Summary BNF Chapter 9 - Blood & Nutrition

ANAEMIAS
OVERVIEW:
- Anaemia: when Hb levels in blood fall below normal levels – can be due to:
o Less RBCs in blood
o Less functional Hb in each RBC
- Either way, there’s less oxygenated blood available for tissues

TYPES OF ANAEMIA:
1- Fe-deficiency (IDA) – due to menstruation, pregnancy, malabsorption (e.g. coeliac)

2- Chronic Kidney Disease (ACKD) – renal dysfunction  less erythropoietin synthesis
 less action on bone marrow  less erythropoiesis

3- Megaloblastic anaemia (folate or B12 deficiency) – reduced availability of
haematinics needed for healthy erythropoiesis – due to drug ADRs (MTX) &
malabsorption

4- Glucose-6-phosphate dehydrogenase (G6PD) deficiency – genetic mutation 
deficiency in G6PD enzyme less protection of RBCs from ROS  eryptosis 
haemolytic anaemia

5- Sickle cell anaemia – mutation  sickle-shaped Hb  undergo agglomeration in
deoxygenated states  sickling & reduced flexibility of RBCs  vascular occlusion 
hypoxia  pain crisis

IRON-DEFICIENCY ANAEMIA – Most common type of anaemia
CAUSES:
- Menorrhagia (most common cause)
- Pregnancy (more blood redirected for foetal growth)
- Malabsorption state (IBDs, Coeliac disease, Gastrectomy)

Very uncommon for healthy men & post-menopausal women to develop IDA (unless they
have a gastric issue)

SYMPTOMS:
- Pale skin & gums
- Lethargy & headaches
- Fatigue & Dyspnoea
- Palpitations
- Angular cheilitis (aka stomatitis) – inflamed, cracked
corners of mouth (due to candida)
- Glossitis – inflamed, swollen tongue
- Pica – eating/craving non-food items

, ORAL IRON REPLACEMENT – Ferrous Salts
TYPES:
- Ferrous Sulphate – 65mg elemental Fe (best absorption but harshest GI ADRs)
- Ferrous Fumarate – 65mg elemental Fe
- Ferrous Gluconate – 35mg elemental Fe

Difference in absorption is MINIMAL between the salts – choice depends on pt.’s
tolerance to ADRs and cost of medicine

DOSE:
- TREAT IDA: 100-200mg elemental Fe daily e.g.
o Ferrous sulphate 200mg BD-TDS
This dose is to be continued for 3 months after restoring normal Fe levels

- PREVENT IDA: normally ONE dose daily e.g.
o Ferrous sulphate 200mg OD
This dose is to be continued for as long as the pt has risk factors for IDA e.g. IBDs (then
may be taken lifelong)

SIDE EFFECTS:
- GASTRO ADRs: constipation, loss of appetite, epigastric pain
- Darkened/black stools: most Fe is excreted (i.e. not absorbed)

COUNSELLING POINTS:
- Absorption best when on empty stomach (if tolerated)
- If GI ADRs are not tolerated – still safe to take with food
- Vit. C promotes absorption – take with orange juice (although not necessary)
- Avoid Ca2+- rich foods & caffeine with doses – leave TWO HOUR GAP
- Not all IDA symptoms will be treated at the same time e.g.
o Headaches & fatigue may clear within a few days
o Cheilitis & glossitis may clear within a few weeks

PARENTERAL IRON – Iron Sucrose, Iron Dextran

WHEN IS PARENTETAL Fe USED:
- Used when oral therapy is UNSUCCESSFUL – many CAUSES:
o Pt intolerant of GI effects
o Oral doses too low to offset Fe-loss through menorrhagia
o Severe malabsorption state
- Also given alongside IV cytotoxics (due to their myelosuppressive effects)

Parenteral Fe does NOT work any faster than oral Fe – only advantage is that higher doses
can be given (bypasses the issue of GI absorption) & there’s no GI ADRs

ANAPHYLAXIS – serious SIDE EFFECT of parenteral Fe:
- Can occur even if pt did not have a HS reaction on previous exposure
- RISK FACTORS:
o Pts with ATOPY (e.g. asthma, eczema – already have hypersensitive immune system)
o Pts with any known allergy