin Iron binding Laboratory Investigations

HOMOCYSTEINE METHIONINE SYNTHASE METHYMALONYL CoA SUCCINYL CoA DEOXYLADENOSYL B 12 Homocysteine

METHYL THF THF HOMOCYSTEINE METHIONINE SYNTHASE Homocysteine

Elevated with both B 12 and folate deficiency Homocysteine

Treatments These are anaemias of deficiency !!!! So the treatment is obvious !!!!!!

Failure to Respond to Iron Therapy Non Compliance Defective absorption Continuing blood loss Concurrent B 12 or folate deficiency Wrong diagnosis

Failure to Respond to B 12 Therapy Non Compliance Defective absorption Concurrent iron or folate deficiency Wrong diagnosis

Failure to Respond to Folate Therapy Non Compliance Defective absorption Concurrent iron or B 12 deficiency Wrong diagnosis