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

Presentation

• 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

Causes

• Most commonly GI (in adult men and postmenopausal women)
  • Occult GI malignancy (e.g. gastric or colorectal cancers)
  • Peptic ulcer disease (check NSAID use)
• 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

Investigations

• 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)

Management

• 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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