Page 472 - Medicine and Surgery

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468 Chapter 12: Haematology and clinical immunology

These provide information on the degree of anaemia, about dietary iron intake, history of blood in faeces,
whether the disorder is confined to haemoglobin or menorrhagia and a history of taking nonsteroidal anti-
whether it includes abnormalities of white blood cells inflammatory drugs, aspirin or warfarin. On examina-
and/or platelets. The full blood count also provides in- tion there may be pallor, tachycardia, cardiac failure and
formation on the mean corpuscular volume (MCV) to specificfeaturesofirondeficiencyincludingglossitis,an-
guide further investigations. The blood film demon- gular stomatitis and brittle spoon shaped nails (koilony-
strates the morphology of red blood cells, white blood chia). A rectal examination should be performed.
cells and platelets.
In microcytic anaemia, a serum iron and ferritin, and

total iron binding capacity (TIBC) are measured to Investigations
Full blood count demonstrates a microcytic (low
assess iron stores.
MCV) hypochromic (low MCH, MCHC) anaemia.
In macrocytic anaemia with normal vitamin B 12 and

Blood film confirms small, pale staining (hypochro-
folate levels, or in suspected haematological malig-
mic) cells, variable shaped red blood cells (poikilo-
nancy, a bone marrow aspiration and trephine is usu-
cytosis) and variable sized red blood cells (anisocy-
ally performed (see page 466).
tosis). The white blood cells and platelets should be
normal.
Microcytic hypchromic anaemia Alow serum ferritin is the normal diagnostic investi-
gation; however, it is falsely raised in liver disease and
Iron deficiency anaemia renal failure.
Other tests include a low serum iron and raised total
Definition
iron binding capacity. Bone marrow aspiration is not
A fall in haemoglobin concentration secondary to de-
usually required, but shows erythroid hyperplasia and
pleted iron stores.
alack of iron stores on Perl’s staining.
Investigation of established iron deficiency may re-
Aetiology
quire faecal occult blood testing and upper or lower
Causes of iron deficiency:
gastrointestinal endoscopy.
Inadequate supply due to poor dietary intake (normal

requirements 0.5–1 mg per day).
Inadequate absorption, e.g. in coeliac disease or post-

Management
gastrectomy.
The underlying cause must be identified and treated
Increased demand such as during growth or preg-

where possible. Iron deficiency is treated with oral iron
nancy.
supplements, which should result in a rise of 1 g/dL
Increased loss from bleeding including occult gas-

of haemoglobin per week. Supplements are usually re-
trointestinal bleeding or menstruation.
quired for at least 6 months to replenish iron stores.
Failure of response may be due to poor compliance, se-
Pathophysiology
vere malabsorption, continued significant blood loss or
Most of the iron within the body is circulating as
another cause of anaemia. Rarely parenteral iron treat-
haemoglobin. The remainder is stored in the bone mar-
mentmayberequired.Inseverelysymptomaticanaemia,
row, hepatocytes and skeletal muscle cells. As an indi-
blood transfusion may be required; however, this may
vidual becomes iron deficient the bone marrow stores
interfere with subsequent investigations.
are depleted prior to the development of a microcytic
anaemia.
Sideroblastic anaemia
Clinical features
Symptoms of anaemia include fatigue, faintness, Definition
headaches and breathlessness. In patients with known Disordered haem synthesis resulting in abnormal accu-
iron deficiency anaemia, it is important to enquire mulation of iron within red blood cells.