Iron deficiency anaemia

Background and Epidemiology

  • Occurs when the body’s iron demand is not met by iron absorption such to cause anaemia
  • It is common- 2-5% of the adult male and post-menopausal female population
    • Most common cause of referral to gastroenterology
  • IMPORTANT: Iron deficiency anaemia is NOT a diagnosis but a sign (blood test- see below) often with symptoms (see below).
    • Whilst the cause may not always be found, it is important that a cause is investigated


  • History
    • PC- may be fatigue, SOB on exertion, palpitations
      • Other symptoms which may present include: sore tongue/taste disturbance; changes in hair/hair loss; pruritus; headache; tinnitus; angina (particularly if there is pre-existing CAD)
        • Rarely, other complaints may include dysphage due to an oesophageal web (Paterson Brown-Kelly/Plummer-Vinson syndrome)
        • In severe cases, patients can be SOB at rest; angina and ankle swelling
      • Ask about other symptoms e.g. of hypothyroidism or hyperthyroidism; weight loss; night sweats; etc which may be indicative of another cause AND ask about symptoms of diseases which may cause an iron deficient anaemia e.g. change in bowel habit, PR bleeding etc
      • Ask about any episodes of overt bleeding (particularly heavy periods in women- may be appropriate to take a full menstrual history, nosebleeds, PR bleeding etc)
    • Ask about PMHx and RHx
      • Drugs e.g. NSAIDs (peptic ulcer)
      • Previous GI disease/surgery
      • Recent illness
      • ?Recent blood donation
    • Ask about any FHx, Social Hx (in particular diet, but also smoking and alcohol (risk of cancer and other illness)), Travel history
  • Examination
    • On General examination
      • Pallor (can be particularly obvious in the mucous membranes e.g. conjunctiva, mouth etc)
      • Koilonychia (spoon shaped nails with longitudinal ridging)
      • Angular cheilitis
      • Beefy tongue (atrophic glossitis)
      • NB Be aware for signs of associated conditions which may be causing the anaemia e.g. stigmata of chronic liver disease; hereditary haemorrhagic telangiectasia, Peutz-Jeghers sydrome (pigmentation)
    • CVS examination may reveal a mild tachycardia (usually worse cases- rarely there may also be signs of heart failure (e.g. ankle oedema))
    • Abdominal Examination should look for any masses/organomegaly
      • +/- PR examination if appropriate (e.g. change in bowel habit, PR bleeding etc)
    • In patients with menorrhagia- see here for examination


  • Most commonly GI (in adult men and postmenopausal women)
  • Gynaecological (most common cause in premenopausal women)
    • Menstruation
    • Pregnancy (due to increased demand (x3) rather than loss)
  • Malabsorption
    • e.g. Coeliac, gastrectomy; PPI use
  • Other causes include
    • Blood donation
    • Poor intake (rare in non-pregnant individuals/growing children)
    • Rarely other sources of bleeding e.g. nosebleeds, haematuria etc could potentially cause anaemia


  • Blood tests:
    • For the diagnosis: FBC – Low Haemoglobin (anaemia) with microcytosis/Low MCV (microcytic).  Next check ferritin/iron levels (low <15μg/l)
      • NB Can be affected inflammation (e.g. rheumatoid, liver disease, malignancy, hyperthyroidism, kidney disease and alcoholism), can also be high even with anaemia
  • For identifying the cause
    • Screen for Coeliac disease (EMA/tissue transglutaminase antibody)
    • OGD (oesophagastroduodenoscopy) should be performed first if the screen is negative, then colonoscopy (if gastric cancer/peptic ulcer or other cause were identified on OGD)


  • Refer anyone with severe anaemia (Men <110g/l and Women <100g/l); patients with anaemia and signs of heart-failure; anaemia with dyspepsia; patients who do not respond to treatment or who have responded but subsequently developed anaemia again
    • (Women with menorrhagia and iron-deficiency anaemia, who don’t respond to first-line management of both, should be referred to gynaecology)
  • Iron supplementation should be given before the results of investigations
    • Ferrous fumarate is the first choice in Tayside (210mg TDS)
      • Ferrous sulphate is an alternative (and is often used first line in other areas)
  • Manage the underlying cause

Side effects and Follow-up

  • Most common side effect is gastric irritation e.g. heartburn, nausea, abdominal pain (for absorption- iron should be taken on an empty stomach but if side-effects are problematic, they may be taken after food)
    • Other side effects include constipation (stools also tend to go black); diarrhoea (less common)
  • Patients should have a FBC 2-4 weeks after starting treatment (to check if Hb is improving or worsening); in 2-4 months (to check improvement of Hb) and treatment should be continued for 3 months following this (Hb should be checked every 3 months for a year and then one year later)
    • If Hb does not improve,
      • Check compliance and manage side effects
      • If, after 2-4 weeks, Hb has not improved by more than 20g/l, refer to a specialist (Hb should rise by 10g/l every 7-10 days)
        • Transfusion is only really used in patients with CVS risk as a result of anaemia.
  • Patients with malabsorption or chronic gut disease may require parenteral iron replacement with iron sucrose (dose based on weight and iron deficiency)

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