iron deficiency anaemia

see also:

• anaemia
• ferritin
• MJA Guidelines - Diagnosis and management of iron deficiency anaemia: a clinical update
• GP referral of community based patients requiring transfusion at Western Health
• Nat. Blood Authority Australia March 2016: Iron product choice and dose calculation for adults (pdf)

• always attempt to determine the cause of iron deficiency to ensure underlying malignancy or PU disease is excluded.
• recommended daily iron intake depends upon age and gender:
  • pregnant women = 27mg/d
  • premenopausal women = 18mg/d
• correcting iron deficiency anaemia takes 2-4 months of oral Rx assuming the underlying cause is managed, but replenishing stores takes another 3-6 months of oral Rx after Hb has returned to normal
• confirm response to oral iron Rx by checking Hb in 3-4 weeks, it should have risen by 20g/L
• parenteral iron can usually be avoided, but if needed, it should be given iv as im doses are painful, stain the skin and are poorly absorbed.

• rapid growth (eg. infant, adolescent)
• pregnancy
• erythropoietin therapy

• GIT blood loss
  • peptic ulcer disease (PUD)
  • drug Rx - aspirin, non-steroidal anti-inflammatory drugs (NSAIDs)
  • stomach cancer
  • colorectal cancer (bowel cancer)
  • infection (eg. hookworm)
  • angiodysplasia
• menstrual blood loss
• blood donation
• post-operative or major trauma

• inadequate diet (eg. vegan)
• malabsorption
  • hypochlorhydria (eg. long term proton pump inhibitors (PPIs) Rx
  • disease - (eg. coeliac disease)
  • surgery - (eg. post-gastrectomy)
  • inflammation
  • genetic factors:
    • loss-of-function (LOF) mutation in the gene PTPN2 (protein tyrosine phosphatase non-receptor type 2)
      • this is a key negative regulator of JAK1–STAT3 pathway activation
      • LOF mutations caused by single nucleotide polymorphisms (SNPs) in PTPN2 increase the risk for inflammatory bowel disease (IBD)
        • in mice studies, LOF mutations also result in reduced levels of DMT1, a key iron-absorbing protein located in the intestinal epithelial cells¹⁾
      • found in 14-16% of the general population and 19-20% of the IBD population
    • loss of function of TPC1 ion channels via mutation in TPCN1 gene
      • TCP1 activity influences both the absorption of iron from the plasma membrane and the pH value in endosomes that release iron into the cytosol based on pH value²⁾

• adults: 100-210mg daily in divided doses
• children: 2-3mg/kg up to 7mg/kg (max. 210mg) daily in divided doses

• Ferro Liquid 30mg/ml ferrous sulfate = 6mg/ml elemental iron
• FGF - CR tablet 300mcg folic acid plus 250mg dried ferrous sulfate = 80mg elemental iron
• Fefol - capsule 300mcg folic acid plus 270mg dried ferrous sulfate = 87.4mg elemental iron
• Ferrograd C - CR tablet 500mg vitamin C plus 325mg dried ferrous sulfate = 105mg elemental iron

• iron absorption is reduced by antacids and calcium - separate dosage times by some hours
• iron reduces the absorption of bisphosphonates, levodopa, carbidopa, methyldopa and thyroid hormones
• iron absorption is reduced by and reduces the absorption of oral quinolones and tetracyclines

• it is tolerated better if started at a low dose
• abdominal pain
• nausea / vomiting
• constipation and diarrhoea
• black stools
• oral liquid may discolor teeth but this can be prevented by diluting with water and drinking through a straw
• accidental or intentional ingestion may be fatal - see iron poisoning

• lamb kidney 11mg/100g
• lean beef 3mg/100g
• chicken or fish 1mg/100g
• spinach 4mg/100g
• wholemeal bread or hard boiled eggs 2mg/100g

• see intravenous iron Rx