Iron, B12 + folate Flashcards
Fe deficiency management
confirm iron deficiency anaemia
determine cause
treat anaemia
treat underlying
What type of anaemia is Fe deficiency anaemia?
microcytic hypochromic
target cells present
What type of anaemia is B12 deficiency anaemia?
macrocytic
(megaloblastic)
What type of anaemia is folate deficiency anaemia?
macrocytic
(megaloblastic)
Iron deficiency causes
Inadequate diet
Increased requirements (pregnancy, growth)
Malabsorption
Blood loss (menstrual, GI, urinary, lung)
When should you do GI investigations in iron deficiency anaemia?
all men
all post-menopausal women
symptomatic women (eg. blood in stools)
women >45
FH colon cancer
GI causes of iron deficiency anaemia
hookworm infections
oesophago-gastric cancer
coeliac disease
crohn’s disease
gastritis
peptic ulceration
oesophagitis
gastrectomy
NSAID enteritis
meckel’s diverticulum
colon cancer
large polyps
colitis
angiodysplasia
diverticular bleeding
haemorrhoids
Describe iron replacement therapy
(continue for 3 months post Hb stabilisation)
oral ferrous sulphate
ferrous gluconate
sodium ironedetate
ferric maltol
avoid slow release preparations
Describe folic acid
synthesised by bacteria
green veg, offal
biologically active as polyglutamates
small store
requires B12 for biological activity
Describe vitamin B12
synthesised by microorganisms
stable to cooking
large store
essential to folate metabolism
Describe B12 + folate deficiency
affects all cells
rapidly dividing cells most vulnerable (bone marrow precursors, gut epithelium)
B12 deficiency symptoms
neuropathy
optic atrophy
fatigue
headaches
pallor
(can lead to neural tube defects, stroke and dementia)
Fe deficiency symptoms
fatigue
weakness
fast/irregular heartbeat
chest pain
dizziness
restless legs syndrome
failure to thrive in infants
growth retardation in children
pallor
shortness of breath
brittle nails
cold hands + feet
Folate deficiency symptoms
paraesthesia
mouth ulcers
tiredness
Investigation + management of megaloblastic anaemia
confirm haematological diagnosis:
- blood film
- B12 + folate levels
- consider other macrocytosis causes
- bone marrow
provide replacement therapy
determine underlying cause
Macrocytic anaemia megaloblastic causes
B12 deficiency
Folate deficiency
Combined deficiency
Abnormal folate metabolism (methotrexate)
Abnormal DNA synthesis (orotic aciduria, azathioprine, zidovudine)
Myelodysplasia
Macrocytic anaemia non-megaloblastic causes
(not problem with cell division)
Just macrocytosis
Pregnancy
Liver disease
Alcoholism
Reticulocytosis
Hypothyroidism
Drugs
Marrow infiltration
Sideroblastic anaemia
Cold agglutinins
Describe B12 replacement
Parenteral hydroxycobalamin
3 monthly replacement
prophylaxis after total gastrectomy or ileal resection
oral replacement if absorption intact (eg. vegans)
Describe folate replacement
oral folic acid (4 months or continuously)
prophylaxis in pregnancy + preconception (reduce risk of neural tube defects)
prophylaxis for patients with haemolysis or on methotrexate
In combined B12 and folate deficiency, which should be replaced first?
B12 then folate
initial folate may exacerbate neuropathy
Folate deficiency causes
Diet (anorexia, children, elderly, alcoholics)
Increased utilisation:
- physiological = pregnancy, growth
- pathological = haemolysis, cancers, inflammation
Malabsorption (diffuse small bowel diseases)
Urinary loss (haemodialysis)
Drugs (phenytoin, primidone, sulfasalazine, methotrexate)
B12 deficiency causes
Diet (vegan)
Gastric disease (Autoimmune gastritis, major gastrectomy)
Ileal disease (resection, inflammation)
Infections (small bowel bacterial overgrowth, Fish tapeworm)
Pancreatic disease
Transcobalamin-2 deficiency
B12 destruction (nitrous oxide)
B12 deficiency investigations
dietary history
autoantibodies (anti-parietal cell, anti-intrinsic factor)
B12 absorption tests
small bowel FT + biopsy
gastric biopsy
gastric + pancreatic function tests
Folate deficiency investigation
dietary history
autoantibodies (anti-gliadin, anti-endomysial)
duodenal biopsy
consider systemic diseases
Vitamin B12 function
development, myelination, function of CNS
RBC formation, DNA synthesis
Folate function
RBC formation
cell growth + function
works with B6 + B12 to control elevated blood homocysteine
Dietary sources of folate
liver
yeast extract
green leafy vegetables
legumes (beans, lentils)
orange juice
fortified cereals
Dietary sources of vitamin B12
Products of animal origin:
- meat (especially liver)
- poultry
- fish
- milk + dairy products
- eggs
fortified breakfast cereals
fermented foods (eg. sauerkraut)
Vulnerable groups for nutritional anaemias
Infants + young children (iron)
Vegans (iron + B12)
Pregnant women (iron + folate)
Elderly (iron, folate + B12)
Low income
Ethnic minorities
Signs of iron deficiency in infants
poor weight gain
frequent infections
developmental delay
behavioural disorders
Why is anaemia more common in the elderly?
impaired absorption (particularly B12)
dental problems (restricted food choice)
poor quality meals in institutions
lower socioeconomic status
less mobile (restricted shopping)
mental problems (dementia, depression)
lower physical activity requires lower energy intake (less chance of taking in adequate nutrients)
Why can serum folate levels be unreliable?
a single meal containing folate can rapidly elevate serum folate levels
must do further tests if folate levels are borderline
Ferrous sulphate side effects
metallic taste
constipation
black, tarry stools
Anaemia of chronic disease features
Normochromic, normocytic or mildly hypochromic
mild + non-progressive anaemia
serum iron and TIBC reduced
serum ferritin normal/platelets
Transferrin saturation low
