iron deficiency anemia

Question 1

definition

Answer 1

Iron is essential for haem production. Prolonged deficiency leads to iron deficiency anaemia (IDA).

it is the most commonest cause of anaemia around the world (hence IDA and anaemia are often used synonymously)

there is defective synthesis of haemoglobin which results in microcytic and hypochromic red blood cells

Question 2

aetiology

Answer 2

Iron deficiency anaemia (IDA) is often multifactorial.

🌈 In pre menopausal women the most common cause of IDA is menstrual blood loss

🌈 in adult men and postmenopausal women, blood loss from the GI tract is the most common cause

Occult GI blood loss

• aspirin/NSAID use
• colonic carcinoma
• gastric carcinoma
• benign gastric ulceration
• angiodysplasia
• uncommon causes - oesophagitis, other gastrointestinal tract malignancies

Malabsorption

• coeliac disease
• gastrectomy
• helicobacter pylori colonisation
• uncommon causes - gut resection, bacterial overgrowth

Non-GI blood loss

• gynaecological - menstruation, pregnancy
• inadequate dietary intake - vegans, elderly,
• blood donation
• uncommon
• rarely - haematuria, epistaxis

In the tropics the high prevalence of iron deficiency is related to poor diet and to blood loss from hookworm infestation.

Question 3

SIGNS

Answer 3

• glossitis
• angular stomatitis - painful cracks at the angle of the mouth
• nail changes - spoon-nails (koilonychias); brittle longitudinal ridges occur in 10% of patients (1)
• dysphagia due to pharyngeal webs - Plummer-Vinson syndrome - usually seen in elderly or middle-aged women
• thin, fragile scalp hair
• modest splenomegaly - in a small number of patients (1,3)
• achlorhydria

Symptoms such as angina, marked ankle oedema, or dyspnoea at rest is not typically seen (in haemoglobin concentrations of more than 7 g/dL) unless there is additional cardiorespiratory pathology

Question 4

SYMPTOMS

Answer 4

Most patients complain of

• tiredness,
• breathlessness after exertion

Other less common symptoms include:

• headache
• tinnitus
• taste disturbances
• mental changes, such as pica
• sore tongue

Question 5

WHAT TO ASK IN CLINICAL HX

Answer 5

investigation and diagnosis

A full clinical history and physical examination should be undertaken.

inquire about

• use of aspirin and other NSAID’s
• family history of IDA - may indicate inherited disorders of iron absorption
• haematological disorders e.g. - thalassaemia
• telangiectasia and bleeding disorders
• family history of colorectal carcinoma

Question 6

IX FOR patients with no obvious cause for iron deficiency anaemia

Answer 6

• coeliac serology (presence of anti-endomysial antibody or tissue transglutaminase antibody) - The British Society of Gastroenterology suggests that all patients with IDA should be screened for coeliac disease
• upper and lower GI investigations - in all postmenopausal female and all male patients in whom iron deficiency has been confirmed (except when there is a history of significant overt non GI blood loss)
• urine testing for blood - since around 1% of patients with IDA will have renal tract malignancy
• stool examination - if appropriate to detect parasites
• testing for Helicobacter pylori - H. pylori colonisation may impair iron uptake and increase iron loss
• faecal occult blood tests is insensitive and non-specific and is of no value in the investigation of IDA

Question 7

WHAT WOULD FBC AND BLOOD FILM SHOW ?

Answer 7

• full blood count and blood film examination
  
  • recognise the indices of iron deficiency
    
    • reduced haemoglobin - Men <13.5 g/dl, women < 11.5 g/dl
    • reduced MCV - <76 fl (76–95 fl )
    • reduced MCH - 29.5 ± 2.5 pg (27.0–32.0 pg)
    • reduced MCHC - 32.5 ± 2.5 g/dl (32.0–36.0 g/dl) (1)
  • blood film
    
    • microcytic, hypochromic cells
    • occasional target cells and pencil-shaped poikilocytes
  • platelet count may be at or above the upper limit of normal if there is persistent bleeding
• haematinic assays:
  
  • decreased serum ferritin - best biochemical marker (in the absence of inflammation)
  • vitamin B12, folate
• serum iron and total iron binding capacity (TIBC)

The best proof of iron deficiency anaemia is that the anaemia is cured by administration of iron.

Question 8

WHAT IS TIBC

Answer 8

Total iron binding capacity is a measure of the total amount of iron with which plasma can combine. Most of the binding capacity is due to transferrin.

TIBC is increased in iron deficiency, pregnancy and by oral contraceptive therapy.

TIBC is decreased in:

• iron overload
• protein losing states } due to the fall in
• infections } plasma transferrin
• inflammation }
• neoplastic disease }

TIBC saturation tends to fall as serum ferritin increases and vice versa.

Question 9

RX

Answer 9

• established and correct any underlying cause to prevent further iron loss
• The main aim of iron therapy is to restore haemoglobin concentration and red cell indices to normal and to replenish iron stores
• Iron deficiency can usually be treated by oral iron supplements. Advising the patient on foods rich in iron may suffice although patients are often prescribed iron.
• Blood transfusion is usually considered for patients with symptomatic anaemia despite iron therapy or at risk of cardiovascular instability because of their degree of anaemia.
• The aim transfusion should be to restore haemoglobin to a safe level (not necessarily to normal levels) and then follow it up with iron treatment to replenish stores

Question 10

FOLLOW UP

Answer 10

Once the haemoglobin (Hb) level becomes normal, the Hb concentration and red cell indices should be monitored at intervals:

• recheck every 3 months for 1 year
• then again after a further year
• again if symptoms of anaemia develop after that In cases where the Hb or red cell indices fall below normal, additional oral iron should be given